FAQ - Frequently Asked Questions

It is a product generated necessarily from the production of a certain leading product - in case of ArcelorMittal Tubarão, it is the STEEL. It is also possible to define it as a material derived from industrial processes, which has some technical application and becomes economically viable by means of recycling. This definition makes the big difference between co-products and residue (material resulting from activities or services of an organization, which is usually solid or semi-solid and that, because of its characteristics, it does not have any technical application or economic viability). Among the co-products resulting from the production of steel, we have the Steel Slags, Blast Furnace Granulated Slags, dusts from dedusting systems, sludge from wastewater treatment plants, tar, among others.

2) What is the quantity of co-products generated at ArcelorMittal Tubarão?

The generation of co-products is directly related to the production of steel (ArcelorMittal Tubarão main product). Currently, ArcelorMittal Tubarão has been producing around 500 Kg of co-products and residues per ton of steel. Out of these, the Slags (Steelmaking and Blast Furnace) represent 70% of this generation and the residues such as dust, sludge and scale, account for 30% of this generation.

3) What are the types of slag?

ArcelorMittal Tubarão produces two types of slag: Blast Furnace Slag and LD Steel Slag.

Blast Furnace Slag is produced in units called Blast Furnaces; it results from the production process of Hot Metal. The so-called Blast Furnace Slag undergoes a forced cooling process performed by high-pressure water jets (quenching), keeping the excess water and not enough time for the formation of crystals. This slag granulates, then becoming "vitrified" and is called Granulated Blast Furnace Slag.

The LD Steel Slag is produced in units called LD Oxygen Converters at ArcelorMittal Tubarão's steelmaking plant. It results from the transformation of Hot Metal into Steel. The Steel Slag is then transported to the steelmaking plant until the slag yard where it is tilted and cooled by water jets. However, this cooling process is not forced, thus allowing for the formation of crystals. From the cooling it undergoes different processes, then generating various types of slags commercialized by ArcelorMittal Tubarão: LD NP Slag, In Natura Slag (Steel Slag) and ACERITA®.

4) Does the expansion of LD Steel Slag pose any prohibiting factor for its application?

The Steel Slag has always been considered a problem due to its volumetric expansion caused by the contents of free CaO and MgO, which when in contact with water, suffer hydration reactions. Nevertheless, this expansion does not impede its application, as long as special cares are taken during the process. This expansion can also be controlled, such as the case of ACERITA®, which undergoes an expansion reduction treatment. It is permanently monitored through laboratory assays and tests foreseen by the DNIT standards, and upon reaching an expansion value that meets the technical standards, the process is interrupted and the material is made available to the market. For further information, please contact our sales department.

5) Does the application of LD Steel Slag for the agriculture business pose any environmental risk for both the soil and the ground water?

The researches undertaken by the Federal University of Viçosa regarding the assessment of LD Slag for agricultural use, are comprised of several tests on possible environmental risks for both the soil and ground water. A leaching test was undertaken in a laboratory, utilizing soils of regions from the states of Minas Gerais and Espírito Santo, plus the LD Slag, which assessed the mobility of the existing chemical elements. Another test was carried out in a greenhouse, utilizing regional commercial cultures such as sugar cane, soybean and coffee, in the waters that were percolated and collected through lisimeter. According to the studies undertaken, the presence of heavy metals was not detected in the samples, consequently, there is neither risk of soil or ground water contamination, nor the possibility of metals absorption by the plants.

Design Foster Copyright 2007 - ArcelorMittal Tubarão Privacy Policy

Siderúrgica produtora de placas de aço, aços planos, bobinas e laminados a quente.