Steel Sludge Research Articles

The Application of Converter Sludge and Slag to Produce Ecological Cement Mortars.

The paper presents an analysis of the effective use of a mixture of steel sludge (S1) and slag (S2) from the converter process of steel production for the production of cement mortars. Metallurgical waste used in the research, which is currently deposited in waste landfills and heaps near plants, posing a threat to groundwater (possibility of leaching metal ions present in the waste), was used as a substitute for natural sand in the range of 0-20% by weight of cement (each). The obtained test results and their numerical analysis made it possible to determine the conditions for replacing part of the sand in cement mortars with a mixture of sludge and slag from a basic oxygen furnace (BOF) and to determine the effects of such modification. For the numerical analysis, a full quadratic Response Surface Model (RSM) was utilized for two controlled factors. This model was subsequently optimized through backward stepwise regression, ensuring the inclusion of only statistically significant components and verifying the consistency of residual distribution with the normal distribution (tested via Ryan-Joiner's test, p > 0.1). The designated material models are helpful in designing ecological cement mortars using difficult-to-recycle waste (i.e., sludge and converter slag), which is important for a circular economy. Mortars modified with a mixture of metallurgical waste (up to 20% each) are characterized by a slightly lower consistency, compressive and flexural strength, and water absorption. However, they show a lower decrease in mechanical strength after the freezing-thawing process (frost resistance) compared to control mortars. Mortars modified with metallurgical waste do not have a negative impact on the environment in terms of leaching heavy metal ions. The use of a mixture of sludge and steel slag in the amount of 40% (slag/sludge in a 20/20 ratio) allows you to save 200 kg of sand when producing 1 m3 of cement mortar (cost reduction by approx. EUR 5.1/Mg) and will also reduce the costs of the environmental fee for depositing waste.

Analyzing the Impact of Annealed Steel Sludge Doses on the Physicochemical Properties of Biochar Obtained from Waste Date Palm Frond

Large quantities of date palm frond waste generated from the pruning process are accumulated or burned in burn barrels, harming the environment and having very little economic value. However, because of the lack of data revealing the characteristic magnetic properties of biochar derived from date palm fronds, further research on low-cost and sustainable strategies could offer a new composite material and serve to extend the way for novel applications. In this study, we prepared biochar derived from palm fronds via pyrolysis under a limited-oxygen atmosphere at a lower temperature of 300 °C for 2 h. We introduced a facile strategy for the production of magnetic biochar with various doses of annealed steel sludge material via ball milling. Various amounts of annealed steel sludge material (5%, 15%, and 25% w) were added to date palm frond biochar, and the obtained product was fabricated by ball milling. The physicochemical characteristics of the magnetic biochar composite were subsequently analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) spectroscopy, and UV-vis spectroscopy. Our findings showed that the ball milling method is a successful step for producing date palm fronds with magnetic biochar material possessing rough and packed pores, as shown by SEM. XRD patterns assumed the existence of magnetic phases of iron oxide (magnetite (Fe3O4), hematite (α-Fe2O3), and maghemite (γ-Fe2O3) at different generated peaks. FTIR outputs exhibited the abundant presence of various oxygen-containing functional groups (- COOH and -OH) on the surface of magnetic biochar material, which help to create chemically reactive sites to adsorb potential surrounding species. The UV spectra showed a noticeable enhancement of the optical properties of the magnetic biochar with an increase in the sludge dose for light absorption in the visible region from wavelengths of 400 – 700 nm . This result signifies the synthetic optimization and potential application of magnetic biochar materials for composites that could be employed in targeted uses including soil amendment, water remediation and energy applications.

Effect of Bamboo Charcoal with Earthworms on the Form and Bioavailability of Heavy Metals in Steel Sludge

Effect of Bamboo Charcoal with Earthworms on the Form and Bioavailability of Heavy Metals in Steel Sludge

A novel lignin-steel sludge composite for dyes adsorption from water: Surface functionalities and structural alteration mechanisms

The study focuses on fabricating and utilizing a lignin-steel sludge magnetic carbon composite (SLNa) to efficiently remove two dyes from an aqueous medium. The SLNa composite was fabricated through a simple two-step strategy involving the activation and thermal treatment of lignin and steel sludge. The SLNa possessed lignin and steel sludge starring properties, viz. abundant surface functionalities, graphitic carbon matrix, and magnetic characteristics. The synergistic combination of lignin and steel sludge resulted in composite's high adsorption potential for Methylene Blue (MB; 153.92 mg/g) and Acid Orange 7 (AO7; 64.84 mg/g) in batch mode. Additionally, the rapid adsorption kinetics and effective dye removal for MB (> 99 %) and AO7 (72 %) from simulated effluent revealed the potential of fabricated adsorbent for water remediation. Furthermore, the composite's applicability for continuous adsorption was also evaluated through a series of dynamic flow experiments using fixed-bed column systems. The demonstrated efficacy of SLNa, viz., 48.18 and 15.00 mg/g for MB and AO7, respectively, at high adsorbent loading and lower dye concentrations, highlights its potential for scalable water treatment applications. Thus, the versatility and effectiveness of the novel composite underscore its potential for practical application in both batch and continuous water remediation processes.

Optimizing Mix Proportion of Geopolymer Concrete with Steel Sludge - A Sustainable Approach

As the construction industry is moving towards sustainable infrastructure, the need for green construction materials has gained importance in current scenario. Geopolymer concrete is considered to be an alternate to conventional concrete with cement as cement production is considered to emit more greenhouse gases into the atmosphere. This work has still raised the sustainable part of the geopolymer concrete by using steel sludge generated from automobile industry as partial replacement for fine aggregate. The experimental results were designed using fractional factorial design. The results were analysed for statistical integrity with ANOVA. It has been observed that the maximum compressive strength achieved with steel sludge up to 30% replacement is 48 Mpa with flexural strength of 5.16 Mpa and split tensile strength of 4.6 Mpa. Optimisation was done to find the proportion that gives maximum strength and it was ascertained with experimental validation. XRD and SEM analysis were carried out for studying the microstructure and reaction products formed in the process.

Research on Biomass Waste Utilization for Synergetic Reduction of Stainless Steel Sludge and Zinc-Containing Dust

Research on Biomass Waste Utilization for Synergetic Reduction of Stainless Steel Sludge and Zinc-Containing Dust

Improving heavy metal removal efficiency from steel sludge: Application of the coupled ultrasonic-bioleaching treatment

<p>This study assessed the efficiency of Fe, Al, Ni and Sr removal from the steel sludge using the coupled bioleaching with Thiobacillus thiooxidans and ultrasonic waves. Growth conditions were optimized using the surface response method. The bacterium was adapted successively to three heavy metal-containing solutions with different concentrations of 100, 200, and 300 mg/ml. Samples were exposed to ultrasonic waves at frequencies of 30, 60 and 90 kHz and durations of 20, 30 and 40 min for two weeks. The highest Fe removal efficiency of 98.45% was obtained using the T. thiooxidation, wave frequency of 30 kHz for 40 min, and pulp density of 100 mg/ml. The maximum removal efficiency was found to be 99.74% for Al under a wave frequency of 90 kHz for 20 min and a pulp density of 300 mg/ml, approximately 100% for Ni under a wave frequency of 30 kHz for 20 min and a pulp density of 300 mg/ml, and 98.45% for Sr under a wave frequency of 90 kHz for 20 min and a pulp density of 300 mg/mL. Results showed that the removal efficiency of Ni and Al bioleaching improved significantly (P <0.05) under the ultrasonic irradiation while the removal efficiency of Fe and Sr remained statistically unchanged (P> 0.05) with and without the application of ultrasonic waves.</p>

Effects of electric arc furnace slag powder and fly ash within ternary waste blend on performance of concrete

Recently, research on utilising industrial and natural waste has advanced owing to their environmental concerns, including soil and groundwater contamination. Most such waste possess zero or low commercial value, yet it is stored, occupying large storage yards. Iron and steel factories and quarries worldwide produce large amounts of waste annually. This study used three types of steel mill waste (electric arc furnace slag powder, fly ash and steel sludge and natural waste from quarries limestone dust, marble dust, and recycled glass powder) as supplementary cementitious materials with the aim of producing an economical and environmentally friendly ternary waste binder. To determine the appropriate waste blend compounds of mixes, the study was conducted in three stages. First, waste mortars were used to mix, tests of mortars properties were conducted, and the properties of the mix were compared with those of a control mortar mix. Second, concrete was mixed from the waste blend with the most suitable properties. Finally, durability tests on the concrete were performed. Ternary residue having 4.5% SP, 10% FA, and 4.5% SS with 18% replacement of cement and that having 3.75% SP, 7.5% FA, and 3.75% LD with 15% replacement of cement achieved the requirements of concrete and improved the compressive strength and durability towards sulfate and chloride attack, including impermeability and resistance.

Phenol removal by activation of persulfate using magnetic carbon generated from sludge and steel converter slag

We obtained the best sample of Steel Sludge Carbon-Sludge Carbon (SCS@SC0.5–800 °C), which was subsequently used as a catalyst to activate persulphate for the removal of phenol. The batch experimental results illustrate the phenol removal efficiency reached 98.8% and the constants were 0. 25515 min−1 in the optimal SCS@SC0.5–800 °C/persulfate system (SCS@SC0.5–800 °C = 0.4 g/L; persulfate = 2 mM; phenol = 20 mg/L; pH=7). Increasing the reaction temperature increases the effectiveness of the system in removing phenol, and cations have a slight inhibitory effect on the removal of phenol from the system. Repeatability tests showed that after the third cycle, the phenol removal rate decreased from 88.6% to 65.2%, and the kobs decreased from 0.12567 min−1 to 0.03105 min−1. These results may be explained by the fact that active ingredients such as Fe0 are constantly removed from the solution, reducing the efficiency of the degradation process. The removal mechanism suggests that phenol is enriched on the graphitic carbon surface and subsequently degraded by leaching Fe2+-activated persulfate to produce free radicals. This study details the preparation of optimal samples of this new green catalyst and broadens the scope and potential of the catalyst for practical applications.

Optimization of Briquette Manufacturing Conditions Using Steel Sludge

Optimization of Briquette Manufacturing Conditions Using Steel Sludge

Hydrometallurgical Recovery of Iron, Nickel, and Chromium from Stainless Steel Sludge with Emphasis on Solvent Extraction and Chemical Precipitation

Stainless steel has a variety of applications nowadays because of its mechanical strength and corrosion resistance. The large-scale machinery made up of stainless steel has an outstanding performance and endurance for manufacturing industries. However, stainless steel scraps accumulate with a lubricant to form sludge during the operation. To reduce the environmental hazards caused by sludge, this research attempts to construct a hydrometallurgical process to recover iron, nickel, and chromium from the sludge. The experiments could be divided into four parts. First, calcination was adopted to remove the oil and water content. The factors that have impacts on the leaching efficiency, such as the type of acid and the calcination temperature, were investigated in the second part. It was optimal that the sludge was calcined at 300 ℃ for 8 h and leached by 4 mol/L HCl. The results revealed that the leaching percentages of iron, nickel, and chromium were 97.6%, 98.1%, and 95.7%, respectively. In the two-stage solvent extraction procedure, Fe(III) could be efficiently recovered by using 0.1 mol/L bis(2-ethlhexyl) phosphate (D2EHPA) at pH 1.5 with an Aqueous/Organic ratio of 1 over 10 min. The results indicated that the extraction percentage of Fe(III) was beyond 99%. Eventually, the recoveries of nickel and chromium were respectively 99.5% and 75% through chemical precipitation.

Preparation of Adsorbents by Pyrolysis of Sludge Mixed With Steel Slag and Study on Adsorption of Chromium Ions in Water

In this study, the dewatered sludge from the sewage plant and the open-hearth steel slag of the steel plant are used as raw materials. As two wastes, they were mixed and pyrolyzed to prepare a composite absorbent. Further, the adsorption mechanism of the adsorbent to chromium ions in the sewage is explored. The pyrolysis reaction behavior of sludge mixed with steel slag was studied by the thermogravimetric analysis technology. SEM, BET, and XPS were used to analyze the specific surface area, pore size distribution, and pore structure characteristics of pyrolysis products, respectively. Moreover, a comprehensive analysis of the adsorbent was carried out for the adsorption mechanism of hexavalent chromium ions. The results show that the addition of steel slag promotes the pyrolysis of the sludge in each stage. When the content of steel slag is 80%, the increases of reaction rate are the most obvious with the largest increase of weight loss rate in each stage. The SEM results show that the enrichment of sludge on metal oxides is enhanced in the high-temperature range (600–700°C). Besides, when the content of steel slag is 40–60%, the mixture’s growth rate of the specific surface area can reach 600% and the growth rate of total pore volume can reach 350% (the situations of sludge as the baseline). Regarding the measurement of Cr(VI), the adsorption rate of the steel-slag solution is 50.93% and that of the sludge solution is 69%. However, the adsorption rate can be increased to 95% when the steel slag and sludge were mixed as an adsorption solution. In conclusion, the adsorption mechanism of Cr(VI) by additives is controlled by both physical and chemical processes. The present study provides a theoretical basis and technical support for the scientific and reasonable utilization of sludge and steel slag.

Properties of aerated concrete with steel sludge waste from automobile industry

Research on new materials based on the current construction scenario for different applications has led to development of many special concretes. Lightweight concrete is one such type which has many advantages like reduced dead load, thermal comfort and economy in construction. But the major disadvantage that has restricted the popularity of its use is the low compressive strength. This work is based on developing a lightweight concrete by way of making it a sustainable construction material developed from waste steel sludge generated in automobile industry. The compressive and flexural strength of this concrete was 22 MPa and 1.8 MPa respectively. Durability properties were also studied proving that the material can be used in construction. Microstructure investigations were done to analyze the porosity of the concrete and the products formed during the hydration reaction. The total experimental sequence was designed using response surface methodology of central composite design and the experimental results were analyzed by ANOVA to find the significance of the parameters. Response surface graphs and optimization was obtained as a result of the experimental results.

Utilization of metallurgical waste for the preparation of photocatalytically active composites based on ZnO–graphene oxide

Steel sludge was used as a source of technical zinc oxide (ZnOL) for the preparation of ZnO–graphene oxide (ZnOL–GO) composite with photocatalytic effects. The specific surface of the manufactured product was determined by SBET method, and structural analysis was performed by FTIR spectroscopy. The photocatalytic efficiency of the ZnOL–GO composite was studied using optical methods (UV–Vis spectroscopy, photoluminescence). The obtained results were confronted with a model composite prepared from pure components. It was found that the prepared ZnOL–GO composite showed excellent photodegradation activities against the azo dye Acid Orange 7 in comparison with the model composite. The presence of other metal oxides in ZnOL in conjunction with GO causes a significant increase in the photocatalytic efficiency of the prepared composite material, which can be explained by the modification of the electronic structure and more efficient separation of charge carriers. The obtained results show new possibilities in the field of processing and further use of metallurgical waste.

ОСОБЛИВОСТІ ВИКОРИСТАННЯ ПРОМИСЛОВИХ ТЕХНОГЕНИХ ВІДХОДІВ В ГАЛУЗІ БУДІВЕЛЬНИХ МАТЕРІАЛІВ

Another aggravation of the ecological and economic situation in Ukraine makes it necessary to develop new efficient technologies for processing and use of industrial man-made waste from the heat and chemical industries. Such technologies should ensure their maximum degree of use in the production of high-quality efficient construction products. The choice of technology for the preparation, processing and use of industrial waste depends on such factors as their chemical-mineralogical and particle size distribution and method of production. Although such wastes are mostly used as aggregates, their overall use remains low. The share of their use in the manufacture of construction products is 5-12%, and the manufacture of products requires additional energy consumption. The paper considers the possibility of using industrial waste not only due to their activation, but also due to the use of their multifunctional properties. When the inactivated ash is introduced into the concrete mixture, it increases the plasticity of such a mixture and at the same time the microfiller promotes the formation of a stronger contact zone by increasing the degree of crystal chemical similarity of tumors. Excessive amounts of ash in ash-containing materials lead to increased porosity and reduced rate of accumulation of strength over time, which impairs performance, including frost and corrosion resistance. Large-scale use of phosphogypsum is hindered by its specific features: physical state, high humidity, the presence of phosphoric and sulfuric acid and water-soluble harmful compounds of phosphorus and fluorine. Therefore, before using phosphogypsum, it is necessary to remove or neutralize harmful impurities and reduce the concentration of acid residues. Harmful impurities can be bound and acid residues can be neutralized by adding quicklime to the solution. Lime simultaneously neutralizes acids and binds water-soluble harmful impurities. The most effective method of using phosphogypsum, fly ash and fine powders of steel sludge SHH-15 is the integrated use of such waste, resulting in a complex metal-ash-phosphate binder (MАРВ).

Metals droplet assembling mechanism during carbon reduction of stainless steel pickling sludge

Abstract Stainless steel sludge contained large amounts of heavy metals like Cr. These sludge are now mainly disposed by landfills, occupying a large amount of land and polluting the environment. The objective of the paper is to explore the synergistic reduction of Cr and Fe, and the phase transition during the process. Find out the forming condition of Fe–Cr–C alloy. Study the growth and migration trend of low melting point Fe–Cr–C droplets. Thus we could find a way to recover heavy metals from the sludge with less energy and make the tailings harmless to the environment. Through X-Ray Diffraction and Energy Dispersive Spectrometer analysis, the results showed that chromium mainly presented in the FeCr2O4 phase before it was reduced, and the reduction product was Fe–Cr–C metal carbide. By observing samples reduced at different temperatures with metallographic microscope, it could be found that the melted metal carbides flowed under the surface tension to form larger droplets at temperatures around 1250 °C. On the basis, the method of semi-melting sludge reduction at a temperature of 1275 °C which was lower than the existing method of 1350 °C, was first proposed. Under this condition, the average diameter of the obtained Fe–Cr–C particles was 2.7 mm, which was easy to separate from the tailings. The yield of Fe and Cr reached 86.7% and 71.3% respectively, which means 0.22 ton of metal particles could be recovered per ton of sludge, and could be used in steel making. The obtained non-magnetic tailings with a Cr content of less than 0.04% was harmless, and the remained magnetic powder could be used as a nucleating agent for the reduction of sludge.

Properties of concrete containing electric arc furnace steel slag and steel sludge

This paper presents an experimental study concerning the properties of concrete prepared with waste products generated from steel industry, namely electric arc furnace steel slag (EAFS) and steel sludge. A series of mixes with varying contents of EAFS or steel sludge up to 20% as cement replacement was prepared to assess several crucial aspects, such as workability, compressive strength, initial surface absorption test (ISAT), water absorption, and heavy metals of leaching test. Alteration on concrete microstructure was studied to determine the roles and the interaction mechanism with cement matrix. The experimental outputs signified that 10% replacement of EAFS and steel sludge with sufficient workability enhanced the compressive strength, especially in later age of concrete strength development. Both initial surface absorption and water absorption capacities were enhanced at similar percentage of replacement of EAFS and steel sludge, thus minimising permeability properties. Leaching test outcomes revealed that the inclusion of the two steel by-products into concrete did not pose any threat to the environment. The morphology evidence showed that concrete containing EAFS and steel sludge appeared denser as compared to normal concrete. Therefore, concrete containing EAFS and steel sludge possesses high potential for application in light of green and advanced concrete technology.

Characterisation and utilization of steel industry waste sludge as heterogeneous catalyst for the abatement of chlorinated organics by advanced oxidation processes.

Catalytic advanced oxidation processes (AOPs) utilising UV irradiation have been reported to be highly efficient for the degradation of recalcitrant compounds. The focus of present study was to evaluate the potential of steel industry waste as an alternative to homogenous iron salts often used in AOPs. Iron rich sludge from effluent treatment plant (ETP) of a steel industry was subjected to acid washing and acid washing followed by calcination before using as catalyst for the oxidative removal of chlorinated organics present in synthetic and simulated bleaching effluents. The maximum total organic carbon removals of 64% and 25% from 4-chlorophenol solution and simulated pulp bleaching effluent, respectively were observed during photo-catalytic oxidation with acid washed steel sludge at stoichiometric H2O2 dose after 2 h reaction (catalyst dose = 1 g/L, and pH = 4.4). Low iron leaching (<2%) was observed from the catalyst even in acidic conditions and it could be reused twice without significant loss of catalytic activity.

Parameters affecting the formation mechanisms of dioxins in the steel manufacture process

With the implementation of the new national standards in the steel industry, dioxins (polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs)) emission and control have attracted more and more attention in China.The PCDD/Fs levels and signatures of nine steelmaking materials and by-products were experimentally analysed and compared, including five kinds of steelmaking fly ash (sintering fly ash, basic oxygen furnace fly ash, electric arc furnace fly ash and two kinds of blast furnace fly), three kind of steel sludge (continuous casting sludge, hot rolling sludge and cold rolling sludge) and sintering raw material. Dioxin formation from the sintering fly ash was highest of all 9 materials. Furthermore, highly chlorinated PCDD/Fs homologues were abundant in that sample, while the profiles were contrary to those of other materials. More importantly, the entire isomer signatures of all 61 samples were analysed, involving various materials, temperatures, oxygen levels, particle size and inhibitors, with special emphasis on those congeners associated with chlorophenol precursor routes, as well as seventeen 2,3,7,8-substituted PCDD/Fs. Strong correlation was found among seven PCDD-congeners of CP-route. The analysis of the molecular structure of these congeners revealed that 2,4,6/2,3,5-trichlorophenol may act as a precursor to form all those PCDD-congeners by condensation. In addition, the influence of various factors (temperature, oxygen level, particle size, inhibitors addition etc.) on the relative importance of CP-route congeners and 2,3,7,8-substituted congeners was discussed, with the goal of shedding more light on the mechanism of PCDD/Fs-formation.

Improvement of Clayey Soil with Lime and Industrial Sludge

Industrial waste generation has reached up to millions of tons yearly. One way to solve the problems of the large accumulating amount of waste could be to incorporate it into the soil; thus, finding a way for the use of industrial waste could be a quest for soil improvement studies. Industrial sludge in certain pozzolanic form reacts with soil and possesses cementitious properties. This paper illustrates the utilization of lime, steel and copper sludge in improvement of high plasticity clayey soil. The influence of stabilizer type, different curing times and various ratios of lime to sludge are evaluated by Atterberg limits, standard proctor compaction, unconfined compressive strength and unconsolidated undrained strength in triaxial test. The test results show that adding lime and sludge results in an increase in maximum strength. Moreover, the strength of soil increases with the increase of curing time. Utilizing stabilizers also influences plasticity index and compaction parameters. Finally, the results demonstrate that steel sludge has better performance than that of copper sludge in term of strength development.