Utilization Of Steel Slag Research Articles

Comparison of Properties of Steel Slag and Natural Aggregate for Road Construction

It is becoming a more challenging task to find suitable alternatives to natural aggregate for making concrete, as nearly three quarters of the volume of concrete contained of natural aggregates only. Steel slag is an industrial by-product of steel industry and India is India is the 3rd largest steel producer in the world with total steel production of 95.6 MT per annum. It possesses the problem of disposal and is of environmental concern. The industrial waste has been encouraged in construction industries as a substitute for natural resources for many years such as fly ash. Concrete is used more than any other material in the world so the demand for aggregate in construction industry is increasing rapidly. In this paper the physical, chemical and mechanical properties of steel slag are found out and compared with the properties of natural aggregate. It is found that the properties of steel slag are nearly same as that of natural aggregate which enhances the possibilities of utilization of steel slag as substitute for natural aggregate.

Process to utilize crushed steel slag in cement industry directly: Multi-phased clinker sintering technology

To improve the utilization efficiency of steel slag in cement industry, cement clinkers are prepared by simulated multi-phased clinker sintering technology with crushed steel slag (without grinding). The results show that after high temperature treatment, the inert components and tough phases of steel slag such as iron phase, calcium ferrite phase and RO phase (CaOFeOMnOMgO solid solution) are reduced; the soundness, grindability and hydration activity of steel slag can be certainly improved; hydration activity of the multi-phased cement at early age is a little lower than that of grade 42.5 ordinary Portland cement, while develops faster than later. The multi-phased cement clinker prepared at 1400 °C with the raw material contains 16.86% steel slag has comparable grindability and soundness to the normal Portland cement clinker. Compared to traditionally using steel slag as a cement raw meal, the multi-phased clinker sintering technology has much greater technical and economic advantage. It is a promising approach to the extensive utilization of steel slag in cement industry.

Compressive Strength and Microstructure Properties of Alkali-Activated Systems with Blast Furnace Slag, Desulfurization Slag, and Gypsum

This study investigates the effect of desulfurization slag (DS) and gypsum (G) on the compressive strength and microstructure properties of blast furnace slag-(BFS-) based alkali-activated systems. DS is produced in a Kambara reactor process of molten iron produced in a steel production process. DS contains CaO, SiO2, Fe2O3, and SO3 and is composed of Ca(OH)2 and 2CaO·SiO2 as main compounds. In this investigation, the weight of BFS was replaced by DS at 5, 10, 15, 20, 25, and 30%. In addition, G was also applied at 9, 12, and 15% by weight of BFS to improve the compressive strength of the alkali-activated system with BFS and DS. According to this investigation, the compressive strength of the alkali-activated mixes with BFS and DS ranged from 14.9 MPa (B95D5) to 19.8 MPa (B90D10) after 91 days. However, the 28 days compressive strength of the alkali-activated mixes with BFS, DS, and G reached 39.1 MPa, 45.2 MPa, and 48.4 MPa, respectively, which were approximately 78.8 to 97.5% of that of O100 mix (49.6 MPa). The main hydrates of the BFS-DS (B80D20) binder sample were Ca(OH)2, CaCO3, and low-crystalline calcium silicate hydrates, while the main hydration product of BFS-DS-G (B75D10G15) binder was found as ettringite. The use of BFS-DS-G binders would result in the value-added utilization of steel slag and provide an environmentally friendly construction material, and contribute to a reduction of CO2 in the cement industry.

Mechanisms of ultrafine particle formation during coal combustion in a new swirl modification device

A new swirl combustion device was designed and enhanced, which realized the utilization of steel slag, achieved highly efficient and clean coal combustion, and simultaneously realized a fully elemental utilization of coal. The distribution laws of different sized particulate matter (PM) emission and the enrichment laws of elements in particles under diverse conditions (such as various excess air coefficients and different coal ratios) were systematically studied. The enrichments of PM under both non-staged and fuel-staged conditions were also investigated. The results indicated that fuel-staged combustion is more helpful in reducing PM emissions than non-staged combustion, and a suitable coal ratio is also beneficial for reducing PM emissions. The melted liquid steel slag drop captured the fly ash produced from pulverized combustion, thus reducing PM emission. The alkali metal elements (K, Na, and Mg), the trace elements (As and Ti), and S have an obvious enrichment tendency in PM1 and PM2.5. A different coal ratio under fuel-staged combustion has a significant influence on the enrichment of Al, Si, Ca, and Fe in PM1, whereas in PM2.5, PM4, and PM10, the effect of different coal ratios on the enrichment of each element is slight.

Corrosion evaluation of steel slag based on a leaching solution test

ABSTRACTSteel slag is alkaline in aqueous solution, and this is a typical feature for solid wastes that contain large amounts of basic oxides. Therefore, this parameter is used for solid waste hazard assessments. Special attention needs to be paid to the chemical parameters of steel slag to improve its comprehensive utilization, disposal, and storage. The corrosiveness of converter slag samples from different steel plants was evaluated according to the method stipulated by the Chinese national standard GB5085.1–007 to identify whether they would be classified as alkaline hazardous waste. The results showed that steel slag leaching solution had a certain corrosivity, and the pH value of the leaching solution increased with a decrease in the particle size of the steel slag and a decrease in temperature. However, the pH value of the short-term and long-term deposited slag leaching solution was not more than the standard limit value, and hence was not a hazardous waste. It was also found that the pH value (12.66 and 12.60) of the leachate of the grounded products of some of the steel slag was close to the pH of saturated Ca(OH)2 at 16°C. The measured pH value entered the pH range for a hazardous waste because it was obtained from the grinding of slag powder products. It was not in the original state of steel slag commonly produced by the steel slag industry. Therefore, it cannot be said that this pH directly indicated that the steel slag produced by these steel plants is hazardous waste. This study provides an analytical method that can be used as a basis for the safe storage and comprehensive utilization of steel slag.

Experimental evaluation of EAF ladle steel slag as a geo-fill material: Mineralogical, physical & mechanical properties

Despite of significant efforts in the last decades towards utilization of steel slag in the construction industry, steel slag stockpiling and landfilling operations do not seem to be declining in steel-producing countries. Use of steel slag as a construction material requires understanding of its engineering properties and development of a methodology to address its swelling potential. This paper focuses on the results of a series of laboratory tests (grain-size analysis, X-ray diffraction, specific gravity, compaction, maximum and minimum dry unit weight, direct shear, and long-term swelling tests) performed on samples of electric-arc-furnace ladle (EAF(L)) steel slag to assess its potential to be used as a geo-material. Direct shear test results indicated that the EAF(L) steel slag exhibits comparable frictional properties to angular crushed sand. Based on the leachate concentration levels from TCLP analyses, the EAF(L) steel slag tested was classified as Type III Solid Waste. The long-term, one-dimensional (1D) swelling test results showed continued volumetric expansion even after more than 16months of monitoring. Replacing 5–10% by weight of EAF (L) steel slag with Class C fly ash reduced the 1D swelling to negligible levels.

Influence of Pretreatment on the Free CaO in Steel Slag

An experimental program was carried out to investigate how to improve the characteristics of steel slag. Mainly the pretreatment methods of cooking and autoclave were used to detect such as free CaO content in the steel slag. The physical and chemical characteristics of steel slag were measured by X-ray diffraction (XRD) and fluorescence (XRF) analysis. The aim of improving the slag utilization is an important way to resolve large production problem, and then the research progress of steel slag utilization at home and abroad are recycled as raw material to be applied. By means of those ways to manage steel slag we have received the following conclusions: With the increase of cooking temperature the content of free CaO is gradually reduced. When temperature higher than 90oC the means could greatly reduce the free CaO content from about 7% wt. to less than 2.5% wt. in 3 h. By means of autoclave pressure upto 1.5MPa could greatly reduce the free CaO content from about 7% wt. to less than 3.2% wt. in 3 h. Through the study of the relevant of steel slag after pretreatment can effectively reduce the free CaO content in the steel slag, improving the stability of the steel slag is advantageous to the seven used in the construction field.

Research on mineral characteristics of converter steel slag and its comprehensive utilization of internal and external recycle

Converter steel slag is a vast amount of solid waste generated in the steelmaking process that has very low utilization rate in China and is usually deposited as waste. This paper investigates the physical and chemical characteristics of converter steel slag, as well as its comprehensive utilization of internal and external recycle. The results show that the mineral phases of converter steel slag mainly include dicalcium silicate (C2S), tricalcium silicate (C3S), RO phase and calcium ferrite (2CaO·Fe2O3) and so on, where the proportion of silicate phase is about 50%. Various mineral phases of converter steel slag show different morphologies in grey levels and shapes, and have great differences in Vickers hardness. The resource utilization of steel slag should follow the principle of internal and external recycle, which involves several technologies on recycle, separation and preparation of useful materials such as scrap steel, iron concentrate and steel slag powder. Five technologies, which include the volume stability technology, separation and recycling technology of iron and slag, efficient preparation technology of powder, the activation technology and application technology of steel slag powder in cement and concrete, are keys to achieve the efficient and bulk utilization of steel slag and their actions were presented by the relevant experimental researches as well.

Utilization of steel slag as aggregate in asphalt mixtures for microwave deicing

Under the dilemma of non-renewable natural resources shortage and environmental pollution issues, as a novel aggregate used in asphalt pavement, the application of steel slag is propitious to the improvement of the environment and the enhancement of economics. Meanwhile, steel slag has great potential for microwave heating as an excellent microwave absorbing material, which can contribute to remove the ice layer on the pavement. The primary objective of this work was to explore the feasibility of the usage of steel slag as the aggregate of asphalt mixtures for microwave deicing, and ascertain the most effective volume and particle sizes for partial replacement of conventional aggregate. The deicing mechanism of microwave heating pavement was firstly introduced. Then, the microwave heating capacity of steel slag with different particle sizes was tested and the surface elements distribution of steel slag was measured. In addition, the XRD test was conducted to analyze the material information of steel slag for its microwave heating capacity. Finally, the surface temperature, thermal conductivity and heating uniformity of asphalt mixture containing different steel slag content were tested. Results show that the particle sizes of 9.5 mm, 2.36 mm and 0.6 mm are considered as the most effective sizes. The thermal conductivity and microwave heating uniformity of asphalt mixtures basically decrease with the increase of steel slag content; while the surface temperature presents a contrary trend. Consequently, the suggested steel slag volume content is 40% and 60%; and the particle sizes of steel slag are selected as 9.5 mm, 2.36 mm and 0.6 mm. The comprehensive evaluation results on the supply sources, environmental hazard and cost of steel slag show great feasibility of its utilization in asphalt mixtures for microwave deicing, which is helpful to alleviate the supply shortage of natural aggregates and improve the safety of road traffic in winter.

Engineering properties and performance of asphalt mixtures incorporating steel slag

Lack of natural stone and costly expense of purchasing high-quality aggregate promote the utilization of steel slag. Asphalt mixtures incorporating basic oxygen furnace (BOF) steel slag as coarse aggregate were prepared and subsequently subjected to laboratory tests to determine the engineering properties of asphalt concrete. Results showed that the addition of steel slag into asphalt mixtures had high resistance to permanent deformation and moisture-induced damage. Steel slag included angular and rough textured particles that would enhance the interlocking mechanism and provide good mechanical properties. According to the laboratory results, a test road was constructed in 2012 by using three different types of asphalt mixtures as follows: stone mastic asphalt with BOF (SMA-BOF), dense-graded asphalt concrete with BOF (DGAC-BOF), and dense-graded asphalt concrete with natural aggregate (DGAC-NA). The rut depth of the SMA-BOF section was lowest among the three sites even though it was subject to high stress induced by braking, accelerating and turning vehicles. Surveys for pavement performance were conducted at scheduled intervals. The ride quality and the friction characteristics of both BOF sections performed as well as or better than the section constructed using natural aggregate. Field data indicated that steel slag could be used as a surface course aggregate in locations where traffic is expected to perform heavy braking and cornering maneuvers. No rutting, cracking, or other failures have been observed to any significant extent on the BOF sections since they opened to traffic throughout the three-year period. Test results suggest that the use of steel slag as coarse aggregate substitute in surface courses be technically appropriate.

Utilization of Steel Slag in Concrete as a Partial Replacement to Fine Aggregate

Concrete is largest produced material in the construction industry and as per WHO concrete is the largest consumed material by human beings after food and water. About 75% of the concrete is composed of aggregates and because of huge demand of concrete all over the world, availability of natural aggregates is becoming scarce. Civil engineers have always been looking for an alternative for the use of more eco-friendly and easily available materials as a replacement to conventional constituents in concrete. Concrete industry has always welcomed the use of various industrial waste materials as a replacement to these constituents since, otherwise such industrial waste need to be disposed in the form of landfills causing enormous amount of land pollution. This project presents the experimental investigation carried out to evaluate the effect of partial replacement of fine aggregate in concrete by steel slag which is waste product generated during the production of steel. The use of steel slag reduces the need of natural rock as constructional material, hence preserving our natural rock resources besides provides an environmental friendly option of concrete production. Steel slag mainly consists of calcium carbonate and is produced as a by-product of oxidation process in steel industry. The primary aim of this study is to evaluate the various properties of a concrete, obtained by partial replacement of fine aggregate by steel slag. In this research, apart from cement, fly ash and metakoalin (as a partial replacement to cement) were used as binding material. Five sample mixes were taken whose compression tests, tensile tests, sorptivity and water absorption tests were conducted. The mixes were obtained with 0, 30 and 40 percent replacement of fine aggregate by steel slag besides using different percentage replacements (25% of cement by fly ash in three trials, 15% and 10% cement by fly ash and metakoalin respectively in other two trials) of cement by pozzalonas. The experimental results were plotted and compared. It was observed that compressive and tensile strength increased with the increase in steel slag percentage upto to certain limit (30%). Increasing the percentage to 40% there was a sharp decline in magnitude of strength parameters and furthermore increasing metakoalin content had an effect of increasing strength. Capillary rise and water absorption increased with addition of steel slag and decreased with increase in metaloalin content.

Experimental Study on the Comprehensive Application of Steel Slag in Concrete

In this paper, the performance of steel slag composite cementitious material and the performance of steel slag concrete were studied, which provides reference for the comprehensive utilization of steel slag. The test shows that the activity of steel slag composite cementitious material with the specific surface area is greater than or equal to 400m2/kg to meet the use requirements; When the maximum content of coarse aggregate of steel slag was 25%, the volume stability of steel slag concrete was best. But when the content of steel slag powder was controlled within 30%, the concrete had good resistance to carbonation.

A review of steel slag usage in construction industry for sustainable development

Use of by-products from the steelmaking process can play an important role in achieving sustainable development. The available literature suggests that the use of iron and steel industry slags as mineral admixture or partial replacement of cement improves the microstructure of the concrete as well as its mechanical and durability characteristics. This paper reviews utilization of steel slag (SS) in the construction industry by considering current and possible future utilization fields, advantages of SS usage, and problems associated with its use. Strength and durability evolution of concretes or mortars containing SS in different ratios as aggregate or cement replacement material, combined use of ground granulated blast furnace slag with SS, and some relatively new fields of utilization of SS are also addressed. Improvements in and results of SS utilization in cement and concrete are discussed by addressing its beneficial effects. This article could help researchers to understand the recent developments in evaluation of SS in the construction industry.

The Application of Fuzzy Mathematical Method in the Evaluation of the Steel Slag Utilization

This study considered different influencing factors of the steel slag utilization including environmental benefit, economic benefit, technological adaptability and the scale of utilization, and based on the facors, fuzzy mathematical method was built to evaluate the steel slag utilization comprehensive benefits. Furthermore, this mode was applied in the benefit evaluation of a certain factory which is produced steel and iron slag cement, and “Good” grade was obtained. This mode provides scientific basis for utilization benefit of steel slag.

Process Improvement on the Gradation Uniformity of Steel Slag Asphalt Concrete Aggregate

A great amount of steel slag aggregate is used to prepare cement concrete and asphalt concrete in road construction However, the steel slag aggregate processed by the traditional aggregate production line is not uniform, which is not conducive to the full-size utilization of steel slag. Therefore, a new method of steel slag aggregate processing was proposed in this study in order to obtain the high quality steel slag aggregate with different specifications Experimental results indicated that the specifications stability of the steel slag was improved significantly when the steel slag was crushed by the combination equipments of jaw crusher and cone crusher. The screening efficiency and stability of the aggregate can be improved as the multi-level screening equipments were used into the production line. The wet rolling screen was also developed to remove the dust on the surface of aggregates. The specifications stability and pavement performance indexes of the steel slag aggregate produced by the new production line have been improved significantly compared to the steel slag aggregate produced by the traditional production line.

An Overview of Use of Linz-Donawitz (LD) Steel Slag in Agriculture

Slag generated from basic oxygen furnace (BOF) or Linz-Donawitz (LD) converter is one of the recyclable wastes in integrated steel plants. This paper deals with the present and possible use of LD slag in agriculture. At present, the amount of slag deposited in storage yard, leading to the occupation of farm land and serious pollution to the environment. Improving the slag utilization is an important way to resolve these problems. The physical and chemical characteristics of steel slag were analyzed and then the research progress of steel slag utilization in agriculture as fertilizer introduced. Due to increasing awareness of the environment, disposal, reuse of wastes without harming the environment has became a prime concern for the industry. The local availability of non conventional sources of plant nutrients and soil conditioners plays a vital role because of the non availability and higher price of environmental fertilizers. Therefore, this waste can be utilized for enhancing yield as well as solving the disposal problem and improve the environment.

Preparation and characterization of glass–ceramic under various sintering atmospheres

The iron rich glass–ceramics were prepared by cold pressing sintering method under various atmospheres. Microstructure evolution and crystalline phase transition of glass ceramics were investigated by field emission scanning electron microscopy and X-ray diffraction. The influence of sintering atmosphere on crystallization behaviour was carried out by differential thermal analysis experiment. The results indicate that the akermanite and gehlenite, in the form of spherical or granular, uniformly distribute in the glass matrix as samples sintered in N2 and CO (10vol% CO, 90vol% N2, 60mL/min) atmospheres. The corresponding nucleation and crystallization temperatures are both reduced by ~20°C. Moreover, the main mechanical properties of glass samples sintered in CO and N2 atmospheres are improved as compared with air ones, and the performance of samples sintered in CO (Bending strength 55MPa, micro-hardness 3.6GPa) is much better. This research is of special interest for the utilization of steel slag and energy saving.

Utilization of Steel Slag as Aggregates for SMA-13

A new method to make SMA is developed by using SBS modified asphalt when the coarse aggregate steel slag and the fine basalt aggregate are selected respectively. The Mix Proportion is 1#(16-9.5mm, steel slag):2#(9.5-4.75mm, steel slag):3#(3-4.75mm, basalt):4#(3-0mm, basalt):5# (mineral powder)=38%:36%:8%:8%:10%.The optimal asphalt content (OAC) is 6.4%. The mass percentage of steel slag is reached 74%. The costs of this kind of high quality road material can be saved because the amount of asphalt is not increased. Based on Marshall Stability and Splitting Strength test, it is shown that the Marshall stability of SMA is 10.6 kN, dynamic stability is 7800, and tensile strength ratio is 89.2%. All above test values are superior to the standards in China's traffic regulations. The water permeability coefficient of SMA is 65, which means that SMA has an excellence Wear-Resistant performance. Therefore, SMA can increase the road useful life and reduce the road maintenance costs.

Utilization of Steel Slag as Aggregates for OGFC-13

We propose a new method to make OGFC-13. By this method we select steel slag as coarse aggregate (whose diameter is bigger than 4.75mm) and limestone as fine aggregate, using the SBS modified asphalt to make OGFC-16. The Mix Proportion is 1#(19-13.2mm,steel slag):2#(13.2-9.5mm, steel slag):3#(9.5-4.75mm, steel slag):4#(4.75-0mm, limestone):mineral powder=13%:28%:45%:13%:1%. The optimal asphalt content (OAC) is 4.5%, the polyester fiber content is 0.3%, and the steel slag content reaches 86%. The increase of the amount of asphalt and polyester fiber doesn’t help to save costs. When the asphalt content is optimum, the run-off loss and Cantabro scattering loss satisfy the Chinese regulatory requirements. By Marshall Stability test, we find that the Marshall stability of OGFC-13 reaches 9.8kN, superior to China's traffic regulations. The water permeability coefficient of OGFC-13 is 37.0, which means that OGFC-13 has a strong water seepage performance. In a word, OGFC-13 made by our method can guarantee the driving security of the long-term use of the road and save a lot of road maintenance costs.

Characteristics and Utilization of Steel Slag in Road Construction

Presently, the rate of utilization of steel slag in Malaysia is rather too low compared to some advanced countries. Many studies focused on the better way to increase the usage of industrial by-products in order to ease disposal problems. Enormous quantities of steel slag were deposited in yards, causing environmental pollution. Like other metallurgical slags, steel slags exhibit a great potential to be used as aggregate in highway construction. The assessment and evaluation of this material should be based on environmental, economic and technical factors before it can be used in road construction. In terms of technical perspective, steel slags must met the required test requirements that are needed for natural aggregates used for similar purposes. The degree of slag utilization needs to be improved as an important measure to these problems. The physical and chemical properties of slag were reviewed and the various areas of its applications are highlighted. The principal setback of its use; volumetric instability which results from hydratable oxides can be checkmated through appropriate methods like aging and steam test. In order to sustain its uses, microstructure analysis that can identify any harmful materials present in it is suggested. There is also an urgent need of standard methods to assess its suitability as highway construction material.