On May 28, POSCO launched a sea forest cultivation program in Ulleung Island to mark the National Ocean Day (May 31).

Earlier in the month, POSCO installed 100 Tritons* and 750 Triton blocks underwater and fostered a sea forest reaching 0.4ha in Ulleung Island. The installed Tritons have been acknowledged as artificial reefs by the Ministry of Oceans and Fisheries. The 100 Tritons were placed on the edge of the sea forest to facilitate the growth of marine algae while 750 Triton blocks were stacked up in the center, serving as a habitat and breeding ground for fish.

* Triton: The name Triton is taken after the god of the sea in Greek mythology. It is an artificial reef brand made with POSCO’s steel slag. The materials used to make Triton has proven to be safe for the environment as well as for marine life.

About 20 attendants were present at the event, including Ulleung Island Governor Byung-Soo Kim, fishermen of Ulleung Island, President of POSCO In-Hwa Chang, and RIST President Seong Yu. They inspected the sea forest site where the artificial reefs were installed.

In 2000, POSCO, together with RIST, developed an artificial reef Triton made with steel slag, a co-product of the steelmaking process. The company provided steel slags that amount to a total of 6559 Tritons free of charge. The Tritons were placed in 30 different sea forests in South Korea. In this case of Ulleung Island, POSCO not only provided the steel slag but also participated directly from the production to the installation stage.

Steel slag, the main material of Triton, has high mineral content such as calcium and iron, which are useful for marine ecosystems than general aggregates. Not only can the Triton facilitate the growth of marine algae, but it can also promote photosynthesis, thus restoring the marine ecosystem and diversifying coastal organisms as well. Also, the Triton reef can withstand typhoons and tsunamis due to its high gravity and strength and is highly resistant to seawater corrosion.

POSCO is focusing on the Triton sea forest cultivation project as one of the major Corporate Citizenship activities. The project is expected to restore the marine ecosystem and has a Blue Carbon effect since it absorbs and stores CO₂ underwater. RIST and other related organizations have revealed that sea forests are capable of storing 3 to 16 tons of carbon dioxide annually per hectare.

Ulleung Island Governor Byung-Soo Kim said, “We are glad that POSCO has stepped in to help resolve the issues of the marine ecosystem here in Ulleung Island.“ President of POSCO In-Hwa Chang explained that POSCO, as a Corporate Citizen, will actively take part in contributing to the local community with POSCO’s technology.

POSCO explored different underwater sites around Ulleung Island since December last year and selected the best location to cultivate a sea forest. In April, the company conducted a thorough investigation to understand the existing biological habitat. And finally, this month, POSCO transported the Triton to Ulleung Island and installed them underwater. POSCO and Ulleung Island will continue follow-up management — including research of water quality, supplemental planting of marine algae, and exterminating harmful organisms.

POSCO plans to develop sustainable sea fertilizer and a new type of artificial reef using steel slag. These developments are expected to contribute to restoring the marine ecosystem and also help improve the income of local fishermen.

■ The cultivation process of the Triton sea forest

STEEL Talk presents to you interesting stories of Science, Technology, Energy, Environment, Life — and of course STEEL!

POSCO volunteered spreading silicate fertilizer at a farm in Gwangyang last year. Since POSCO is a steel maker, the connection with fertilizer might seem odd. However, steel and fertilizer are quite close — closer than we think. Let’s see how these two go together.

l What Is Silicate And What Is Slag?

To make iron, iron ore is first smelted in a large blast furnace. After this, the iron ore is separated into molten iron and stony by-product. This by-product is called a ‘blast furnace slag.’ A blast furnace slag has a specific gravity different from molten iron, so it is easily separable.

When slag is first separated, it looks like hot molten lava. So to cool it down, high-pressure water is sprayed on it. After it cools down, the slag takes a sand-like form, and this is called ‘granulated slag.’ The granulated slag is then dehydrated and pulverized into pellet-like shapes about the size of 2 to 5mm. This slag is rich in silicic acid (SiO₂), which is essential for rice farming, so it is made and utilized as a ‘silicate slag fertilizer.’

The main component of silicate fertilizer is silicon (Si). Silicon is not an essential component for plant growth itself, but it is a vital component for the rice plant since 5-10% of its weight is silicic acid — the rice plant is even nicknamed a ‘Silicate Plant.’ Silicon is the most abundant in soil, but because it doesn’t separate well, the rice plant can not absorb the silicic acid. That’s why you need silicate fertilizer. Silicate fertilizers provide the rice plant with silicic acid that is absorbable — enhancing its ability to withstand heavy rainfall, strong winds, and pests.

In Korea, rice that is sticky with a weak scent is generally considered ‘good’ rice. Silicate fertilizer lowers the protein content in the rice, improving the taste and enhancing the quality and standard of the rice.

Slag, which is a by-product of ironmaking at steelworks, contains 25-30% of soluble silicic acid. POSCO has contributed to increase farm income by continuously supplying slag to fertilizer companies since 1974, the year after the Pohang Works began operation. Did you know that all silicate fertilizer used in Korea is made from POSCO slag? In the past 45 years, a total of 13.76 million tons of silicate fertilizers have been supplied to domestic rice paddies.

l Make The Earth Greener

It is a known fact that greenhouse gas causes global warming. In terms of carbon dioxide emissions from the agricultural and dairy industries in Korea, the numbers add up to 21 million tons per year — with 29% accounting from rice paddies. The use of silicate fertilizer is set to help reduce the amount of greenhouse gas emitted.

Since rice is grown with water-filled into the paddies, the organic matters in the paddy soil break down into methane (CH₄). Research from agricultural experts states that the iron ions (Fe3 +) in the slag fertilizer reduce the methane concentration from the paddy fields by 15-20%. The fertilizer is also expected to contribute to the ultimate reduction in greenhouse gas emissions by 1.1 to 1.5 million tons per year in Korea!

Increasing the use of silicate slag fertilizer is helpful to all — farmers, fertilizer companies, and the whole environment. First of all, the fertilizer improves the soil quality, which in turn enhances rice quality and grades. This eventually leads to higher incomes for the farming communities. For the government, the use of fertilizer reduces methane gas from the paddies, decreasing the amount of overall greenhouse gas. Also, better rice taste boosts the consumption of rice, which increases the competitiveness of fertilizer companies. So silicate slag fertilizer is not only environmentally conscious but also beneficial to the whole society.

POSCO plans to expand the demand for silicate slag fertilizer and develop overseas export markets so that the by-products are recycled well all around! (๑❛ᴗ❛๑)

[See more about the use of by-products here!] POSCO’s Eco Driver: Steel 2

* This article was written with help from Keon-Mok Sohn of POSCO By-Product Recycling Group

– Finding the Hidden POSCO! –

Discover POSCO’s Heartbeat!

① Saving the Waters with ‘POSCO Volunteers for Clean Oceans’

Launched in 2009, POSCO Volunteers for Clean Ocean started with a group of passionate scuba divers who are POSCO employees. Since then, they have been volunteering to collect various ocean wastes and starfish from Pohang, and Gwangyang where POSCO steelworks are located. POSCO Volunteers’ cleaning activities also extended to other areas like Incheon, Gangneung and Ulleungdo.
They’ve collected 1,650 tons of marine debris through over 540 underwater clean-up activities. Their volunteering is not just saving the oceans but also helping improve the livelihood of local fishermen.

With #SteelSaveEarth campaign this year, POSCO is channeling its effort on collecting plastic wastes from the ocean. The work of POSCO Volunteers for Clean Oceans will continue to protect Korea’s water resources and marine ecosystem.

② Never-Ending Community Service ‘With POSCO’

The employees of Pohang Steelworks continue practicing the spirit of community service through donating their talents. POSCO’s talent volunteer group participates in regular weekend volunteer activities to spread the company’s ‘With POSCO’ principle that seeks mutual growth. Recently, mural painting volunteers created color murals near the Pohang canals where many tourists visit. Various other POSCO volunteers also participated in senior care, especially those living alone, replacing old wallpaper, floorboards, and lighting to help improve their living conditions. POSCO employees are regularly donating their time and talents as a way to express their gratitude toward the community. Altogether 10 volunteer groups are active in the region, participating in such activities as mural painting, reforms, electric repairs, senior care, technical volunteering, tutoring, and ocean clean-ups.

③ ‘STEEL HOUSE’, the POSCO Exclusive

POSCO STEEL HOUSE is designed to protect people and their properties from disasters like earthquake, typhoons, and fires, by applying stronger and more durable techniques than any other construction methods. STEEL HOUSE is a residential structure using internal and external steel with a thickness of 1mm. Strong enough to withstand earthquakes and yet, it has a short construction period. With thin walls, STEEL HOUSE can create a spacious living space, making it an economical choice for both constructors and residents. Because it uses a dry construction method, not only can it be built quickly, it can also be constructed at any time of the year.

Since 2009, POSCO has been collaborating with the National Fire Agency of Korea to support fire-stricken communities. POSCO employees, firefighters, and POSCO’s youth volunteer group Beyonders regularly roll up their sleeves to build steel houses and provide safe living spaces for the fire victims across the country.

④ POSCO Creates Sea Forests and Restores Marine Ecosystems

A coral reef is an underwater ecosystem. Reefs are formed of colonies of polyps held together by calcium carbonate providing a home for many precious marine species. What if POSCO could create this coral reef? It sounds slightly unbecoming perhaps, but there are actually good reasons backing this unusual idea. Triton, an artificial reef developed by POSCO, is made of slag, a steelmaking by-product. Slag has high mineral content such as calcium and iron, which are useful for marine ecosystems than general aggregates. Not only can the Triton help grow algae, but it can also promote photosynthesis purifying contaminated sediments and water. Also, Triton reef can withstand typhoons and tsunamis due to its high gravity and strength. It also reduces CO₂ through carbonation and algae photosynthesis. The World Conservation Congress and the World Business Council for Sustainable Development recognized the positive contribution POSCO’s Triton is making towards the marine ecosystem and announced it as one of the best practices. In 2018, POSCO used 1,418 tritons and 12,200 underwater rocks to help expand clean spaces for the marine ecosystem.

⑤ POSCO Steel Gives Rise to Rice!

Produced during the ironmaking process in the blast furnace, slag contains various impurities other than iron. POSCO’s slag is 100% recycled as either fertilizer or cement. Quality furnace slag is rich in silicic acid, an important ingredient to ensure a large rice harvest. Last year, about 390,000 tons of POSCO slag was used as agricultural fertilizer. Slag fertilizer not only increases the crop yield, but it also improves the taste of rice. Slag is not just a recyclable steel byproduct — as an excellent fertilizer, it is also a tremendous source of joy for farming communities.

⑥ Eco-friendly High Performance POSMENT

In addition to fertilizers, furnace slag also transforms into cement! POSCO developed the eco-friendly POSMENT back in 2012 after 10 years of persistent R&D effort to recycle slag. Instead of limestone, POSMENT mixes slag into general cement for added strength. Compared to conventional cement, POSMENT can reduce up to 60% of greenhouse gas emissions. In 2018, 10.69 million tons of POSCO slag were used as cement helping reduce 8.39 million tons of net greenhouse gases.

⑦ Pohang’s Cultural Hub, POSCO’s Hyoja Art Hall

Since its opening in 1980, Hyoja Art Hall has been providing free performances and concerts for POSCO employees and Pohang residents. The performance facilities and safety management have seen a steady improvement, but POSCO invested in a full remodeling of the space last year to further improve the audience’s experiences. In 2006, Hyoja Art Hall was selected as an excellent performance facility and has been at the forefront of implementing “With POSCO” vision through free performances for the residents, and free rentals to help develop local talents.

If Hyoja Art Hall is the cultural hub of Pohang, what about Gwangyang? Opened in 1992, Gwangyang’s Baegun Art Hall holds 990 seats and is a cultural hub of Gwangyang, Like Hyoja, Baegun has been presenting various cultural events including classical music concerts, musicals, plays and films for POSCO employees and the local population, free of charge.

⑧ Pohang International Fireworks Festival — With POSCO!

On the first night of June this year, Pohang’s night sky was laced with vibrant colors. Established in 2004, the Pohang International Fireworks Festival celebrates its 16th event this year. In the conception stage of the Festival, POSCO focused on two themes: ‘light’ which the city of Pohang signifies and ‘fire,’ strong imagery of the blast furnace at Pohang Steelworks. Since then, the event grew to become global-scale and the themes of the Festival are much more diverse than simple flame imageries. Regarded as one of the top summer festivals in Korea, Pohang International Fireworks is now attended by over 2,000 visitors and features not only spectacular fireworks but also various street performances, culture exchange programs as well as movie screenings.

Though it might seem invisible, POSCO is indeed breathing all around us. And we’re not just talking about its products and technologies. As a corporate citizen, POSCO’s constantly reaching out to spread its community spirits. Perhaps, the most essential is invisible to the eyes but can be felt only with the heart. Beyond hardware, POSCO’s creating many pieces of ‘heartware’ across every corner of our communities. Listen. POSCO’s heart is beating strong — here and now.

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.