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Have you ever seen a blast furnace? The picture below — molten iron pouring out from the blast furnace — might be familiar to you, and it could be the first thing on your mind when it comes to blast furnaces. However, seeing the blast furnace in real life isn’t a daily event.

The POSCO worker in the photo is clearing the area around the tap hole (an exit where the molten iron is discharged) so that the molten iron can smoothly flow out of the blast furnace. That is not easy since the discharged molten iron reaches over 1,500 ℃. However, POSCO employees can do this job owing to the pride and passion they possess for the blast furnace.

Iron ores become molten iron on entering the blast furnace. Then the molten iron is taken to the converter to filter all impurities. Next, the molten iron is shaped into large cuboids, which are then sent to different plants to be various steel products. This entire mechanism is called an integrated steelmaking process. The name says it all. It’s a process that flows continuously from the molten iron stage to the final steel product stage. So the entire blast furnace and steelworks are under operation 24/7 all through the year!

So, what if the blast furnace is idled? The blast furnace itself will be hardened into a huge mass of solid iron, so to restore the process and operate normally, it should be dismantled and replaced with a new one. The cost reaches 500 billion to 1 trillion KRW, and the reconstructing takes several months. Another problem is that it doesn’t end with just the blast furnace. As mentioned earlier, the steelworks is a continuous process, so if the blast furnace stops operation, all the plants that use the molten iron from the blast furnace need to cease their operation as well, meaning that the whole steelworks would have to be shut down.

That is why for the workers at POSCO, the blast furnace is like the subject of “sacred worship.” Did you know that torch lit with the sun was used to ignite the blast furnace No. 1 of Pohang Works in 1973? The records of POSCO history describes the moment very movingly, saying that “each torch relayers in turns took over the ‘flame of the sky.’”

▲ A sacred ceremony of the Olympic torch lighting in honor of Prometheus, who gave fire to humans. Inside the circle shows Tae-Joon Park lighting the torch with the sun to ignite POSCO’s first blast furnace (June 7, 1973).

As a result of this ceremony, the blast furnace has become a sublime object that must be protected for the POSCO workers. The commitment is as deep and heavy as the ancient Persian religion, Zoroastrianism, which cherished the fire used for rituals, and the people of the Stone Age desperate to preserve the flame which was obtained with much difficulty. The reason for this is because steel created with the ‘flame of the sky,’ laid the foundation for the development of the Korean manufacturing industry, and is everywhere in the advancement of the Korean economy.

There are some steelworks around the world where blast furnaces have been idled. As a result, other plants attached to it stopped operation as well, which led to the whole steelworks having to be shut down. As the steelworks were closed, the local economy collapsed as well, deteriorating the entire economy of a country eventually.

So idling the blast furnace is a big problem we need to pay attention because there is no simple solution when we look at the effects caused by it. If it’s shut down, the whole steelworks is closed subsequently. POSCO operates four blast furnaces at Pohang Works and five blast furnaces at Gwangyang Works, respectively. It is necessary to understand that if the furnaces stop operation, local economies might collapse as well. The consequence is enormous.

Although we’re not aware, our heart pumps and circulates blood throughout our body to keep us alive. POSCO blast furnaces are just like our ‘heart.’ They pour out molten iron 24/7 and help the economy of Korea ‘thrive.’

▲ A POSCO worker dealing with molten iron

POSCO’s furnaces are under operation based on cutting-edge technologies such as Big Data and AI. Due to this outstanding feature, POSCO was designated as a ‘Lighthouse Factory’ by the World Economic Forum (WEF) for the first time in Korea. When it comes to blast furnaces, the spirit of POSCO workers is still alive even in the high-tech world of today.

The answer to today’s question became a little serious, but we can’t help it. Because POSCO Newsroom — being a part of POSCO — also shares the pride and passion of the workers at the steelworks. POSCO Newsroom will be back with more interesting stories! See you next time!

* This article was written with help from Jun-Seok Park of POSCO Pohang Works Technology Development Section.

POSCO Pohang Works was selected as the ‘Lighthouse Factory’ for spearheading innovation in manufacturing by the World Economic Forum (WEF) in July last year, opening a new horizon for smart blast furnaces. The WEF consultant, who visited Pohang Works for site review, showed great interest in the live monitor-controlling of the blast furnace. This complex and huge furnace is controlled by pairing the expertise of POSCO workers with AI technology. On January 9, South Korea’s President Jae-in Moon visited the site and watched the world’s smartest furnace at work.

POSCO is also striving to strengthen its industrial ecosystem by sharing its Smart Factory platform with business partners — including SMEs. Let’s take a closer look at how POSCO is working on its Smart Factory and pursuing Corporate Citizenship.

l POSCO’s Blast Furnace — At the Forefront of the Fourth Industrial Revolution.

Since the term ‘Fourth Industrial Revolution’ was first used at the 2016 Davos Forum, it has become the mainstream of all industries. Companies started working on to quickly acquire the core technologies of the Fourth Industrial Revolution — like Big Data, Artificial Intelligence, and the Internet of Things. Twice a year, Davos has been designating factories that are leading innovation in manufacturing as ‘Lighthouse Factories’. Last July, POSCO became the first South Korean company to be announced as a lighthouse factory.

The No.2 blast furnace at Pohang Works could be called the core of the Fourth Industrial Revolution Technology. POSCO embarked on the ‘digitization’ of the blast furnace in 2016 when the term ‘Fourth Industrial Revolution’ came about. Since the blast furnace was originally dependent on field workers’ heuristic knowledge, by ‘digitization’, POSCO worked on standardizing all accumulated data.

The blast furnace is a gigantic facility with a height of 110 meters — equivalent to a 40-story building. Inside the blast furnace flows a mixture of solids and liquids whose temperature rises as high as 2300℃. All these factors make it impossible to ‘look’ inside the blast furnace, hence, digitizing the variables of this huge blast furnace was more complicated and difficult than expected. The seemingly impossible task of ‘standardizing data’ of human knowledge marked the start of the smart furnace.

The accumulated data became the base of big data. Since 2017, POSCO has been working on deep learning with big data. Through deep learning, the blast furnace can self learn from the numerous cases given. This process called, “Smartization” enables the system to predict and control the potential variables, and to derive optimal results. The IoT has also accelerated the establishment of smart furnaces. In the past, multiple factors such as molten iron temperature, the amount of fuel and raw materials, and so on were left to the manual labor of workers. However, through IoT, high-definition cameras and sensors can take care of the data automatically.

▲ The internal temperature of the furnace can go up to 2,300℃. In the inside, several materials like iron ore and coke are mixed, causing various chemical reactions. It’s like a huge pressure vessel that’s 40 stories high. POSCO succeeded in data standardizing and automating the blast furnace.

As a result, Pohang No.2 Blast Furnace has become capable of self-control and prediction to an artificial intelligence level, giving it the name, ‘AI blast furnace’. With the experience of experts who have worked for more than 30 years at ironmaking, the smart furnace boosted the daily production of molten iron by 240 tons. Annually this amounts to 85,000 tons with which automakers can produce 85,000 more cars.

There is always a concern that follows these kinds of changes, “Won’t AI make people lose jobs?” But the answer is “No.” Instead of looking into the furnace all day, workers can focus on more advanced work with their Domain Knowledge. This enhances the possibility of more creative performance.

l What Makes POSCO’s Smart Factory Special?

Currently, leading global companies are adopting the smart factory platform. Then what makes POSCO’s Smart Factory more special? The answer lies in the platform established for the ‘Continuous Processing’ — a special term of steelwork. POSCO doesn’t stop at applying this platform to just furnaces. It has gone on to extend these smart factories to the overall steelmaking process. PosFrame, the engine of POSCO’s Smart Factory, is its unique factory platform specified for continuous manufacturing processes.

The steelmaking process is continuous, running smoothly from production planning to delivering the final product to the customer. Therefore, applying the smart factory platform to steel works is quite challenging — with a much bigger scale — than applying to a single factory that produces a single item. Pohang Works is massive in size, with hundreds of factories manufacturing hundreds of different steel products. In such an environment, data from each site should be gathered, organized, and standardized so that anyone can process it. This is one of the main functions of PosFrame.

Let’s say that the steelmaking process starts from A and ends at Z. When PosFrame is applied completely to the steelworks, it is possible to trace the cause of an issue that occurred in Z to A.

▲ A Smart Factory operation concept in an integrated steelwork. The cause of an issue occurring at the later part of the process can be automatically tracked to the earlier part of the process, diagnosed, and resolved.

l POSCO’s Technology For All Business Partners to Share

How is Corporate Citizen POSCO dealing with this unique technology? POSCO isn’t planning on making this technology exclusive. Instead, POSCO is working on expanding the smart factory technology to business partners including SMEs.

Dongkuk Industries, which has factories in Pohang and Siheung, is a company that processes POSCO’s hot rolled steel into high-quality cold rolled steel. This product is then supplied to companies that produce automotive parts. At Dongkuk Industries, steel goes under the pickling process, where hydrochloric acid (HCl) is used to remove scale on the product surface. This takes a great deal of time since each customer demands different quality requirements. Since it is nearly impossible to match each requirement, Dongkuk Industries pickled all materials even though each POSCO hot rolled steel had different scales. Naturally, productivity decreased, and this is where POSCO’s Smart Factory technology stepped in.

First, through PosFrame, POSCO sends predicted data showing where and how much scale is on the supplied hot rolled steel. This predicted data is received at the “AI for optimal pickling” in Dongkuk Industries. In the past, the pickling conditions were calculated manually by workers, but now this AI automatically extracts the optimum value based on the data obtained from PosFrame. After pickling, the resulting data is passed back to PosFrame. As POSCO hot rolled steel is processed into high-quality cold rolled steel here, its data are accumulated in PosFrame as big data and advanced through repeated learning. The data on both sides are exchanged repetitively, enabling the production of an optimized product — as if produced in a connected plant. The application of the Smart Factory in Dongguk Industries minimized the time required for the pickling process while securing product quality required by the customer. This increased productivity by 60%, and high-quality material sales by 1.5 times.

▲ Dongkuk Industries established a Smart Factory with POSCO. (From the top left clockwise) the front view of the Pohang factory; the pickling line; the hydrogen furnace; and the wide shear line. (Photo credit: Dongkuk Industries)

POSCO is also concentrating on Smart Factory consulting for SMEs. This service isn’t limited to direct customers but expanded to other business partners, including secondary customers. POSCO has engaged in support service to build Smart Factory for shared growth with the Ministry of SMEs and Startups — establishing Smart Factory in 110 companies until last year. At the same time, POSCO also provides ‘Smartification Consulting’ to enhance competence, thus, delivering advanced field expertise through POSCO’s unique innovation technique QSS(Quick Six Sigma). By 2023, POSCO is to contribute 20 billion KRW to empower 1,000 companies.

POSCO is operating seven major programs for shared growth, and some of them are as follows — ‘Open Purchase’ offering fair trading opportunities; ‘Proper Payment On Time’ abolishing the lowest price bidding system and giving payment in cash on time; ‘Corporate Citizenship Job Matching’ training job seekers and arranging employment at partner companies. Additionally, POSCO has aided 1 trillion KRW, leading the way in establishing a Venture Fund of 2 trillion KRW, and a Venture Valley to support start-up activities for the youth.

POSCO has become the “lighthouse” of the global manufacturing industry with its Smart Factory. And in Korea, POSCO is actively working as a guide of Smart Factory for business partners.

Now the ‘FE Odyssey: “I Am a ButterFEly.”’, the final installation of the Blast Anatomy series, will follow the iron (FE) through its journey – all the way from its birthplace in mine to its final destinations, right around us. Better yet, the FE itself will walk us through the entire adventure!

Like a majestic butterfly who muddles through arduous stages – eggs, caterpillars then pupa – the journey of steel is just as rigorous: from iron ore buried deep in the mines until it finally presents its true self, as steel.

Join now to follow the FE Odyssey. POSCO Newsroom presents: “Blast Furnace Anatomy #3 – FE Odyssey: “I Am a ButterFEly.”

l Into the World – Like a Butterfly Fighting Its Way out of the Egg,
Iron Ore Makes Its Way out of the Mine

▲ Roy Hill Mine, Western Australia

I was born in Roy Hill mine in Western Australia, over 6,500 kilometers away from Pohang where one of POSCO steelworks is located. While buried deep in the ground of Roy Hill, I always dreamed of transforming into cool and chic steel products – a sturdy car, a slick home electronics, or a shiny stainless travel mug that offers people warm beverages.

Roy Hill mine has a total of 2.3 billion tons of iron ore deposits. POSCO started investing in Roy Hill mining project since 2010 now holding 12.5% of its shares. Roy Hill boasts the annual production of 55 million tons of iron ores. It’s huge! And that’s how so many of my siblings come from there. Besides Roy Hill, my other iron ore siblings also come from places like Canada and Brazil.

From the mine, do I travel straight to steelworks? Not exactly. I wish it were that simple. Before I get transported to the port in Australia, I make a stop at a laboratory for thorough testing – all my internal organs undergo rigorous testing. Using magnets, the lab technicians classify ores with high iron (FE) content. Fortunately, the iron ore that housed me passed the inspection, and I headed to the harbor so I can be sent to Korea.

My siblings and I boarded the transport ships to Korea. After 15 days of a long journey across the ocean, I can hardly forget the excitement I felt when we finally docked. Here we were, at the pier for POSCO’s raw materials, and I was stepping closer to my dream. Every year, 55 million tons of iron ores reach the POSCO docks – both Pohang and Gwangyang combined! These iron ores all share one dream and one dream only – the dream of becoming steel.

After we disembarked from the ship, we got stacked in raw materials yard. The raw material yards at POSCO steelworks measure to be 1.85 million m² – both Pohang and Gwangyang combined.* In that vast field of POSCO yard, I met some new friends – some were called ‘coal.’ Later on, when we reunited in front of the blast furnace, the coal friends would stand before me already transformed as ‘coke.’ Because coal could produce acidic dust, they would first travel to a place called ‘silo,’ an eco-friendly storage facility specifically designated for them.

*The Seoul World Cup Park: 2.1 million m².

When I looked closely, I noticed my iron ore siblings all had very different body types. We were all jagged and uneven. So we got separated, tossed and rolled around a lot, so our bodies can be shaped just right for the furnace. It was a lot of work, but I was so psyched – I knew I would soon get to travel into the blast furnace!

l Rites of Passage for Butterflies, So for the Iron Ores

As it turns out, I knew nothing of what it took to become steel. From the raw materials yard, I thought I would head straight into the blast furnace. Little did I know that I had to undergo one last stage – a process called ‘sintering.’ I also went through several other processes and entered a hot oven. As I got baked in it, I got more polished and solid. It was 1,300℃, so it was super hot, but I heard it’d be even hotter inside a blast furnace, so I got through it okay. After sintering, I transformed into sinter, a raw material for steelmaking, not an ugly and unpolished iron ore anymore!

As sinter, I passed through three filters, and right in front of the rotation chute, I reunited with the friends I’ve met earlier at POSCO yard. We would enter the blast furnace together. Through the rotation chute, we twirled and rolled around, a lot.

I heard some of my friends didn’t quite make it to the rotation chute. They didn’t pass through the filtering stages earlier. But I heard they were going to be reused as raw materials for the sintering instead.
I entered the furnace as sinter, but there were other raw materials like ‘sized lump’ and ‘pellet’. The sized lump came in just the perfect size right from the extraction. Relatively small iron ores became pellets through compressing and molding. Subsidiary materials like limestones also entered the furnace with me. Of course, the crucial fuel friends like coke, who help us melt, also joined us.

Facing the blast furnace, I got so nervous, so I took a deep breath to calm myself down. Because the temperature inside the furnace could reach as high as 2,300℃, it was rather hard to breathe, but my coke friend and I patiently took turns forming layers inside the furnace. As time went on, we traveled down. As we traveled down, we could feel the hot air flying up. Along with the hot air, I flew up in the middle of the furnace. I wasn’t quite sure where I would go next. Meanwhile, I heard my coke friend shouting, “hot air slapping!”

The coke hot aired by 1,200℃ air from the bottom, was oxidized producing carbon monoxide as a result. In turn, this carbon monoxide took oxygen away from me. These series of chemical reactions separated me from oxygen, and I became pure iron, FE! I finally transformed into molten iron and dropped to the floor. Along with my siblings, I roared in victory and exited the furnace through the tap hole.

l How Molten Iron Becomes Steel

I became molten iron, but the excitement was short-lived. To become steel, I have yet to face another set of journeys. As is, right out of the furnace, I was called ‘pig iron’ still containing several impurities like carbon, phosphorus, and sulfur. I still had to go through several processes inside the steelworks to reborn as a slick and beautiful steel product. The processes to come were: steelmaking, casting and rolling.

POSCO’s Pohang and Gwangyang Steelworks are integrated steelworks – because they have all the facilities to turn something like me, a piece of iron ore rock, into perfect and complete steel – all in one place. Let me walk you through each step.

Step 01. Steelmaking process – removing impurities from molten iron, molten iron becomes molten steel at this stage.
To become steel, I still had to shed impurities completely, and my carbon proportion had to be adjusted also. As pig iron, I exited the furnace through the tap hole and got loaded onto the ‘Torpedo Ladle Car’ and transported to the converter.

At this stage, the steelworks workers called me ‘molten iron,’ which meant pig iron made in the blast furnace. The torpedo ladle car is a specially designed car that transports molten iron. Each car, which can load up to 300 tons of molten iron, heads to the converter. Once I got to the converter, I saw scrap metals as well as pure oxygen. The carbon inside me became oxidized, and its proportion was reduced down to 0.3%. At this stage, I became independent from all the unnecessary impurities. Through this steelmaking process, I became molten steel – pure and optimized pre-steel. I wasn’t yet complete but was a ‘steel’ nonetheless, finally!

Step 02. Casting process – where the liquidated steel becomes solid.
As molten steel, I went into a mold, and through the continuous casting process, I got cooled and solidified to become intermediary materials like slab, bloom, and billet. It’s like shaping cookie dough with cookie cutters of various shapes and sizes. Slabs are used for plates or hot rolled coil; blooms for large steel bars or wire rods; and billets are made into small steel bars or wire rods.

Step 03. Rolling process – making steel into plates or wire rods.
After casting, slab, bloom, and billet pass through several rotating rolls taking a series of constant pressure. During this process, I either get thinned out or get stretched as per the client order – in whatever thickness or length. This is the stage where I can finally become wire rods, plates, or coils.

After the rolling process was complete, I underwent yet another rounds of check-ups to see if I had all the adequate qualifications as a steel product. At this stage, I even received an identification tag! I still remember myself waiting in the storage room excited to leave for the next destination. Some of my siblings got on a ship to the United States, and some of my big siblings got transported to the port in Ulsan in a specially designed truck.

l Like Butterflies Flying All Around the World, Steel Travels and Is Everywhere

To become an adult, butterflies must undergo long and arduous journey – first fighting its way out of the eggs, and going through caterpillar and chrysalis stages. Just like butterflies, I was merely a piece of rock at birth. Then, I became sinter, then a pure ‘FE,’ then finally, steel.

My dream came true. I became advanced high-strength steel (AHSS) and got used in a car, in hydrogen batteries – also in refrigerators and washing machines! Some of me became a bridge that crosses over an ocean. I was reborn as indispensable products in people’s lives.

And I don’t just mean me in contemporary society. Even my ancestors played crucial roles in sparking Industrial Revolution and in accelerating modernization. It’s a well-known fact the Industrial Revolution kicked off right around when the steam engine started being used as the main energy source. Simultaneously, the advanced smelting technique during the eighteenth century helped replace wood railways with iron railways. Together with the steam engine, trains became another momentum pushing the Industrial Revolution forward. Even after the Industrial Revolution, I was used everywhere as construction materials, in the machinery, for ships, cars, and home electronics. I was present all throughout human history.

I go on quietly carrying out my duties whether people notice me or not. I am hiding in guitar and piano strings creating beautiful melodies – and even in ticking clocks and car tires. Have you ever noticed my presence?

Like a caterpillar who turned into beautiful butterflies, I, who was once an unpolished piece of rock is now traveling all around the world in different shapes and sizes. Look around! You will notice I’m everywhere – and right next to you, at this moment.

l POSCO’s ‘Deep Learning’ Blast Furnace

POSCO embarked on the journey of smart technology back in 2016, the year when a super AI AlphaGo beat Se-Dol Lee, human champion of the game Go.

As disheartening as it was, Lee’s defeat became an awakening moment for Korea and an opportunity for POSCO to start digging deep on the relatively new concept, artificial intelligence. From that moment on, POSCO accelerated its research into AI and deep learning collaborating with top university researchers across the country to develop smart blast furnace.

The core of smart blast furnace technology is, ‘Deep Learning.’ Deep learning discovers patterns amongst countless random data utilizing it to predict the possible outcome just as human intelligence categorizes random items.

Let’s say there are thousands of random pictures – pictures of cats and dogs. A computer reads, analyzes, and categorizes the data from each picture, so the next time it ‘sees’ similar photos, it will recognize, determine and predict the correct pattern, thus identifying the picture as either cat or dog. Lots of companies are already utilizing this technology to analyze massive volumes of audio-visual data.

l What Is a ‘Smart’ Blast Furnace?

A blast furnace is a gigantic structure of 110 meters in height, taller than an average 40-story building – it makes molten iron. Inside the blast furnace flows a mixture of solids and liquids whose temperature rises as high as 2300℃. Since blast furnaces operate 24/7 non-stop, it’s difficult to ‘look’ inside a furnace.

However, the No.2 blast furnace of Pohang Steelworks is changing the game of steelmaking business. The ‘smart’ Pohang No. 2 furnace utilizes deep learning with an automotive system that monitors and auto-controls the inside conditions of the furnace.

POSCO started by defining the five variables that affect the conditions of a furnace. Then, countless random data was digitized for standardization. All the major data which used to be controlled heuristically is now measured live and become digital data paving a new path so the furnace can start learning deeply.

After the digitization completed, POSCO took on smartization process to establish a system to predict and automate the condition of the blast furnace. The key distinction between digitization and smartization is that smartization allows prediction. Because the data is so massive – over 1,000 types – the smartization process assigns algorithm appropriate for each data and perform analysis-prediction-control. Based on the rendered result, the system determines whether the inside conditions are good or bad – or can cause problems.

To put it simply, a smart blast 1) learns countless live-collected cases and data; 2) self-assesses the conditions of inputs (i.e. raw materials and fuels) and the furnace condition; 3) predicts the result of furnace operation; 4) automatically pre-controls the operating conditions; 5) yields the best combination result with minimum error.

l AI Furnace, Smarter than Humans

Every day, the visual data generated from the smart blast furnace daily reach up to hundreds of gigabytes. The smart furnace learns this massive amount of data and is getting smarter every day. What are the potential implications of this vast learning?

Before the smartization, the field employees used to personally measure the blast temperature every two hours, but now the bottom sensor of the furnace live-records the molten iron temperature. Not only does it live-record the current temperature, it also predicts the temperatures inside the furnace an hour ahead auto-adjusting the temperature of hot metal accordingly.

Furthermore, highly consistent algorithm assesses the inside condition of the furnace utilizing the thousands of images collected from the cameras installed on the tuyere nozzles. Based on the assessment, the smart furnace auto-controls the charging actions of iron ores and coke.

What about the skull? It’s layers of adhesives that stick to the furnace wall. To a furnace, it’s a cancer-like lump. What the smart system does is to analyze the images collected through furnace thermometers, sketch the overall shape of the skull, subsequently auto-controlling the charging mode.

Image source: ‘Shipment standby’ – By Tae-Ha Woo (20th Korean National Steel Day photo contest)

Currently, the Pohang No.2 blast furnace is the testing ground for this cutting-edge technology – the smart furnace boosted the daily production of molten iron by 240 tons. Annually this amounts to 85,000 tons with which automakers can produce 85,000 more cars. It is also a huge energy saver reducing the energy per ton of molten iron production.

One of the biggest achievements of the smart blast furnace is having stabilized the furnace management process through AI auto-control.

For the last three years, POSCO completed developing the auto-control system for each component of the blast furnace. Now the company is focusing on comprehensive integration. Going forward, POSCO plans to expand the applications to the Pohang No.3 and No.4 furnaces – they both have bigger internal capacity (5,600 ㎥) than the current No.2 furnace (2,550 ㎥).

POSCO took a giant step by adopting the world’s first thinking blast furnace. With time, more data will be collected, which will improve the quality and efficiency of molten iron production. In the era of the Fourth Revolution, POSCO will continue leading the way towards the smartization of steelworks across the globe.

Blast furnace produces molten iron, and it is indispensable to steelworks operation. With 110 meters in height, its scale is enormous.

All the steel products we see in our everyday lives are made from the molten iron. However, other than this simple fact, there really isn’t much we know about the blast furnace as what’s visible is its colossal steel exterior, not the inside.

What’s inside the blast furnace and how does it operate, with what technology? To help understand the details of blast operation, POSCO Newsroom presents ‘Blast Furnace Anatomy #1 – To the Heart of Steelworks Operation.’

l Earth, Fire, and the Wind: The Three Elements of Molten Iron

What gives birth to molten iron? It’s Earth, fire and the wind — these three elements come together in a blast furnace to create molten iron. How exactly? Let’s find out.

First, the iron ore, the raw materials for steel, comes from the Earth. Most iron ores — hematite, magnetite, limonite — contain an average of 60% of iron (Fe). Before the iron ores enter a blast furnace, it undergoes ‘sintering’ which turns the pristine iron ore into more compact and appropriate sizes.

The sintered iron ores become ‘sinter.’ The iron ores that come in just the perfect size right from the extraction are called ‘sized lump.’ The ores in microscopic scales are pelletized, which are called ‘pellets.’ Steelmaking utilizes all three materials as raw materials. Subsidiary raw materials like limestones are also used.

<Blast Furnace: Fuels & Raw Materials>

Now, the blast furnace will melt all the raw materials and extract only the iron (Fe), where coke and pulverized coal fuel the raw materials.

Coke is a grey, hard, and porous fuel made by heating coal up to 1000℃. Inside the furnace, coke is the main heat source melting various materials. It also acts as a reducing agent deoxidizing iron ores. The pulverized coal is a lump of the coal smashed into small pieces — of 0.125mm in size or less. Of the two, pulverized coal makes for a more economical option.

The raw materials and fuels alone do not magically create molten iron, of course. They will need the hot air inside the blast furnace — the hot air about 1200 ℃ in temperature. Then, the fuels and raw materials layered inside the furnace literally fly up inside the furnace! To better grasp the process, let’s slice the blast furnace in half and look inside.

This is what a blast furnace looks like. What exactly happens inside the blast furnace?

Fuels and raw materials enter the furnace through the top opening. The rotating chute evenly distributes the materials, landing them precisely at the due location. Then, the fuels and raw material layer in rotation — a layer of fuel, a layer of raw material, etc. Together, they create more than 40 layers of fuels and raw materials.

At the bottom of the blast furnace, the hot air of 1200℃ heats the materials and fuels. The hot air with a force of 4.0bar triggers such a force that the materials fly up in the air. Because of the heat, coke chemically dissolves the raw materials.

These processes produce molten iron, slag, and by-product gas at which stage, they are still mixed. Then, the by-product gas rises to the top while the molten iron and slag drop to the bottom. Once filtered through dust collectors, the gas transforms as a power source for steelworks. As for slag and molten iron, they are each separated for slag granulation and steelmaking. From the moment the raw materials enter the furnace, it takes about six and a half hours for the materials to transform into molten iron.

l And By-products? Recycle, Recycle, and Recycle

The by-product gases produced inside the blast furnace are released through the top pipe, mostly carbon monoxide, carbon dioxide, and nitrogen. For every ton of molten iron produced, the furnace emits about 1,600 cubic meters of gas. The gases go through primary and secondary dust collectors for purification. The purified gases are utilized to power different facilities at steelworks. This is how POSCO self-produces 74% of the electricity for its steelworks operation.

<Blast Furnace: The Journey of By-product Gases>

Other by-products from inside the furnace also include ingredients like silica (silicon dioxide) — not part of necessary ingredients to produce molten iron. To separate silica from iron ore, the subsidiary material limestone is added during sintering. Once inside the furnace, limestone combines with the silica and drops to the floor. The mixture is lighter than molten iron, so it layers above the molten iron. This mixture is another steelmaking by-product, slag.

Where does the slag end up? POSCO slag is recycled 100% as fertilizer and cement. Blast-furnace slag is rich in silicic acid, an excellent fertilizer for rice farming. Altogether 390,000 tons of POSCO slag was used for agricultural farming in 2018.

POSCO also developed POSMENT, an eco-friendly cement with a higher portion of slag which reduces CO2 emission up to 60%. Altogether 10.69 million tons of POSCO slag contributed to reducing 8.39 million tons of net greenhouse gas emissions.

l Is Blast Furnace Outdated?

Because blast furnaces have been around for so long, it could feel outdated. However, the furnace is full of sophisticated technology.

The sophistication starts from the very moment when the raw materials drop into the blast furnace. Landing them at the precise locations requires advanced technology. Precise calculation is crucial in all procedures — the order of insertion, in what sizes, how much, where, and at what timing. Based on these calculations, the rotation angle of the chute is adjusted, so that the raw materials and fuels distribute evenly inside the furnace.

Another part of the furnace technology involves the insertion of hot air into the furnace through over 40 holes. The timing must be steady. To boost productivity, pure oxygen is sometimes added to the hot air. There is also a facility that produces the hot air, which is called a hot stove. What powers the hot stove is the by-product gas produced in the blast furnace — recycled 100%. Such sustainable technology is at the core of POSCO’s competitiveness.

With the mixtures of solids, liquids, and gases creating many chemical reactions, it can be difficult to predict exactly what’s happening inside the furnace. With the 46 years experience of operating blast furnaces, POSCO has a reliable system to predict the condition of furnaces, however. At POSCO, the condition of blast furnaces can be monitored through live-data such as the temperature of the furnace, pressure, and the status of molten iron-making. Since the blast furnace operation is 24/7 nonstop, maintaining a stable condition has a critical bearing on the safe and economical operations of steelworks.

l Blast Furnace Shapes Korea’s Modern History

It’s no wonder the Pohang No.1 Blast Furnace was cited as Korea’s economic national treasure — for the immense contribution it sparked for Korea’s overall economic growth.

During the 1960s, when the whole country was still reeling from the wounds of the war, POSCO’s blast furnace provided an opportunity not only to lift the country off abject poverty but to continue — to hope.

Even at this moment, the Pohang No.1 Blast Furnace is making molten iron just the same — like the time when the golden molten iron poured out of the tap of the Pohang No. 1 blast furnace for the first time. The initial sentiment of the time might have faded, but the blast operation continues.

The U-Shaped Relationship

However, the argument is not so black and white according to Spyridon Stavropoulos, Ronald Wall and Yuanze Xu’s Environmental regulations and industrial competitiveness: evidence from China. The study suggests that the relationship between stringent economic regulations and industrial (or economic) competitiveness is U-shaped. Meaning, initially, stringent regulations will increase the cost of production and make companies less profitable, but after a certain turning point, companies will be forced to adapt and innovate, thus becoming more competitive in the long run.

Many activists sit on both sides of the debate. (Source: Ethical Shopper)

When regulation policies are consistent over a long period of time, companies are forced to tackle the root of the problem, instead of focusing on meeting certain numbers. In today’s global economy, many governments have already begun to implement stringent economic regulations that only look to get tighter in the future. In such a context, companies that choose to innovate and come up with solutions to global pollution problems will come out more competitive in the end.

Sustainability Equals Competitiveness

Looking at major economic players around the world, it’s safe to say that environmental sustainability is a common topic on each of their respective national agendas. Pressing national challenges are tied to the environment in one way or another. For example, many countries are shifting their policies to ensure energy security. Countries that import most of their energy from external regions are subject to volatile prices and thus unstable economies. Thus, governments are actively supporting companies that can cultivate domestic, renewable energy sources. Another, more obvious, example is the direct link between pollution and health risks.

China is the fastest developing country in the world, and by 2035, it will be responsible for 28 percent of the total global energy demand. China also happens to be almost completely dependent on energy imports. Subsequently, the government has started a variety of government programs to boost sustainability as part of President Xi Jinping’s pledge to build a “Beautiful China”. These policies also come in the wake of shocking statistics: in 2015, pollution led to 1.8 million premature deaths in China.

Chinese President Xi Jinping laid out a 2-step plan to achieve a “Beautiful China.” (Source: News Gru)

Sustainable Steelmaker

Even with strong government commitment and plenty of programs to support sustainable business, most developing countries lack affordable renewable energy sources and the technology to apply those sources to existing production processes. Nevertheless, the world is changing and only those that adapt and innovate survive and thrive. That’s exactly what POSCO did starting back in 2007.

FINEX: A Game Changer

POSCO came up with a new molten iron production technology called FINEX. The technology allows molten iron and non-coking coal to be produced directly in a blast furnace during the iron-making process. It is different from the conventional blast furnace process, as it combines the coking plant, sinter plant and blast furnace into a single iron-making unit. This lowers production costs and reduces harmful emissions.

FINEX is a sustainable game-changer for steel production.

Ultimately, FINEX is one of the most cost-effective and eco-friendly ways to make steel. The technology mitigates the use of C02, has the lowest process-related emission rates and preserves resources through the use of a wide range of iron ores and non-coking coals. FINEX reduces SOx and NOx emissions by 40 and 15 percent respectively, and fine dust particles can be reduced by 34 percent compared to traditional blast furnaces. Furthermore, the by-products from the process generate highly valuable export gas that can be used for various purposes like electric power generation or natural gas substitution.

On December 7, 2017, POSCO reached 20 million cumulative tons of molten iron production using the FINEX technology. POSCO is not the only company enjoying the benefits of sustainable competitiveness – POSCO’s manufacturing partners can see lower emissions levels when evaluating the entire life cycle of their products.

SEE ALSO: POSCO Reaches 20 Million Tons of Production Using FINEX Technology

Sustainability is no longer just jargon. As environmental issues are intricately tied to the economy and even national security, governments around the world will be actively supporting sustainable companies in the years to come. Companies can expect sustainability and competitiveness to become interchangeable terms in the near future.

On December 7, employees celebrated reaching 20 million tons and took a commemorative photo.

FINEX is an innovative, paradigm-shifting technology where molten iron is produced directly in a blast furnace. The process eliminates preliminary processing and uses cheaper powder-type iron ore and bituminous coal as raw materials. Subsequently, investment and production costs can be reduced by 85 percent compared to those of general blast furnaces of the same size. In addition, the technology reduces SOx and NOx emissions by 40 and 15 percent respectively, and fine dust particles can be reduced by 34 percent compared to general blast furnaces.

The beginnings of the technology date back to the 1990s when the Korean government chose POSCO’s smelting reduction steelmaking for a national project and contributed KRW 22.2 billion for research and development.

As a result, POSCO started operating the FINEX 2 plant with an annual production capacity of 1.5 million tons in 2007, and the FINEX 3 plant with an annual production capacity of 2 million tons in 2014, which now produces 10,000 tons of molten iron every day. Surprisingly, the Korean steel industry, which was heavily reliant on foreign technologies in 1968, now leads the world’s steel industry in terms of technology.

However, the path to success was filled with challenges.

In 1998, objections were raised against additional investment for the FINEX technology because there were no clear, tangible results even after KRW 60 billion was invested. Even so, POSCO management made a decision to construct a demo-plant with an additional investment of KRW 100 billion for technology development in order to secure long-term competitiveness rather than seeking immediate profit.   

In addition, POSCO convinced steelmaker Voestalpine, who was in possession of the world’s leading technology for molten iron production, to participate in the project as a partner. POSCO was able to do this by offering to cover the full cost of dispatched researchers and engineers should the technology become successful.

In 2003, there was a slight setback when the newly-opened core FINEX processing facility failed to operate successfully. However, after dozens of tests with 80 in-house professionals over 3 months, the facility was up and running.

Molten iron is produced directly in a furnace in the FINEX plant.

Sang-ho Lee, Director in Charge of Commercialization at POIST, said, “With less than 50 years of steelmaking experience, POSCO has managed to achieve a next-generation, innovative steel-producing technology. It feels great because even though POSCO started as a fast follower of foreign technologies, we are now a leading company in the world’s steel industry with our FINEX technology.”

POSCO currently has over 200 patents for its FINEX technology and HCI technology in Korea and 50 patents in more than 20 countries worldwide. Many overseas companies have expressed an interest in FINEX, and POSCO is in talks with world-renowned steelmakers in China to export its FINEX technology.

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What are Asphalt Roads Made of?

Asphalt roads are made of a mixture of aggregates, binders and fillers. The aggregates are typically iron and/or steel slag, sand, gravel or crushed rock, and they are bound together with asphalt itself, which is a bitumen.

Asphalt comes from natural deposits, or more commonly, as a by-product of the petroleum industry. It is a prevalent material for waterproofing, caulking and preserving, and is now most frequently used for road surfaces.

The iron and steel slag used as aggregates for asphalt roads are iron and steel by-products. Steel slag is residue from the steelmaking process, made of minerals like silica, alumina and titanium from iron sand, and combinations of calcium and magnesium oxides. During the steelmaking process, slags float on top of the molten iron, forming a barrier against oxygen and maintaining the internal temperature.

In road construction, these are the preferred aggregates as they harden well, enabling a thinner layer of pavement than what can be achieved with crushed stone aggregates. Slag is also very hardy, resistant to both weather and wear.

Steel slag is a sustainable aggregate for asphalt road production. (Source: National Slag Association)

According to the Washington State Department of Transportation’s Use of Steel Slag Aggregate in Pavements report in 2015, a high iron oxide content in steel slag aggregates creates pavement that is both hard and dense, making it a superior choice over natural aggregates such as rocks in creating hot mix asphalt.

Also, when used in bituminous pavements, slag offers the advantages of high skid-resistance, stability, resistance to rutting, fatigue resistance, deformation resistance, high cohesive strength and compatibility with typical asphalt binders. Steel slag is also used as a base course material, the material under the surface layer of an asphalt road, track or surface.

The Environmental Benefits of Steel and Steel Slag

Base course material containing iron and steel slag as well as asphalt mixture containing iron and steel slag were designated as a procurement item under the Green Procurement Law. These materials are recognized as items with environmental benefits. The use of slag minimizes environmental impact as it saves energy and conserves resources.

Steelmakers need to actively find ways to reuse steel by-products to reduce their overall waste. For example, POSCO is dedicated to reusing by-products of steel making as it has a strong commitment to environmentally friendly practices. In 2016, POSCO recycled 98.4 percent of its steelworks-generated by-products, 77 percent of which was blast furnace slag and steelmaking slag.

In fact, 88 percent of POSCO’s blast furnace slag is turned into granulated blast furnace slag for cement material. POSCO carefully tests all of its steel slag products before clearing them for reuse, ensuring that every market item is suitable for its intended application.

Hot slag, or steel waste, is poured into piles to cool before being used for asphalt road construction.(Source: Fractum)

While POSCO works to improve its recycling capabilities, manufacturing and other industries are starting to see the benefits of steel and iron slag. These materials are being used everywhere, from rail ballast to artificial ocean reefs.

Steel slag is far from industrial waste, as POSCO’s efforts show. This steelmaking by-product has serious potential, now and in the future, and is a highly versatile, easily-used material for road making and other applications.

Demand for sustainable materials is on the rise in flourishing industries such as construction and manufacturing. Steelmakers like POSCO who put by-products to full use and invest in research to apply them to different industries will share the economic benefits and play a vital role towards greener business practices in the coming future.

The Steelmaking Process

So, what does a blast furnace do in the steelmaking process? There are 4 main parts to the process of making steel, and in each process, the accompanying production equipment is as vital as the materials that make steel. Each batch of steel starts off with iron, molten iron to be exact, and the blast furnace is what transforms raw materials into molten iron.

Molten iron leaves through the bottom of a blast furnace

Molten iron comes from two raw materials; iron ore and coal. First, iron ore is converted into sinter ore in a sintering plant and coal is converted into raw coke using a coke oven. The processed materials are then poured into a blast furnace through the top opening. Hot air reaching 1200℃ is blown in from the bottom through tuyeres and chemically reacts with the materials as they fall to the bottom of the blast furnace. This process oxidizes the coke and reduces the sintered ore, creating molten iron. The molten iron is then further processed to make steel.

The Importance of the Blast Furnace

The Blast furnace is one of the oldest and most significant equipment in the steelmaking process. The average lifespan of a blast furnace is about 15 years before it needs to be replaced or refurbished.

The Pohang No.1 blast furnace

POSCO is a few months shy of its 50th anniversary, and the Pohang No.1 blast furnace has been in operation for 45 of those years. Interestingly, the blast furnace has never broken down or gone out of service. With an annual capacity of 1.3 million tons, it helped establish Korea as the top-5 steelmaker in the world and was even named Korea’s Economic National Treasure No.1.

A New Technology from an Old Furnace        

In the beginning of 2017, POSCO decided to shut down the Pohang No.1 blast furnace for good in response to the slowing steel market and put the national treasure in a museum instead. It seemed the oldest operating blast furnace in Korea would finally retire.

However, just before pulling the plug, engineers used the Pohang No.1 blast furnace in a pilot operation program using low-grade raw materials such as soft coke and low-cost iron ore to produce molten iron. To everyone’s astonishment, it succeeded, and with lower charter costs than the larger blast furnaces that have 3 times the production capacity.

As it turns out, because of its smaller size, the blast furnace can operate with low-grade raw materials such as soft coke and low-cost iron ore, and can flexibly adapt to fluctuations in operations. Employees further developed the technology and as a result, Pohang No.1 blast furnace recorded the lowest charter costs of all POSCO blast furnaces in April this year.

Thanks to the new-found technology, the legacy of the Pohang No.1 blast furnace will continue.

What’s the Secret to Longevity?

Usually, a blast furnace needs to be sprayed down every 6 months so that it does not get damaged from temperatures that can reach up to 2000℃. The bottom of the blast furnace is where the heat is concentrated, thus most susceptible to damage. Furthermore, fluctuations of the internal gas composition can lead to explosions. To solve this problem, POSCO’s technicians developed a technique to lower the coke to below the tuyere and repair the bottom of the blast furnace. This technology was applied to other furnaces and maintenance systems and is still in use today.

The Pohang No.1 blast furnace’s TFT during maintenance

To add, the Pohang No.1 blast furnace even has its own voluntary task force team (TFT) to care for and maintain the blast furnace called “Love for the blast furnace, love for POSCO.” The team of 15 not only makes sure the blast furnace is operating smoothly, they also continually research new technologies to prevent malfunctions and enhance the blast furnace.          

In a matter of months, the furnace went from almost becoming an artifact to a central part of POSCO’s competitiveness. This blast furnace’s long history in itself is impressive, but with its recent transformation, there is no telling what greater innovations and technology POSCO will achieve.

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China

A worker at Tarim Basin, the largest oil and gas-bearing basin in the People’s Republic of China. (source: Eco-Business)

China, as a developing industrial nation, emits one of the highest levels of carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides (NOx) and primary PM in the world. In 2013, it experienced the PM2.5 Crisis, and the government showed strong political will to battle air pollution with its Action Plan outlining ten goals to reduce air pollution by 2017. Fueled by anger from Chinese citizens over air quality, Beijing continues to heavily regulate air pollution as outlined in their 13th Five Year Plan (2016-2021), including the goal to have “good air quality day” readings for 80 percent of the year. It’s not all just talk in China, there is now no maximum monetary penalty payable for noncompliance, compared to the previous RMB 20,000.

The European Union

The European Environment Agency oversees the EU for environmental regulations (Source: Climateurope)

Air pollution regulations in the European Union (EU) are overseen by the European Environment Agency (EEA), which declared air pollution the number one environmental health risk in Europe. Most of the harm comes from vehicle and industry emissions. The EEA identified 5 key pollutants: nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOCs), sulphur dioxide (SO2) ammonia (NH3) and fine particulate matter (PM2.5). The EU set an emissions ceiling for its member nations to abide by from 2010 to 2019, and all but five countries are below that ceiling today. To add, as many as 5 member nations thus far have pledged to completely ban diesel and gasoline-fueled cars in the coming future.

Korea

Korean President Moon Jae-in talks to a crowd of people in Korea (Source: South China Morning Post)

With a new administration under President Moon Jae-in, Korea is committed to international environmental goals as a G20 member as well as making changes at home. Just last month in June, the government closed down a coal-fired plant that had been in operations for more than 30 years. Coal-fired plants are one of the major contributors of PM2.5, and the government has imposed new laws that ban the construction of new plants and encourage a general transition to natural gases. President Moon stated he will work to increase the natural gas market share in electricity production from 19 percent to 27 percent by 2030.

The government’s resolve to clean up the air affects coal-fired plants and plants using fossils fuels. The steel industry primarily uses such fuels and the need to find greener production processes is more urgent than ever before.

For POSCO, one of the biggest steel producers in Korea, efforts began back in 2007 when they jointly developed an iron-making process called Finex® with Primetals Technologies. The traditional way to produce iron is through a blast furnace which emits harmful substances into the air. The FINEX® Process combines coking plant, sinter plant and blast furnace into a single iron making unit, thus reducing production time, saving costs and resulting in drastically lower emission rates. With Finex®, sulfuric acid output was reduced by 60 percent, nitrate by 85 percent and scattering dust saw a 29 percent reduction. Even the byproduct of the iron-making process is an export gas that can be used for various purposes.

POSCO continues to strive to become an environmentally sustainable company with innovative material solutions, the application of AI (artificial intelligence) and IIoT (industrial internet of things) in their smart factory and their eco-friendly lithium extraction and rechargeable battery production. Such efforts have been recognized by the Corporate Knights which ranked POSCO 1st in metals and mining and 35th overall for their 13th annual Global 100 list of sustainable companies in 2017. Also, the Dow Jones Sustainability Index recognized POSCO for its sustainable management policies for 12 straight years.

The significant majority of leaders do agree on the need for collaboration to battle air pollution. Global citizens have growing concerns about environmental health risks such as PM2.5, and in response, many governments are enforcing tighter regulations and penalties on production companies. Companies now more than ever need to invest in new technologies and innovations for a greener world and bluer skies.

Cover image source: g20.org

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