Addition Of Steel Slag Research Articles

Effect of Steel Slag on Soil Fertility and Plant Growth

The effective utilization of steel slag, a byproduct produced in large quantities from the steel refining process, is an important issue. Because steel slag contains abundant mineral components, the effects of steel slag on soil bacterial biomass and plant mineral uptake were analyzed in this study. The soil pH increased in proportion to the amount of steel slag added. A lower concentration (0.2% to 1%) of steel slag addition did not change the bacterial biomass. However, a higher concentration of steel slag (above 1%) had a negative effect on bacterial biomass. A lower amount of steel slag (0.2% to 1%) addition in soil leads to increased mineral (Ca, Mg, and Fe) uptake and plant growth in Brassica rapa var. periviridis and Spinacia oleracea L. However, mineral uptake by the plants decreased when a large amount of steel slag (above 1%) was added to the soil. Low concentrations of steel slag (0.2% to 1%) in soil had positive effects on plant growth, mineral uptake of plants, and bacterial biomass.

Performance evaluation and environment risk assessment of steel slag enhancement for seawater to capture CO2

Major CO2 emitters are concentrated in coastal areas of China. The seawater with potential to capture CO2 was used as an absorbent and the addition of steel slag (SS) enhanced CO2 absorption by seawater. CO2 solubility in steel-slag-enhanced seawater was measured by an on-line chromatography apparatus, and the characterization analysis, thermodynamics, and kinetics were researched. CO2 solubility in seawater with a steel slag of 1.00 wt% increases by 64.27% relative to that in seawater, but is smaller than that in simulated-steel-slag-seawater (increasing by 29.86% relative to that in seawater with real steel slag). The results of XRD, TGA, IR and SEM-EDS show that Ca(OH)2 in the steel slag reacts with CO2 to form CaCO3. More quantity of CaO in simulated steel slag reacted with CO2 compared to real steel slag from XRF analysis. Increasing the concentration of steel slag and decreasing particle size of steel slag can also improve CO2 solubility and CO2 absorption rate. The steel slag and products after capturing CO2 are not hazardous waste and the steel slag can operate the solidification/stabilization of toxic metals. Steel slag can enhance CO2 absorption by seawater and perennially segregate CO2, providing CO2 capture and storage for coastal zones.

Study on Shear Strength Characteristics of Marine Silt Modified by Steel Slag

Modern coastal cities continue to expand to the sea, but the marine silt foundation has high water content and poor bearing capacity. Therefore, it is necessary to find economical and rapid ways to reduce the water content of the silt and improve the bearing capacity of the silt foundation. The steel slag is considered to be incorporated into silt to effectively reduce the moisture content of soil and improve the bearing capacity of the foundation due to its hard texture and strong water absorption capacity. In this paper, the shear strength characteristics of marine silt modified by steel slag were studied using an automatic triaxial instrument, as well as the relationship between steel slag incorporation and modified silt density. Experimental results showed that the incorporation of steel slag can effectively improve the shear strength of the silt. Besides, the influences of water content, steel slag incorporation, and confining pressure on the stress-strain curve characteristics and failure deviatoric stress of modified silt were also analyzed. The addition of steel slag increases the failure deviatoric stress of the silt. However, the increase of water content will weaken the effect of steel slag incorporation. The shear strength index of improved silt with different steel slag incorporation was compared with that of traditional soil, verifying the feasibility of its application in engineering construction.

Recycling industrial slags in production of fired clay bricks for sustainable manufacturing

Due to the production of industrial slags in massive amounts, there is a high demand for recycling these slags and avoiding their dumping in landfills. This article aims to recycle industrial slags in brick manufacturing and investigates the performance of fired clay bricks incorporating different kinds of industrial slags such as granulated blast furnace slag (GBS), ferrochromium slag (FCS), and steel slag (STS). For this purpose, two different dosages of slags (i.e., 10 and 20 wt % of clay) and two different firing temperatures (i.e., 1000 and 1100 oC) were considered. Various physical, mechanical, and durability tests were performed to evaluate the properties of bricks incorporating industrial slags. Results show that the compressive strength of the bricks incorporating industrial slags are well above the minimum compressive strength limits of bricks as per different building standards. The bricks incorporating industrial slag can be classified as load-bearing bricks for structural applications in accordance with the ASTM C469 standard. An increase in the porosity of bricks is observed with the addition of STS. However, reduced porosity is observed for bricks incorporating FCS and GBS than traditional bricks. Based on the water absorption and efflorescence test results, bricks incorporating industrial slags can be used as severe weather resistant bricks following ASTM C62 standard and slight efflorescence bricks per ASTM C67 standard. The amounts of heavy metals in the leachates of bricks are observed below the specified limits of the Environment Protection Authority. SEM images and EDS analysis of bricks are also supporting the results of this study. Based on the results, utilizing industrial slags in brick manufacturing can help recycle the abundant industrial wastes and develop the fired clay bricks with desired properties.

Coupling effect of steel slag in preparation of calcium-containing geopolymers with spent fluid catalytic cracking (FCC) catalyst

Spent FCC catalyst coupling with steel slag has been used to synthesize a new calcium-containing geopolymer binding material with excellent performance. The effect of the composition of the raw materials on the performance of the obtained samples has been investigated systematically. The results indicate that the compressive strength of the prepared geopolymers was increased with the addition of steel slag. This is due to the calcium-containing components in the steel slag, which possess higher reactivity compared to the pure chemical reagent in the alkaline activation environment, which is beneficial for the generation of N(C)-A-S-H amorphous gel (where N = Na2O, A = Al2O3, C = CaO, S = SiO2, and H = H2O) in the obtained samples. Meanwhile, the other components of steel slag would embed in the cementitious material as skeleton materials, which are conducive for the improvement of the compressive strength performance. In addition, the role steel slag plays in the geopolymerization reaction has been studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectrometry (FT-IR). Results indicated that the catalyst-derived geopolymer gel (N-A-S-H) coexisted with slag activated gel (C-S-H/C-A-S-H) in the binding matrix, which are the main phases in the geopolymer, and the development of better compressive strength is attributed to the formation of Ca-rich gel phases. These results highlight the feasibility of using spent FCC catalyst and steel slag as raw materials for the production of geopolymer binding material with enhanced compressive strength.

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.

Microwave heating of asphalt paving materials: Principles, current status and next steps

Microwave heating could contribute to the sustainability of several operations in the construction and maintenance of asphalt pavements. This paper aims at describing the current status of this technology and pointing out the next steps to promote its spreading in the asphalt industry. According to this investigation, asphalt binders are not susceptible to microwaves, but some types of aggregates remarkably promote the heating process. The addition of steel slag, metallic fibers or carbon nanomaterials can also enhance energy efficiency. Nevertheless, the lack of laboratory standardization and the need for full-scale equipment and projects can slow the use of this technology.

Effect of Steel Slag Aggregate on Pavement and Flame-Retardant Performance of Warm-Mixed Flame-Retardant Asphalt Concrete.

With the rapid development of tunnel construction, tunnel safety and the shortage of high-quality aggregates have concerned researchers so that this issue has become a research hot spot in the past few years. In the present study, we intended to prepare warm-mixed flame-retardant asphalt concrete using steel slag aggregate and evaluate its pavement and flame retardant performance. In this regard, the chemical composition and microstructure of the steel slag were studied using X-ray fluorescence analysis (XRF) and scanning electron microscopy (SEM). Then diverse pavement performances, including the dynamic stability, immersion Marshall, freeze–thaw splitting strength and low-temperature bending, were investigated for the warm-mixed flame-retardant asphalt concrete with steel slag aggregate. Moreover, a creative method of the flame spray gun combustion test was proposed to characterize the combustion degree and evaluate the flame-retardant performance of the asphalt concrete with steel slag. The experimental results show that the high-temperature and moisture stability performance are improved due to the addition of steel slag, however, the low-temperature performance is reduced for the warm-mixed flame-retardant asphalt concrete while it is still higher than the requirement value of the Chinese specification (GB/T 30596-2014). Meanwhile, the ignition temperature is increased and the ignition time is delayed for warm-mixed flame-retardant asphalt concrete because of the addition of steel slag. It is concluded that asphalt concrete with steel slag has excellent flame-retardant performance so that it is an appropriate choice for tunnel pavement.

Immobilization persistence of Cu, Cr, Pb, Zn ions by the addition of steel slag in acidic contaminated mine soil

Adding steel slag to the acidic contaminated mine soil can immobilize heavy metal ions, but immobilization persistence of the metal ions needs to be determined. In this study, dynamic column simulation experiments were set up to compare the immobilization persistence of Cu, Cr, Pb and Zn ions in original soil and with the addition of slag, lime or fly ash to the soil during a simulated 36-month of acid rain leaching. After adding slag and lime, the pH, organic matter content and cation exchange capacity of soil were significantly increased. Compared with the original soil, additions of slag and lime to the soil were able to persistently immobilize the metal ions, whereas fly ash additions had little effect. During simulation, the metal ion concentrations in the slag group leaching solution were essentially consistent with Standard IV for groundwater. The metal ions were immobilized to form instable hydroxides and stable fractions following adding slag to soil. The hydroxide could rerelease metal ions by acid rain leaching, part of which were re-immobilized into stable fractions by entering slag lattice and complexing with soil organic matter. Therefore, adding slag to soil can persistently immobilize metal ions for heavy metal-contaminated acidic mine soil.

Sustainable Recycling of Electric Arc Furnace Steel Slag as Aggregate in Concrete: Effects on the Environmental and Technical Performance

The aim of this research work was the evaluation of the feasibility to utilize industrial by-products, such as electric arc furnace steel slags, for sustainable concrete production. The paper evaluated the environmental and mechanical properties of steel slags and concrete, respectively. Specifically, the release of contaminants from steel slags was investigated by leaching test and the properties of fresh and hardened concrete were evaluated for a concrete mixture designed with a partial substitution (30%) of natural coarse aggregates with electric arc furnace steel slags. The results show that the concentrations of pollutants were lower than the legal limits imposed by the Ministerial Decree 186/2006 and the addition of steel slag can enhance the mechanical performance of concrete. The compressive strength of cubic specimens was also measured after different cycles of alternate wetting–drying. The steel slag incorporation results in a stiffness comparable to that of a traditional concrete. Overall, the mechanical and leaching characterization has shown that the reuse of electric arc furnace steel slags for sustainable concrete production is feasible and reliable.

Research on Basic Mechanical Properties of Large Scale Thermal Steel Slag Cement Concrete

The basic mechanical properties of steel slag concrete with waste thermal steel slag instead of the coarse and fine aggregates in concrete are studied and compared with the mechanical properties of ordinary concrete. The test results show that the addition of steel slag as coarse aggregate will enhance the compressive strength and flexural strength of concrete, and it will improve with the increase in the steel slag content. When steel slag is used as fine aggregate, the compressive strength of the steel slag concrete subjected to first increases and then decreases with increase in the steel slag sand content. To obtain better performance for the steel slag concrete, the suggested optimum content of steel slag sand as fine aggregate is 50%. Within. The addition of steel slag as fine aggregate can improve the flexural strength of concrete, and the flexural strength increases with the increase of the addition of steel slag sand. The steel slag concrete with the highest strength can be obtained when 100% of steel slag replaces the concrete aggregate, and the steel slag has good basic mechanical properties for the application of road engineering.

Inhibition mechanisms of steel slag on the early-age hydration of cement

Steel slag inhibits the early-age hydration of cement. However, its mechanism is still unclear. In this paper, the early-age hydration kinetics and the evolution of the solid phases, aqueous species and microstructures in a cement-steel slag composite binder are investigated to explore how steel slag inhibits the early-age hydration of cement. Two novel phenomena are found: (1) steel slag slows the depletion of gypsum and reduces the formation of ettringite, and (2) steel slag significantly inhibits the precipitation of CH and CSH. The results show that the addition of steel slag increases the Ca concentration in the pore solution, reduces the supersaturation of the pore solution with respect to CH and inhibits the nucleation and growth of CSH. Based on the above results, the retardation mechanisms of steel slag on the initial setting of cement paste are explained.

Analysis the use of steel slag as a replacement of natural aggregate in the asphalt concrete binder course (AC-BC) mixture

Aggregates are the largest component of the flexible pavement structure. The quality of the road is largely determined by the nature and type of aggregates used. Currently, the development of road infrastructure in Indonesia continues to experience increasing amount of natural aggregate use, so this will cause the availability of natural aggregate raw materials to continue to thin out. For that reason, an effort should be made to find alternatives to the use of natural aggregates, one of which is the utilization of steel slag. In this study, it will be examined the characteristics of the steel slag aggregates by referring to the 2018 Bina Marga specifications and the Marshall characteristic test method. This study used steel slag addition with variations of 0%, 50%, 80% and 100%. The results obtained in this study are that the value characteristics of the slag aggregate meet the standard specifications. The use of steel slag at 80% variation in coarse aggregate produces the best stability value which is equal to 2320,19 Kg. Overall, the use of steel slag can be an alternative to the use of natural aggregates. Moreover, steel slag can also be an alternative to an effort to reduce waste.

Application of powdered steel slag for more sustainable removal of metals from impaired waters

Using abundant and cheap steel slag for metals removal from water represents an opportunity to recover waste material from one industry as a resource for another. In this study, powdered steel slag which contains lime (CaO) leftover from the steelmaking process, was evaluated and benchmarked against the relatively expensive and energy-intensive chemical sodium hydroxide (NaOH) for the removal of cadmium (Cd), manganese (Mn), and zinc (Zn) from two different mine drainage waters. Unlike isotherm and kinetic studies that represent most previous work, this study evaluated metals removal under realistic simulated water treatment conditions (doses, mixing, contact times, etc.), bringing the material one-step closer to actual full-scale implementation. In the neutral pH water with lower metals concentrations, approximately four times more steel slag (400 mg/L) compared to NaOH (100 mg/L) was required to achieve >70% metals removal. In the acidic pH water with higher metals concentrations, steel slag was insufficient to raise the pH at reasonable doses (<1,000 mg/L) but was shown to reduce NaOH dosing requirements by 25% (600 to 450 mg/L) when used in combination with steel slag (600 mg/L). Like NaOH, steel slag addition facilitated metal precipitate formation but also provided relatively high specific surface area (7.6 m2/g) for metal adsorption, particularly for Mn, a promising finding for future work to evaluate sludge recycle. Water treated with steel slag was also found to be more amenable to 0.45 μm filtration than water treated with NaOH.

A review on utilization of steel slag in hot mix asphalt

Road construction involves large quantity of construction materials, primarily obtained from natural sources. Utilization of waste materials in construction activities can reduce burden on these natural sources. To achieve sustainable development, use of steel slag as a substitute to natural-aggregates has gained significant attention. Steel slag as aggregate has many well-known applications in road construction such as, hot mix asphalt, cement concrete mix, antiskid-layer, granular-base and subbase layers. This paper review development in various aspects of utilizing steel slag aggregate in dense graded hot mix asphalt. Properties of steel slag can significantly influence performance of roads. Chemical composition and physical and mechanical properties of steel slag have been reviewed in consideration of its suitability in asphalt mix. Findings from asphalt mix design studies indicate that, steel slag asphalt mix can be designed to satisfy both volumetric and mechanical properties. However, caution need to be exercised to ensure that addition of steel slag does not lead to undesirable change in performance of mix. Review of laboratory and field performance evaluation studies related to skid, moisture, fatigue and rutting failures are presented in the paper.

Suppression of arsenic release from alkaline excavated rock by calcium dissolved from steel slag.

Massive quantities of alkaline rocks are excavated from urban coastal and mountain areas to make underground spaces available for infrastructure projects; however, such excavated rock often releases arsenic. In the present study, arsenic release from the excavated rocks with steel slag was investigated using dialysis and batch leaching tests to understand where arsenic is immobilized and which components in the steel slag suppress arsenic release from the excavated rock. Dialysis test indicated that the addition of steel slag at 10 wt% could suppress arsenic release at a level greater than 66%. The total arsenic content in the steel slag did not increase as compared with that before the test. Sequential extraction analysis indicated that the arsenic released during the dialysis test is mainly derived from arsenic fraction 1 (nonspecifically bound) due to the higher amount of this arsenic fraction in the excavated rock with the steel slag. Moreover, the steel slag extract could suppress arsenic release from the excavated rock and remove the arsenic from aqueous solution. The pH dependence test further indicated that the arsenic immobilized by the steel slag extract was stable under alkaline pH conditions. The levels of arsenic release decreased with increasing calcium release from the steel slag regardless of the type of excavated rock with an alkaline pH and were particularly seen at calcium released > 500mgkg-1. These results indicate that the arsenic immobilization could be occurred not on the surface of steel slag, but on the excavated rock, and the calcium dissolved from the steel slag regulates the behavior of arsenic release from the surface of excavated rock. The findings of the present study suggest that the steel slag could be utilized to enable the reuse of excavated sedimentary and metamorphic rock of alkaline pH for the control of arsenic release.

Using Steel Slag for Stabilizing Clayey Soil in Sulaimani City-Iraq

The clayey soils have the capability to swell and shrink with the variation in moisture content. Soil stabilization is a well-known technique, which is implemented to improve the geotechnical properties of soils. The massive quantities of waste materials are resulting from modern industry methods create disposal hazards in addition to environmental problems. The steel industry has a waste that can be used with low strength and weak engineering properties soils. This study is carried out to evaluate the effect of steel slag (SS) as a by-product of the geotechnical properties of clayey soil. A series of laboratory tests were conducted on natural and stabilized soils. SS was added by 0, 2.5, 5, 10, 15, and 20% to the soil. The conducted tests are consistency limits, specific gravity, hydrometer analysis, modified Proctor compaction, swelling pressure, swelling percent, unconfined compressive strength, and California Bearing Ratio (Soaked CBR). The results showed that the values of liquid limit, plasticity index, optimum moisture content, swelling pressure, and swelling percent were decreased when stabilized the soil. However, the values of maximum dry density, unconfined compressive strength, and California bearing ratio were increased with the addition of steel slag with various percentages to the clayey soil samples. The steel slag was found to be successfully improving the geotechnical properties of clayey soils.

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.

Comparison of The Effect of Steel Slag Usage As a Fine Aggregate Against Compressive Strength And Flexture on Reinforced Concrete With Normal Concrete (Experimental Study)

One key element in that development is concrete. The basic ingredients of concrete is a mixture of cement, water, fine aggregate and coarse aggregate, while the concrete using steel reinforcement called reinforced concrete. The times in the era of rapid globalization have resulted in increasing number of second-hand goods / waste can be a problem for the existence of life, one of which is the existence of waste steel slag. To that end, much has been done in order to recycle in order to overcome the problem of the existence of this waste. One way is to capitalize upon such waste for purposes that could be used. In this study, the steel slag is used as a substitute or substitutes in normal concrete mix. Variations addition of steel slag at normal concrete to determine the compressive strength and flexural strength better and is expected to improve the quality of the concrete form of the compressive strength and strong bending. The variation of the addition of steel slag used was 0%, 15%, 25%, and the testing was done by the compressive strength and flexural strength. From the test results obtained by the resulting increase in the value of the slump, the increase in the compressive strength and increased compressive strength lentur. The increase in the capacity of steel slag respectively 11.91% and 20.35%, of normal concrete. Whereas the increase in the flexural strength of steel slag substitution respectively 16.62% and 31.18% of normal concrete. Therefore, if conducted further research it is better grades of steel slag enlarged variation of more than 25% in order to be used as a substitute. Continued research for high quality concrete can be done by mixing a solution that can increase the holding capacity of steel slag with other concrete constituent materials.

Process characteristics of catalytic thermochemical conversion of oily sludge with addition of steel slag towards energy and iron recovery

The improper disposal of oily sludge and converter steel slag can be of great environmental concerns, herein, we proposed an innovative methodology by coupling the catalytic thermochemical conversion of oily sludge with the high-temperature reduction of steel slag, where the gas energy and iron resources can be recovered simultaneously. It was found out that the gas yield, iron reduction efficiency, as well as the carbon conversion, were positively correlated with the temperature, the amount of steel slag added and slag particle fineness. With the addition of steel slag, the carbon conversion increased from 76.6 % to 90.1 %, and the iron reduction efficiency increased from 38.5 % to 70.6 %. The phase and microstructure characterizations revealed that the iron-bearing phases (RO phase, Ca2Fe2O5) in steel slag were reduced into metallic iron by pyrolytic gaseous intermediate products (600−800 °C) and solid char (800−1000 °C). The in-situ reduced iron particles in turn acted as an efficient catalyst for cracking/reforming reactions, resulting in remarkable fuel gases, i.e. H2, CO evolution. Hence, the reduction of steel slag and the catalytic cracking/reforming of oily sludge were both enhanced. Furthermore, the technical-economic analysis in terms of material and energy balances was performed. It revealed that the proposed process was favorable for energy recovery and high added material production.