scholarly journals Steel Slag Characterisation—Benefit of Coupling Chemical, Mineralogical and Magnetic Techniques

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 705 ◽  
Author(s):  
Maud Herbelin ◽  
Jérôme Bascou ◽  
Véronique Lavastre ◽  
Damien Guillaume ◽  
Mhammed Benbakkar ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Chemical Weathering ◽  
Steel Slag ◽  
Road Construction ◽  
Analytical Techniques ◽  
Mineralogical Composition ◽  
Spinel Solid Solution ◽  
Steel Making ◽  
Magnetic Techniques ◽  
Hazardous Metals

Steel-making slag is largely used today in road construction and other applications, but significant volumes are landfilled and cannot be recycled for excessive contents in hazardous metals, such as chromium or vanadium. The long-term behaviour of this material is still little known, and the characterisation of large volume slag dumps remains an environmental challenge. In this study various analytical techniques are used to characterise Electric Arc Furnace (EAF) slag landfilled for several decades and exposed to chemical weathering and erosion. Coupling chemical, mineralogical and magnetic techniques helps to understand the relations between hazardous metals and mineral phases. A special interest is given to Fe-bearing minerals microstructure so as to link the magnetic properties of the material to its mineralogical composition. The studied slag presents high amounts of chromium (between 1 and 3 wt. %) and very high magnetic susceptibility values (near 60 × 10−6 m3/kg), explained by the presence of magnetite and a spinel solid solution. Some correlations are found between magnetic susceptibility and potentially hazardous metals, providing new perspectives for future environmental investigations.

Steel slag quality control for road construction aggregates and its environmental impact: Case study of Vietnamese steel industry – Leaching of heavy metals from steel making slag

2021 ◽  
Author(s):  
Lan Huong Nguyen ◽  
Tien Dung Nguyen ◽  
Thi Viet Nga Tran ◽  
Duc Luong Nguyen ◽  
Hoai Son Tran ◽  
...  
Keyword(s):  
Quality Control ◽  
Steel Slag ◽  
Road Construction ◽  
Basic Oxygen Furnace ◽  
Test Methods ◽  
Leaching Test ◽  
Operation Condition ◽  
Steel Making ◽  
Slag Treatment ◽  
Current Utilization

Abstract Steel slag is an industrial by product of steel manufacturing processes and has been widely used in countries like Japan, United States, and European Union nations. However, the current utilization of steel slag in Vietnam is very low mainly because of lack of quality control of slag treatment and chances for reuse of treated steel slag. This paper presents the current steel slag production status and its potential to use as road construction aggregates in consideration of environmental and quality control issues. The basic oxygen furnace (BOF) and electric arc furnace (EAF) slag samples were collected from the seven large steel making factories of Vietnam and brought back to evaluate leaching amount from the slags. The batch leaching test methods were performed at laboratory using the leaching test of steel slag roadbed material in Japan (JIS K 0058 − 1) and Toxicity Characteristic Leaching Procedure (EPA method 1311) widely adopted in Vietnam. The results show that pH level and parameters such as T-Cr, Ni, Cu, Pb, As, Mn differ from the two test methods. The EPA 1311 seems too harsh to evaluate the environmental impacts because in the operation condition of the road, acidic liquid is absent. It is concluded that JIS test, which uses fresh water with gentle mixing not to degradation in size while leaching, is suitable for the evaluation, for the environmental assessment in service of the slag aggregate for roadbed.

scholarly journals THE EFFECT OF LONG-TERM STORAGE OF ELECTRIC STEEL SMELTING SLAGS IN DUMPS ON THEIR PROPERTIES

2020 ◽  
pp. 32-39
Author(s):  
Aleksey Pogromskiy ◽  
Tat'yana Anikanova
Keyword(s):  
Raw Materials ◽  
Steel Slag ◽  
Physical And Mechanical Properties ◽  
Road Construction ◽  
Mineral Resources ◽  
Mineralogical Composition ◽  
Electric Steel ◽  
Steel Smelting ◽  
Current Output ◽  
Main Component

construction, repair and reconstruction of roads require high costs of mineral raw materials in the form of sand, gravel, mineral powder. However, its reserves on the territory of our country are distributed unevenly, which causes significant transportation costs for the delivery of mineral resources to construction sites. In addition, mineral resources are inevitably reduced over time, which requires extensive involvement in the construction of roads of non-traditional types of raw materials, as well as industrial waste. The paper presents the results of studies of the properties of electric steel slag, the current output and stored in the dumps for several years. The main component of electric steel-smelting slags, both fresh and dumped, lying in dumps for about 20 years, is shannonite or γ-modification of calcium orthosilicate C2S. It has been established that the mineralogical composition of the Oskol Electrometallurgical Combine's slag is represented by hematite, wuistite, calcite, periclase, and also portlandite, formed during quenching of lime. Analysis of diffractograms of slags of different shelf life shows that in the initial periods of slag storage in the dumps there is a final quenching of lime and its carbonization with the formation of calcite. The results of the determination of the granulometric composition of the slag of different storage periods showed a decrease with time of the number of fine fractions and an increase in large fractions. It is established that when using electric steel-smelting slags in the construction and repair of highways, it is necessary to take into account changes in the physical and mechanical properties of materials. The processes that take place during the maintenance of slags in dumps determine the suitability of the use of slag mineral materials in road construction.

scholarly journals New EAF Slag Characterization Methodology for Strategic Metal Recovery

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1513
Author(s):  
Nour-Eddine Menad ◽  
Nassima Kana ◽  
Alain Seron ◽  
Ndue Kanari
Keyword(s):  
New Technologies ◽  
Slag Sample ◽  
Steel Slag ◽  
Analytical Techniques ◽  
Added Value ◽  
Metal Extraction ◽  
Magnetic Fraction ◽  
Magnetic Components ◽  
Physico Chemical ◽  
Hematite Fe2o3

The grown demand of current and future development of new technologies for high added value and strategic metals, such as molybdenum, vanadium, and chromium, and facing to the depletion of basic primary resources of these metals, the metal extraction and recovery from industrial by-products and wastes is a promising choice. Slag from the steelmaking sector contains a significant amount of metals; therefore, it must be considered to be an abundant secondary resource for several strategic materials, especially chromium. In this work, the generated slag from electric arc furnace (EAF) provided by the French steel industry was characterized by using multitude analytical techniques in order to determine the physico-chemical characteristics of the targeted slag. The revealed main crystallized phases are larnite (Ca2SiO4), magnetite (Fe3O4), srebrodolskite (Ca2Fe2O5), wüstite (FeO), maghemite (Fe2.6O3), hematite (Fe2O3), chromite [(Fe,Mg)Cr2O4], and quartz (SiO2). The collected slag sample contains about 34.1% iron (48.5% Fe2O3) and 3.5% chromium, whilst the vanadium contents is around 1500 ppm. The Mössbauer spectroscopy suggested that the non-magnetic fraction represents 42 wt% of the slag, while the remainder (58 wt%) is composed of magnetic components. The thermal treatment of steel slag up to 900 °C indicated that this solid is almost stable and few contained phases change their structures.

scholarly journals Strengthening the pavement bases through the use of stabilizing additives

2018 ◽  
Vol 5 (4) ◽  
Author(s):  
Dmitry Stroev ◽  
Sergey Sizonets ◽  
Vanik Kazaryan
Keyword(s):  
Road Construction ◽  
Mineralogical Composition ◽  
High Water ◽  
Base Layer ◽  
Cement Stone ◽  
Structure And Properties ◽  
Residual Deformations ◽  
Positive Properties ◽  
Mineral Binder ◽  
Structural Base

The experience of recent years of road operation shows that one of the ways to reduce the accumulation of residual deformations in the layers of road construction, expressed in rutting, the appearance of a grid of cracks and other types of transverse and longitudinal irregularities, is used in the base layers of pavements reinforced with mineral binders of crushed-stone-gravel-sandy mixtures (HGPS). The strength and deformability of hardened HGPS is determined mainly by the structure and properties of the cement stone, which holds the aggregate grains in place. The structure and properties of reinforced HGHPs depend on: the mineralogical composition, the water-cement ratio, the fineness of the cement, the age, the preparation and hardening conditions, or the addition of additives. With the introduction of additives, you can significantly change the strength and deformability of reinforced HGPS. Currently, stabilizing additives are widely used, the introduction of which allows to provide high water resistance, crack resistance and durability of the structural base layer. At the same time, a reinforced mixture with the use of additives has not only all the positive properties of HGPS on portland cement, but also eliminates its negative sides: low values of compressive strength, tensile strength in bending, and large shrinkage deformations. Based on the above, the introduction of stabilizing additives in fortified HGPS seems to be fruitful. As an additive, the stabilizer «ARMADOR» was used. The additive is a dry bulk mixture based on polymers, salts of alkali and alkaline earth metals. With the introduction of the stabilizer «ARMADOR», the physico-mechanical parameters increase in the composition of the reinforced material. This stabilizer creates strong crystallization and coagulation bonds, the use of which is recommended in conjunction with a mineral binder.

scholarly journals Enhancing the Flexural Strength of Concrete using Recycled Iron and Steel Slag Aggregate

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
A. A Raheem
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Concrete Beams ◽  
Steel Slag ◽  
Aggregate Size ◽  
Mineralogical Composition ◽  
Maximum Aggregate Size ◽  
Considerable Effort ◽  
Iron And Steel ◽  
Coefficient Of Uniformity

Concrete is strong in compression but weak in tension hence, considerable effort is required to improve concrete’s tensile strength by the use of pre-stressed concrete and addition of admixtures or additives. In this study, the use of recycled iron and steel slag (RISS) aggregate to improve the tensile strength of concrete was considered. The paper assessed the mineralogical composition of RISS and granite aggregates, and gradation. It also determines the effects of RISS aggregate on the flexural strength of concrete beams of 150 × 150 × 600 mm containing 0, 10, 20, 40 and 60% RISS aggregate replacement in mix ratios 1:1½:3, 1:2:4 and 1:3:6 with water cement ratios 0.65,0.60 and 0.55 respectively. Diffractograph of RISS and granite aggregate showed that RISS contains Magnetite, Ilmenite and Quartz, while granite contains Quartz, Annite, Microcline and Albite as the predominant minerals. The coefficient of uniformity and concavity of RISS and granite aggregate for maximum aggregate size of 37.5 mm are 4.35 and 1.33; and 4.64 and 1.76 respectively. Both aggregates contain quartz as the predominant mineral and are well graded. The result of the Flexural strength at 28 days curing is within 0.135 – 0.250 MPa specified byBS8500 – 2:2015. Flexural strength of concrete beams cast with RISS aggregate is relatively higher than concrete cast with granite aggregate. Flexural strength, a measure of tensile strength of concrete is improved as percentage RISS aggregate increased.

scholarly journals Experimental Study on Precipitation Behavior of Spinels in Stainless Steel-Making Slag under Heating Treatment

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 487 ◽  
Author(s):  
Jianli Li ◽  
Qiqiang Mou ◽  
Qiang Zeng ◽  
Yue Yu
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Steel Slag ◽  
Calcium Content ◽  
Heating Time ◽  
X Ray Diffraction ◽  
Stainless Steel Slag ◽  
Steel Making ◽  
Heating Treatment ◽  
The Stability

The stability of chromium in stainless steel slag has a positive correlation with spinel particle size and a negative correlation with the calcium content of the spinel. The effect of heating time on the precipitation of spinel crystals in the CaO-SiO2-MgO-Al2O3-Cr2O3-FeO system was investigated in the laboratory. Scanning electron microscopy with energy-dispersive and X-ray diffraction were adopted to observe the microstructure, test the chemical composition, and determine the mineral phases of synthetic slags, and FactSage7.1 was applied to calculate the crystallization process of the molten slag. The results showed that the particle size of the spinel crystals increased from 9.42 to 10.73 μm, the calcium content in the spinel crystals decreased from 1.38 at% to 0.78 at%, and the content of chromium in the spinel crystal increased from 16.55 at% to 22.78 at% with an increase in the heating time from 0 min to 120 min at 1450 °C. Furthermore, the species of spinel minerals remained constant. Therefore, an extension in the heating time is beneficial for improving the stability of chromium in stainless steel slag.

Skidding Characteristics of Pavement Surfaces Incorporating Steel Slag Aggregates

1996 ◽  
Vol 1545 (1) ◽  
pp. 35-40 ◽  
Author(s):  
A. F. Stock ◽  
Colin M. Ibberson ◽  
I. F. Taylor
Keyword(s):  
Steel Industry ◽  
Steel Slag ◽  
Road Construction ◽  
Specimen Preparation ◽  
Skid Resistance ◽  
Performance Measurements ◽  
Performance Expectations ◽  
The Past ◽  
Set Up

Steel slag, a by-product of the steel industry, has been used in road construction in South Yorkshire and its environs for the past 60 years. Local highway engineers have anecdotal evidence of good long-term antiskid performance from road surfacings that incorporate steel slag aggregate, and these materials have remained popular with users. In view of the move toward performance measurements for paving materials, a systematic study of the performance of paving materials incorporating slag has been set up as a combined industry-university project with the assistance of the Teaching Company Directorate. The evaluation of the skid resistance characteristics of steel slag aggregates and the skidding characteristics of pavement surfaces incorporating steel slag aggregate are reported. The research program developed a modified specimen preparation procedure that significantly reduced the scatter in polished stone value (PSV) results. The field data showed that all steel slag surfaces provided good long-term skid resistance and that the 14-mm chippings exceed the performance expectations of rock chippings with similar PSVs.

Novel Sustainable Composites with Geopolymeric Steel Slag and Recycled from Packing PET

2020 ◽  
Vol 1012 ◽  
pp. 26-31
Author(s):  
Eliziane Medeiros Santos ◽  
Alaelson Vieira Gomes ◽  
Flávio James Humberto Tommasini Vieira Ramos ◽  
Sergio Neves Monteiro
Keyword(s):  
Polymer Composites ◽  
Environmental Impacts ◽  
Moisture Absorption ◽  
Steel Slag ◽  
Future Studies ◽  
Steel Making ◽  
The World ◽  
The Matrix ◽  
Sustainable Product ◽  
Sustainable Materials

The search for sustainable materials has been increasingly growing due to the world environmental impacts faced. With the improper disposal of PET packaging and the waste generated by steel making, such as slag, a composite of these materials was created in search of a sustainable product. The composite has as its matrix the polymer and its particles are geopolymeric of the steel slag. The polymer composites were manufactured with concentrations of 0%, 20%, 40% and 60% of geopolymer. The characterizations showed that they are composites with low moisture absorption and that the affinity between the matrix and the reinforcement is impaired as the amount of charge increases. It was possible to realize that composites are good materials for future studies for possible future applications, such as ballistic vests. Composites are great precursors for achieving product sustainability due to the feasibility of reusing waste and disposing of it improperly in the environment.

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