Application Of Steel Slag Research Articles

Production, characterisation, utilisation, and beneficial soil application of steel slag: A review

Slags are a co-product produced by the steel manufacturing industry and have mainly been utilised for aggregates in concreting and road construction. The increased utilisation of slag can increase economic growth and sustainability for future generations by creating a closed-loop system, circular economy within the metallurgical industries. Slags can be used as a soil amendment, and slag characteristics may reduce leachate potential of heavy metals, reduce greenhouse gas emissions, as well as contain essential nutrients required for agricultural use and environmental remediation. This review aims to examine various slag generation processes in steel plants, their physicochemical characteristics in relation to beneficial utilisation as a soil amendment, and environmental implications and risk assessment of their utilisation in agricultural soils. In relation to enhancing recycling of these resources, current and emerging techniques to separate iron and phosphorus slag compositions are also outlined in this review. Although there are no known immediate direct threats posed by slag on human health, the associated risks include potential heavy metal contamination, leachate contamination, and bioaccumulation of heavy metals in plants, thereby reaching the food chain. Further research in this area is required to assess the long-term effects of slag in agricultural soils on animal and human health.

A Review of Modified Steel Slag Application in Catalytic Pyrolysis, Organic Degradation, Electrocatalysis, Photocatalysis, Transesterification and Carbon Capture and Storage

As a by-product of the iron and steel industry, steel slag is rich in catalytically active substances and can therefore be used as a solid catalyst. Many studies have shown that the application potential of steel slag in catalysis is huge, which provides new development space for its application, thereby increasing its additional utilization value. This article primarily reviews the research progress in catalytic fields such as catalytic pyrolysis, organic degradation, electrocatalysis, photocatalysis, transesterification, and carbon capture and storage, as well as the modification methods of steel slag. The catalytic performance of the modified steel slag has been further improved, and it has the meaningful characteristics of high efficiency, cleanliness, and low costs.

The application of steel slag in a multistage pond constructed wetland to purify low-phosphorus polluted river water

To investigate the effect of a constructed wetland (CW) with steel slag as the filler on water contaminated by low phosphorus levels, a multistage pond CW system was designed in this study. Low-phosphorus polluted river water was used as the research object. This study explored the effects of using steel slag as a CW filler on phosphorus removal and the total phosphorus (TP) purification effect of the wetland system. The results showed that the TP removal rates in the ecological pond, oxidation pond, surface flow wetlands and submerged plant pond were 5.17%, 8.02%, 21.56%, and 16.31%, respectively. Intermittent increases in phosphorus concentration were observed in the reactors and were caused by the decay of plant tissues, which released pollutants. Because steel slag was added to the filler, the TP concentrations in the effluent of the first- and second-level horizontal subsurface CWs increased by 151.13% and 16.29%, respectively, compared to the influent concentration. The 20th to 40th days of the test run was a period of rapid phosphorus release of the system. The use of steel slag has a potential risk of phosphorus release when applied in CWs used to purify low-phosphorus contaminated water bodies.

Compaction Procedures and Associated Environmental Impacts Analysis for Application of Steel Slag in Road Base Layer

In recent years, recycling steel slag is receiving growing interest in the road base layer construction field due to its role in alleviating land occupation and resource shortages. However, the mixture compaction and its environmental impact on practical construction sites remain unclear, which may hinder the application of steel slags in road layers. This study investigates the pavement construction of the ‘Baotou-Maoming’ motorway, located in Inner Mongolia, China, analyzing the compaction procedures and assessing the environmental impacts caused by the road base layer containing steel slag. Firstly, mechanical properties and texture appearances of the steel slag aggregates are characterized. Afterwards, the comparative assessments for steel slag and andesite layers compaction are quantified from equivalent CO2 emission and energy consumption aspects, respectively. The results show that the steel slag has a better surface texture than the natural aggregates; physical properties including compactness, flatness and compressive strength comply with the requirements for applying steel slag to a hydraulically bound mixture. Compared to the base layer using andesite aggregates, the compaction vibration period of the course containing steel slags should be reduced to achieve a proper density due to the “hard-to-hard” effect that occurs between the adjacent steel slag particles. Consequently, the additional energy and the equivalent CO2 are generated at 2.67 MJ/m3 and 0.20 kg/m3, respectively.

Flue gas desulfurization (FGD) steel slag ameliorates salinity, sodicity, and adverse physical properties of saline-sodic soil of middle Yellow River, China.

Saline-sodic soil is considered the most important low-yield soil in arid and semi-arid regions. Flue gas desulfurization (FGD) steel slag is a kind of by-product from wet FGD process, in which steel slag powder replaces lime as sorbent of SO2 emitted from coal-fired power plants. It could potentially be used to ameliorate saline-sodic soil. In this study, a large-scale field experiment of applying FGD steel slag as a new amendment of saline-sodic soils was conducted in the middle YellowRiver, Inner Mongolia, China. The FGD steel slag was applied at a rate of 180 t/ha in 2015, 2016, and 2018, respectively. After FGD steel slag application for 1, 3, and 4 years, the soil samples were collected. The saline-sodic field without FGD steel slag amendment was used as the control treatment (CK). Compared with control, the application of FGD steel slag significantly (p < 0.05) decreased soil pH, electric conductivity (EC), salt content, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of surface soil in saline-sodic soil. However, FGD steel slag increased the EC and salt content at the lower depth of soil profile because of the salt accumulation leached from surface soil. The FGD steel slag significantly increased the concentration of Ca2+ and reduced the concentrations of Na+, Cl-, CO32-, and HCO3- ions. FGD steel slag was beneficial for improving adverse physical properties of saline-sodic soil. The application of FGD steel slag significantly reduced the plastic index, tensile strength, and the formation of cracking in saline-sodic soil. The FGD steel slag reduced surface area density of crack (Dc) and average crack width (AW) by 49.1% and 58.7%, compared with the control. The reduction of soil cracking was contributed to the release of Ca2+ from FGD steel slag to exchange the Na+ on the soil cation exchange sites, which decrease the clay dispersion in soil. The findings of this study confirmed that FGD steel slag could effectively and rapidly remediate saline-sodic soils through decreasing soil sodicity and improving poor physical properties.

A Review of the Application of Steel Slag in CO2 Fixation

AbstractSteel slag is the main by‐product during the steel manufacturing process, with the characteristics of large output and low utilization rate. Since the high content of calcium oxide in steel slag, it is often used for CO2 capture. In this paper, progress on the development of steel slag for fixing CO2 is reviewed. This review is organized according to the carbonation type of steel slag, including direct carbonation and indirect carbonation. For direct carbonation, it is introduced from two parts: aqueous carbonation and gas‐solid carbonation. For indirect carbonation, it is summarized according to the extracting agent. The carbonation condition and capacity will be carefully discussed. Besides, the techno‐economic assessments of using steel slag for CO2 capture are discussed. This paper will provide an overview of the steel slag using for CO2 sequestration available and valuable suggestions for future study.

Characterization of steel slag and its effect on rice production in Latosol and acid sulfate soil

Most soils in Indonesia need soil ameliorant material. There are various ameliorant materials that can improve soil properties. The researchers propose steel slag as an alternative ameliorant material. Steel slag is a waste from steel manufacturing, and the amount is very abundant. Unfortunately, steel slag falls into the category of hazardous and toxic waste (by regulation). It is still questionable and needs verification that this material is potential for agriculture. In this study, an analysis of the characteristics (total chemical and micronutrient content) of steel slag was carried out. Besides, the steel slag was applied to Latosol and Acid Sulfate Soil (ASS) planted with rice plant to see its effects on it. The results show that steel slag is rich in Ca, Mg, P, Si, micronutrients, and low in heavy metals. The steel slag application for rice plants on Latosol and ASS show a positive effect. Rice production on soil with steel slag addition is higher than control. The optimum doses of steel slag are 6 tons/ha for Latosol and 9 tons/ha for ASS. It indicates that steel slag is a potential ameliorant material and needs reconsideration to exclude it from its category as hazardous and toxic waste.

Application investigation of high-phosphorus steel slag in cementitious material and ordinary concrete

It is essential to utilize high-phosphorus steel slag (SS) effectively. The retarding effect of phosphate on the setting time is investigated, the retarding mechanism of high-phosphorus SS is concluded. The hydration activation of high-phosphorus SS in cementitious material are studied with additives of calcium oxide and sodium sulfate. The application of high-phosphorus SS with composite admixture of blast furnace slags (BFS) or BFS + fly ash (FA) is investigated. The main properties such as setting time, flexural strength (FS), unconfined compressive strength (UCS), hydration mineral, microstructure, etc., are investigated. The results show that the soluble phosphate would be generated during the depolymerization and dissolution processes of vitreous bodies in high-phosphorus SS, the retardation effect of soluble phosphate is greater than that of insoluble phosphate. The approximate amounts of calcium oxide and sodium sulfate for the hydration activation are 4% and 1%. To ensure sufficient later UCS of concrete, the high-phosphorus SS content is suggested not to be over 35%. To ensure optimal mechanical performance, the range of blended mixture is recommended as 30–40%. The blended proportion of high-phosphorus SS, slag and fly ash is recommended as 1:2:1. This investigation is new at present and important to the recycling of high-phosphorus SS.

Reducing Production of CO2 and CH4 from Peaty Paddy Soils through Applying Slag in South Sumatera, Indonesia

The change of anthropogenic peatlands to agricultural lands could have negative impacts, namely soil subsidence due to oxidation processes, and reduce the stock of soil organic carbon due to the increase of greenhouse gases (CO2 and CH4) emissions which contribute to global warming. Stability of converted peatlands could be increased through amelioration of soil by applying steel slag. A laboratory experiment was conducted with using factorial complete randomized design with ten combination treatments, including slag application, of peat soil samples collected from paddy fields in South Sumatera. This study determined the effect of steel slag application on reducing greenhouse gas (CO2 and CH4) production from cultivated peatland soils. The first factor of experimental treatment was peaty soil from 5 different locations, and the second factor was the application of steel slag. The highest production potentials of CH4 and CO2 were shown by peaty paddy soils from Kayu Agung and Plaju, respectively, while the lowest fluxes were shown by Indralaya’s peaty paddy soil. Peaty paddy soil from the Indrajaya site produced the lowest CO2 and CH4 compared with other sites. Application of steel slag ameliorant reduced CH4 and CO2 emissions by 19.24% and 18.95%, respectively, on average. Slag ameliorant also reduced acidity of peaty paddy soils.

Thermal Exchange and Skid Resistance of Chip Seal with Various Aggregate Types and Morphologies

Steel slag, the by-product of steelmaking, is a desirable alternative material for natural aggregate. However, there are few studies applying steel slag in the preventive maintenance of asphalt pavements, especially chip seal. The main objective of this study is to explore the feasibility of applying steel slag in chip seal and the effect of steel slag on the thermal exchange and aggregate retention properties. Furthermore, the surface features, including texture depth and skid resistance. of chip seal were also evaluated. The results show that the thermal exchange performances of chip seal vary with aggregate types. The ranking of the chip seal samples according to the cooling rate places ferrochromium (FER) slag as the fastest and basic oxygen furnace (BOF) slag as the slowest, with the basalt (BS) falling in between. The use of FER slag can make the chip seal resume traffic about ten minutes earlier than original samples. The skid resistance and texture depth of FER slag meet the requirements of the specification, although they are less than those of ordinary aggregates. Moreover, FER slag has a better aggregate retention performance than BOF slag and BS due to its spherical particles and alkaline surface. The application of steel slag in chip seal can recycle industrial waste, reduce the consumption of natural resources and promote economic pavement maintenance technology.

Soil correction for planting bermudagrass using steel slag or limestone

Abstract Limestone is the most commonly used acidity-correction agent in tropical soils. However, steel slag can be an alternative for turfgrass production areas because it contains silicon, which can increase turfgrass tolerance to biotic and/or abiotic stresses. This study was developed to evaluate the effect of the application of steel slag, as compared with limestone, on a bermudagrass sod production system. The experiment was carried out in Botucatu-SP, Brazil, in a randomized block design arranged in a factorial scheme 2 × 5 with 4 replications. Treatments consisted of two correctives (steel slag and limestone) and their rates, which were calculated to raise the soil base saturation to 12% (current), 30%, 50%, 70% and 90%. The application of lime and steel slag rates had positive effects on soil chemical attributes related to acidity correction, such as pH, Ca, Mg, H + Al, Al, CEC, SB, and base saturation (%). The slag provided higher levels of P, Ca, and Si, whereas limestone increased the Mg soil content. Steel slag provided a higher ground cover rate for bermudagrass than limestone at 114 and 161 days after transplanting (DAT), with maximum cover rate achieved with 60% base saturation at 161 DAT. The turfgrasses treated with slag showed a higher amount of roots, rhizomes, and stolons when compared with those treated with limestone. It is suggested the use of steel slag and, in calculating the need for corrective, 90% soil base saturation.

Investigation of Heavy Metal Cd, Pb and Cr in Andisols as Affected by the Amelioration of Steel Slag and Rice Husk Bokashi

The application of steel slag and bokashi of husk in Andisols has been acknowledge to decrease P-retention and increase available P. However, steel slag contains heavy metals that may harm soils. The objective of this research was to find out the effect of amelioration steel slag and bokashi of husk in Andisols on the heavy metals contents (Cd, Pb and Cr) in the soil. The treatments were arranged in randomized block designed in factorial pattern with two factors: steel slag and bokashi of husk, each consisted of four level: 0, 2.5, 5.0 and 7.5 % in 10 kg soil weight (w/w), thus the total was 16 combined treatments and repeated three times. The treatments were incubated for four months and then the P-retention, available P, Cd, Pb and Cr contents in the soil were analyzed. The results showed that steel slag and bokashi of husk interacted in decreasing 6.67% of P-retention and increasing 60 ppm of available P. This research also informed that Cd, Pb and Cr contents in the soil after the treatments were still lower than the critical value that were permitted.

Application of steel slag in cement treated aggregate base course

Steel slag, which can be used as a cementitious material, is widely used in road engineering. However, it is less applied in the base course. The feasibility of the application of steel slag in the road base was examined and the optimal replacement content of aggregate was determined. Different contents of steel slag (30%, 50%, and 70% by volume) were blended into the concrete. The mechanical and durability performance of the mixture were tested. The microstructure and elements distribution were characterized by the scanning electron microscopy (SEM) and the energy dispersive X-ray spectroscopy (EDS). The experiments manifest that steel slag is beneficial for the reinforcement of the strength and shrinkage performance of concrete, making it possible to replace aggregate. The unconfined compressive strength (UCS) change trend at 7d is positively related to cement content. The blend with 50% of steel slag has the maximum strength and stiffness at 4% cement content. In pace with the steel slag amount increases, the freeze resistance and dry shrinkage performance of samples increase, but the temperature shrinkage performance decreases. Besides, the minimum mass losses of samples are those with 50% of steel slag. The microstructure results imply the addition of steel slag increases the amount of hydration products, making the structure tighter and of lower porosity. Molecular simulations also reveal steel slag increases the electrostatic interaction and bonding effect with cement. The addition of steel slag into the road base is feasible, with the best overall performance obtained at the content of 50%. Steel slag mixture has sound economic benefit and potential great environmental benefit compared to limestone mixture. It is worth reminding when steel slag is applied in an engineering project, production process control of steel slag aggregate is required.

Simulation and property prediction of MgO-FeO-MnO solid solution in steel slag

RO phase in steel slag is form by divalent oxides of magnesium, iron, and manganese. The activity and expansibility of MgO-FeO-MnO solid solution were affected by the content of FeO and MnO, which further affects the application of steel slag in building materials. The micromorphology of MgO-FeO-MnO phase was diverse in different steel slag, and was affected by Fe, Mn content and grain boundary wetting phase transitions. By synthesizing MgO-FeO-MnO solid solution to simulate RO phase, it was found that the hydration activity of the solid solution will increase with the decrease of FeO/MnO, but only up to 23.275% of MgO in MgO-FeO-MnO solid solution can be hydrated. Unhydrated MgO affects the volume stability of steel slag. It is also a hidden danger in the application of steel slag in building materials.

Experimental Research on Steel slag Stabilized Soil and its Application in Subgrade Engineering

An experimental program was carried out to explore the feasibility of steel slag replacing lime used in the pavement of highway subgrade. The compaction test, the bearing ratio test, the unconfined compressive strength test, the splitting tensile strength test and the water stability test were carried out for different mixture ratio. And field test was also carried out to verify the application of steel slag. The test results showed that the immersion bearing ratio of steel slag stabilized soil increased with the increase of compaction degree and content of steel slag. The CBR value of Steel slag stabilized soil with 8–15% slag content was basically equivalent to that of 4% lime soil. The failure strain of 8% or 15% steel slag soil is larger than that of lime soil or cement soil. The strength of lime soil, cement soil and steel slag stabilized increased monotonously with the increase of curing age, but the growth rate of lime soil was significantly higher than that of steel slag stabilized soil. The 7d unconfined compressive strength of 8% steel slag stabilized soil reached 0.41 MPa, which met the requirements of highway subgrade materials. The initial moisture content had a great influence on the steel slag stabilized soil, and it was necessary to strictly control the moisture content for subgrade constructing. The content of steel slag in the steel slag stabilized soil was measured by EDTA method which is effective. The deflection value of 8% steel slag stabilized soil was 130.8 (10−2 mm), which can meet the requirements of the design specification [232.9(10−2 mm)].

An overview of resource utilization of steel slag as absorbent material for waste water treatment

With the rapid development of the steel industry, the accumulation of steel slag increases year by year, occupying a large amount of farm land and leading the problem of environmental pollution and safety hazards. The current comprehensive utilization rate of steel slag is still very low in China, far behind the developed countries. The low comprehensive utilization rate of steel slag is a stumbling block to the green and sustainable development of the Yangtze River Economic Belt. Improving the comprehensive utilization rate of steel slag is an imperative way to resolve these problems and to realize sustainable development for the steel enterprise. Steel slag presents porous structure and large surface area; in addition, it is easy to separate from water due to its high density. Therefore, the application of steel slag in industrial waste water treatment has received intensive attention in recent years. This paper systematically introduced the research progress of steel slag resource utilization as absorbent materials for waste water and proposed the important improved method and critical problems for steel slag as absorbent materials.

Research progress of steel slag asphalt concrete

Steel slag asphalt concrete is one of the important components of asphalt concrete. There are some differences between the steel slag asphalt concrete and ordinary asphalt concrete. Based on the research of scholars at home and abroad, this paper systematically introduces the steel slag characteristics and excellent performance of steel slag asphalt concrete, summarizes the problems existing in the practical application of steel slag asphalt concrete, and provides references for its promotion and application.

Enhancement mechanism of skid resistance in preventive maintenance of asphalt pavement by steel slag based on micro-surfacing

Steel slag is nowadays widely used as aggregates for asphalt pavement construction. It can minimize the environment pollution resulted from reducing natural aggregate consumption and recycling solid waste. However, there are few studies on application of steel slag in the preventive maintenance and its enhancement mechanism on surface skid resistance is still unknown. Laser scanning technic and digital analysis method were combined in this study to explore this issue. The morphology of basalt and steel slag was firstly quantified by imaging analysis and then used as fundamental backup for further explanation. Profile features of micro-surfacing samples containing steel slag were captured and studied. Meanwhile, wet track abrasion test and loaded wheel test were conducted to verify mechanical feasibility of using steel slag in the micro-surfacing. Results show that replacing basalt with steel slag could increase the positive texture significantly, due to the morphological differences between steel slag and natural aggregates. Positive texture contribution and peak profile contribution of steel slag can guide to design micro-surfacing with good skid resistance. Abrasion losses, lateral and vertical displacement are all decreased after replacing basalt with steel slag due to a stronger interlocking structure, indicating that steel slag can increase the ability of micro-surfacing to resist traffic loading.

Effects of lime and steel slag application on soil fertility and soybean yield under a no till-system

Steel slags can be used in agriculture, as they are composed of CaO, MgO, SiO2, and compounds such as P2O5, FeO, and MnO. The solubility of slag may be higher than that of lime, which can make this residue an excellent source for soil acidity correction in no-till systems. However, there are few studies reporting their benefits when applied to the soil surface. This study evaluated slag amendment effects on soil chemical attributes and on the yield and nutrient uptake of soybean following surface application and/or incorporation of different types of slag, in comparison to lime, on a tropical, acidic soil under a no-till system. The trial was performed in Botucatu, SP, Brazil. Six soil-acidity corrective materials were incorporated or surface-applied, including steel slag, ladle slag, stainless-steel slag, wollastonite, dolomitic lime, and calcined dolomitic lime, plus a negative control. Each material dose was calculated to raise the base saturation to 70%. Slags can be applied in a no-tillage system with efficiency similar to that of lime for the neutralization of soil acidity, for adequate nutrition and yield of the soybean crop. Slags and limes showed similar effects on increased pH, decreased Al3+concentration, and increased base saturation up to the 0.40 and 0.20-m soil layers at 12 and 23 months, respectively, after the application of treatments, regardless of surface or incorporated application. The by-product application has an additional advantage, depending on the type of slag, that is the provision of phosphorus and/or silicon.

Study on Preparation and Performance of Steel Slag Asphalt Mixture Based on Steel Slag Aggregate

The comprehensive utilization of steel slag has always been a worldwide problem. Under the background of vigorous development of highways in China, the application technology of steel slag in asphalt concrete will make the steel slag resources hopefully get a large number of reasonable utilization. Based on the application of steel slag in asphalt concrete, the basic physical and chemical properties of different types of steel slag were investigated. The blast furnace slag was used as the aggregate to prepare the asphalt mixture. The mixture was tested by research and test. The uniaxial compression test and the indirect tensile test were used to evaluate the low temperature crack resistance and fatigue resistance. The test results show that the surface texture of steel slag is rough and the embedding effect is good, which is beneficial to enhance the adhesion with asphalt and improve the shear resistance. The steel slag asphalt mixture has good low temperature deformation ability and small expansion ratio, which can be paved to meet the driving conditions. Required asphalt concrete pavement.