Blast Furnace Sludge Research Articles

Removal of bromophenols from water using industrial wastes as low cost adsorbents

A comparative study of the adsorbents prepared from several industrial wastes for the removal of 2-bromophenol, 4-bromophenol and 2,4-dibromophenol has been carried out. The results show that maximum adsorption on carbonaceous adsorbent prepared from fertilizer industry waste has been found to be 40.7, 170.4 and 190.2 mg g −1 for 4-bromophenol 2-bromophenol and 2,4-dibromophenol, respectively. As compared to carbonaceous adsorbent, the other three adsorbents (viz., blast furnace sludge, dust, and slag) adsorb bromophenols to a much smaller extent. This has been attributed to the carbonaceous adsorbent having a larger porosity and consequently higher surface area. The adsorption of bromophenols on this adsorbent has been studied as a function of contact time, concentration and temperature. The adsorption has been found to be endothermic, and the data conform to the Langmuir equation. The further analysis of data indicates that adsorption is a first order process. A comparative study of adsorption results with those obtained on standard activated charcoal sample shows that prepared carbonaceous adsorbent is about 45% as efficient as standard activated charcoal in removing bromophenols. To test the practical utility of this adsorbent, column operations were also carried out. The results were found satisfactory in removing bromophenols by column operations. Therefore, the present investigations recommend the use of carbon slurry waste as inexpensive adsorbent for small scale industries of developing/poor countries where disposal of solid waste of various industries and proper treatment of polluted wastewater is a serious problem.

An overview of utilization of slag and sludge from steel industries

Significant quantities of sludge and slag are generated as waste material or byproduct every day from steel industries. They usually contain considerable quantities of valuable metals and materials. It is generally possible to recover some values by physical or chemical mineral processing techniques such as crushing, grinding, classification, hydrocyclone, magnetic separation, flotation, leaching or roasting. Transforming these solid wastes from one form to another to be reused either by the same production unit or by different industrial installation are very much essential not only for conserving metals and mineral resources but also for protecting the environment. This paper analyzes the characterization, beneficiation and utilization aspects of blast furnace flue dust, blast furnace sludge, LD sludge and LD slag generated at modern steel plants.

Adsorption of 2,4-D and carbofuran pesticides using fertilizer and steel industry wastes

The removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and carbofuran from aqueous solution was studied by using fertilizer industry waste (carbon slurry) and steel industry wastes (blast furnace slag, dust, and sludge) as adsorbents in batch. Adsorption was found to be in decreasing order: carbon slurry, blast furnace sludge, dust, and slag, respectively. Carbonaceous adsorbent prepared from carbon slurry exhibited the uptake capacity of 212 and 208 mg g −1 for 2,4-D and carbofuran, respectively at 25 °C and pH 7.5. Adsorption equilibrium, kinetics, and thermodynamics were investigated as a function of initial pH, temperature, and pesticide concentrations. Equilibrium data fitted well to the Langmuir equilibrium model in the studied concentration range of 2,4-D and carbofuran at all the temperatures studied. Two simplified models, including pseudo-first-order and pseudo-second-order kinetic models, were used to test the adsorption kinetics. Adsorption of 2,4-D and carbofuran on carbon slurry at 25, 35, and 45 °C could be best fitted in the pseudo-second-order kinetic model. Pore diffusion was confirmed as the essential rate-controlling step with the help of Bangham's equation.

Chemical and Mineralogical Characterization of Blast-Furnace Sludge from an Abandoned Landfill

Blast-furnace sludge is generated during the production of pig iron and is disposed of in the environment in large surface landfills. We investigated blast-furnace sludge samples of an abandoned landfill in order to determine its chemical and mineralogical nature and to evaluate some environmental hazards that may arise from this industrial waste. The mineralogical inventory, which was quantified by Rietveld refinement of XRD analyses using the fundamental-parameter approach, revealed that blast-furnace sludge is dominated by X-ray amorphous substances (with a mean of 590 g kg(-1)) including coke and (hydr)oxides of Fe, Si, Al, Zn, and Pb. Calcite (CaCO3) (136 g kg(-1)), dolomite (Ca,Mg[CO3]2) (14 g kg(-1)), quartz (SiO2) (55 g kg(-1)), kaolinite (Al2[OH]4Si2O5) (40 g kg(-1)), graphite (C) (27 g kg(-1)), and chemically not specified layered double hydroxides (28 g kg(-1)) were identified in almost all samples. Iron is present as magnetite (Fe3O4) (34 g kg(-1)), hematite (Fe2O3) (38 g kg(-1)), wuestite (FeO) (20 g kg(-1)) and alpha-iron (Fe0) (6 g kg(-1)). Chemically, blast-furnace sludge is dominated by C (190 g kg(-1)) and Fe (158 g kg(-1)) reflecting the process of pig-iron production. On the basis of total contents, environmentally problematic metals (including As) are Zn (32.6 g kg(-1)), Pb (10.3 g kg(-1)), Cd (81 mg kg(-1)), and As (129 mg kg(-1)). As the forested landfill is used by residents for leisure activities, the exposure assessment by pathway oral uptake of blast-furnace sludge particles by humans has to be critically evaluated, particularly as significant proportions of metals are acid-soluble. However, under the prevailing slightly alkaline pH values of the sludge (pH 7.6-9.2), the solubility of the metals is very low as indicated by low pore water concentrations. Currently, groundwater monitoring should be focused mainly on F- since the F- concentrations in the pore water of blast-furnace sludge are at high level (2.65-24.1 mg of F- L(-1)).

A comparative adsorption study with different industrial wastes as adsorbents for the removal of cationic dyes from water

Four adsorbents have been prepared from industrial wastes obtained from the steel and fertilizer industries and investigated for their utility to remove cationic dyes. Studies have shown that the adsorbents prepared from blast furnace sludge, dust, and slag have poor porosity and low surface area, resulting in very low efficiency for the adsorption of dyes. On the other hand, carbonaceous adsorbent prepared from carbon slurry waste obtained from the fertilizer industry was found to show good porosity and appreciable surface area and consequently adsorbs dyes to an appreciable extent. The adsorption of two cationic dyes, viz., rhodamine B and Bismark Brown R on carbonaceous adsorbent conforms to Langmuir equation, is a first-order process and pore diffusion controlled. As the adsorption of dyes investigated was appreciable on carbonaceous adsorbent, its efficiency was evaluated by comparing the results with those obtained on a standard activated charcoal sample. It was found that prepared carbonaceous adsorbent exhibits dye removal efficiency that is about 80-90% of that observed with standard activated charcoal samples. Thus, it can be fruitfully used for the removal of dyes and is a suitable alternative to standard activated charcoal in view of its cheaper cost.

Removal of 2‐fluoro and 2‐iodophenol from aqueous solutions using industrial wastes

A comparative study of the adsorbents prepared from several industrial wastes for the removal of 2‐fluorophenol and 2‐iodophenol has been carried out. The results show that maximum adsorption on carbonaceous adsorbent prepared from fertilizer industry waste has been found to be 35.3 and 235.3 mg g‐1 for 2‐fluorophenol and 2‐iodophenol, respectively. Compared to carbonaceous adsorbent, the other three adsorbents (viz., blast furnace sludge, dust, and slag) adsorb phenols to a much smaller extent. This has been attributed to the carbonaceous adsorbent having a larger porosity and consequently higher surface area. The adsorption of phenols on this adsorbent has been studied as a function of contact time, concentration and temperature. The adsorption has been found to be endothermic, and the data conform to the Langmuir equation. The further analysis of data indicates that adsorption is a first order process and pore diffusion controlled. A comparative study of adsorption results with those obtained on standard activated charcoal sample shows that prepared adsorbent is about 45% as efficient as standard activated charcoal and therefore, can be fruitfully employed for the removal of phenolic pollutants from wastewaters.

Sorption and desorption of iron–cyanide complexes in deposited blast furnace sludge

Blast furnace sludge is a waste originating from pig iron production and contains small amounts of iron–cyanide complexes. Leaching of iron–cyanide complexes from deposited blast furnace sludge into the ground water seems to be possible in principle. We investigated the sorption of the iron–cyanide complexes ferrocyanide, [Fe II(CN) 6] 4−, and ferricyanide, [Fe III(CN) 6] 3−, in 22 samples of deposited blast furnace sludge in batch experiments. Subsequently, desorption of iron–cyanide complexes was investigated using 1 M NaCl. Sorption in five samples was evaluated with Langmuir isotherms. The blast furnace sludge samples were neutral to slightly alkaline (pH 7.6–9) and consisted of X-ray amorphous compounds and crystalline Fe oxides primarily. X-ray amorphous compounds are assumed to comprise coke-bound C and amorphous Fe, Zn, and Al oxides. The experiments that were evaluated with Langmuir isotherms indicated that the extent of ferricyanide sorption was higher than that of ferrocyanide sorption. Saturation of blast furnace sludge with iron–cyanide complexes was achieved. Sorption of iron–cyanide complexes in 22 blast furnace sludge samples at one initial concentration showed that 12 samples sorbed more ferrocyanide than ferricyanide. The extent of sorption largely differed between 0.07 and 2.76 μmol [Fe(CN) 6] m −2 and was governed by coke-bound C. Ferricyanide sorption was negatively influenced by crystalline Fe oxides additionally. Only small amounts of iron–cyanide complexes sorbed in blast furnace sludge were desorbed by 1 M NaCl (ferrocyanide, 3.2%; ferricyanide, 1.1%, given as median). This indicated strong interactions of iron–cyanide complexes in blast furnace sludge. The mobility of iron–cyanide complexes in deposited blast furnace sludge and consequently contamination of the seepage and ground water was designated as low, because (i) deposited blast furnace sludge is able to sorb iron–cyanide complexes strongly, (ii) the solubility of the iron–cyanide-containing phase, K 2Zn 3[Fe II(CN) 6]·9H 2O, is known to be low, and (iii) a worst case scenario of the transport of iron–cyanide complexes within the blast furnace sludge deposit indicated strong retardation of the complexes within the next 100 years.

Methylphenols Removal from Water by Low-Cost Adsorbents

A comparative study on the adsorption of methylphenols on adsorbents prepared from several industrial wastes has been carried out. The results show that extent of adsorption on carbonaceous adsorbent prepared from fertilizer industry waste has been found to be 37.3, 40.5, 65.9, and 88.5 mg/g for 2-methylphenol, 4-methylphenol, 2,4-dimethylphenol, and 2,4,6-trimethylphenol, rspectively. As compared to carbonaceous adsorbent, the other three adsorbents viz. blast furnace sludge, dust, and slag adsorb methylphenols to a much smaller extent. This has been accounted for due to the carbonaceous adsorbent having a larger porosity and consequently higher surface area. The adsorption of phenols on this carbonaceous adsorbent as a function of contact time, concentration, and temperature has been studied by the batch method. The adsorption has been found to be endothermic and data conform to the Langmuir equation. The analysis of data indicates that adsorption is a first-order process and pore diffusion-controlled. The efficiency of the carbonaceous adsorbent was assessed by comparing the results with those on a standard activated charcoal sample. It was found that the carbonaceous adsorbent is about 45% as efficient as standard activated charcoal and can therefore be employed for the removal of methylphenols from wastewaters.

Identification of a crystalline cyanide-containing compound in blast furnace sludge deposits.

During blast furnace operation, a cyanide-containing muddy waste referred to as blast furnace sludge is generated in large amounts. In Germany it was and is still common practice to pump this sludge into surface deposits. Depending on species, cyanide has very different toxicity. To this day there is no information about the type of cyanide occurring in blast furnace sludge deposits. In order to identify the type of cyanide we investigated by means of wet chemical and powder X-ray diffraction analyses 37 samples of three blast furnace deposits. Wet chemical results indicate that both the extremely toxic free cyanide (HCN and CN ) and toxic weak metal-cyanide complexes, for example [Zn(CN)4]2-, are not present in the sludge. By powder X-ray diffraction we identified the crystalline cyanide-containing compound potassium zinc hexacyanoferrate(II) nonahydrate, K2Zn3[Fe(CN)6]2 x 9H2O, as the cyanide-bearing compound. Our study is the first that identifies potassium zinc hexacyanoferrate(II) nonahydrate in the environment. As the iron-cyanide complex [Fe(CN)6] is not acutely toxic, any direct hazard comes from cyanide occurring in the investigated wastes. Under the predominant pH milieu of the sludge (pH about 8) the solubility of potassium zinc hexacyanoferrate(II) nonahydrate is low, thus minimizing the mobility of cyanide.

Method comparison for the determination of total cyanide in deposited blast furnace sludge

Blast furnace sludge is a cyanide-containing waste created during pig iron production. In this study the determination of total cyanide in 32 samples of a disused blast furnace sludge deposit was investigated using two methods. One method is based on a weight-in of solid material followed by an acid digestive distillation. If using a distillation time of 1 h, which is laid down in Germany as the standard method, total cyanide is underestimated. If the distillation time is prolonged to 2 h, the cyanide determination is quantitative. Results of these modifications of the German standard method were statistically equal to those obtained by an alkaline extraction using 1 M sodium hydroxide repeated three-fold, and followed by an acid digestive distillation of the extracts ( y=8.4+0.991 x; r=0.996; n=32). On an average, in the first extract 85%, in the second extract 12%, and in the third extract 3% of total cyanide was dissolved. Determination of total cyanide in deposited blast furnace sludge can be performed by an acid digestive digestion of solid material for 2 h as well as by a repeated extraction by means of 1 M sodium hydroxide.

Evaluation of the use of a sequential extraction procedure for the characterization and treatment of metal containing solid waste

Metal containing wastes like MSWI fly ashes and blast furnace sludge form a major environmental problem as they are polluted with heavy metals. The ash has to be landfilled or can be used as a construction material, but a pretreatment is in general necessary. Washing of the ashes with water in order to dissolve soluble salts or extracting the heavy metals with chemicals are possibilities. Blast furnace sludge contains large quantities of iron and carbon and could be recycled in the blast furnace, if the zinc content were not that high. Using a hydrometallurgical process the zinc can be removed from the sludge particles. In order to evaluate such treatment methods knowledge of the leaching behaviour of the studied material is very important. One of the factors influencing the leaching behaviour is the composition and mineralogy of the solids. A sequential extraction procedure, whereby the material is sequentially leached with different leaching solutions, can be used as an aid to characterize the material and to determine which chemical conditions are needed to obtain a sufficient extraction efficiency. To verify the accuracy of the sequential extraction procedure, a method is tested on MSWI fly ash and evaluated by comparing the results with those of leaching experiments whereby the final pH of the leaching solutions is varied over a wide range. Based upon this evaluation some suggestions for the use of the sequential extraction procedure are made and an adapted procedure is suggested, and applied to a blast furnace sludge.

Zinc and Lead Removal from Blast Furnace Sludge with a Hydrometallurgical Process

During the production of pig iron in a blast furnace, a Zn- and Pb-containing sludge is generated in the air pollution control system. This toxic waste can be landfilled after dewatering and pretreatment, which is very costly. The sludge particles contain large amounts of Fe and C that could be recycled in the furnace. However, the Zn content of the sludge is high, and the Zn input to the blast furnace must be limited, so Zn has to be removed. This paper describes a hydrometallurgical process whereby the sludge is leached under both acid (HCl) and oxidizing conditions. After the separation of the solids, which mainly contain C and Fe, from the leaching solution, the latter is passed through an anion exchanger to remove Zn and Pb and is recirculated to the reactor. Investigation of the leaching behavior showed that a pH below 1.5 and a redox potential above 650 mV are required to obtain high leaching efficiencies for Zn and Pb. Sequential extraction showed that the largest part of Zn and Pb is extracted in...

Utilization of Industrial Wastes in Low-Volume Roads

In recent years, applications of marginal materials, also called nontraditional (either natural or waste products), have been considered in road construction with great interest in many industrialized and developing countries. The use of nontraditional materials in road making is based on technical, economic, and ecological criteria. The lack of traditional road materials and the protection of the environment make it imperative to investigate marginal materials carefully. India has a large network of steel plants located in different parts of the country and many more are planned for the near future. Several million metric tons of iron and steel are produced in these plants. However, along with production of iron and steel, huge quantities of solid wastes like blast furnace slag and steel slag as well as other wastes such as flue dust, blast furnace sludge, and refractories are also being produced in these plants. The iron ores in India, although rich in iron content, are high in alumina content also and as such the volume of slag generated is very high. Normally production of 1 metric ton (1 Mg) of steel generates 1 Mg of solid waste. Although the steel industry slags have their own unique properties and are exploitable for road works, they have never been put to use on Indian roads because of a lack of scientific studies conducted on these materials, nonavailability of proper design and construction standards on them, and the absence of data about the long-term behavior of these materials. In the absence other outlets, these solid wastes have occupied several acres of land around plants throughout the country. Keeping in mind the need for bulk use of these solid wastes in India, it was thought expedient to test these materials and to develop specifications to enhance the use of slags in road making, in which higher economic returns may be possible. Exhaustive and detailed laboratory investigations have been carried out at the Central Road Research Institute, New Delhi, India, to develop suitable specifications for construction of low-volume roads. Based on laboratory investigation results, specifications were developed for construction of low-volume roads in different parts of the country. While specifications were being formulated, attempts were made to maximize use of solid wastes in different layers of the road pavement. Postconstruction pavement performance studies have clearly indicated that these waste materials can be used for construction of low-volume roads with twofold benefits: ( a) it will help clear valuable land of huge dumps of slags, and ( b) it will also help preserve the natural reserves of aggregates, thus protecting the environment.

Adsorción de metales pesados sobre lodos de horno alto

Most of industrial liquid effluents have high contents of heavy metals. The recovery of these metals is environmental and economically interesting. In this work we study the use of sludge, a by-product of the steel industry, as an adsorbent for the removal of heavy metals from liquid effluents. The adsorption of Pb 2+ , Zn 2+ , Cd 2+ , Cu 2+ and Cr 3+ on the sludge was investigated by determination of adsorption isotherms. The effect of time, equilibrium temperature and concentration of metal solution on sludge adsorption efficiency was evaluated. The adsorption process was analysed using the theories of Freundlich and Langmuir and the thermodynamic values Δ G , Δ H and Δ S corresponding to each adsorption process were calculated. Blast furnace sludge was found to be an effective sorbent for Pb, Zn, Cd, Cu and Cr-ions within the range of ion concentrations employed.

Sorption of heavy metals on blast furnace sludge

An investigation into the use of sludge, a by-product of the steel industry, as an adsorbent for the removal of heavy metals from liquid effluents was carried out. Gases produced in the blast furnace were washed and led towards a Dorr thickener where the sludge was obtained as a suspension. The sorption of Pb 2+, Zn 2+, Cd 2+, Cu 2+ and Cr 3+ on the sludge was investigated by determination of adsorption isotherms. The effects of time, equilibrium temperature and concentration of metal solution on sludge adsorption efficiency was evaluated. The adsorption process was analyzed using the theories of Freundlich and Langmuir and the thermodynamic values of Δ G, Δ H and Δ S corresponding to each adsorption process were calculated. Blast furnace sludge was found to be an effective sorbent for Pb, Zn, Cd, Cu and Cr–ions within the range of ion concentrations employed.

The adsorption of copper (II) ions from aqueous solution on blast furnace sludge

The financial assistance provided by the Comision Interministerial de Ciencia y Tecnologia (Programa Nacional de Materiales, Proyecto MAT93-0096) is gratefully acknowledged.

Adsorption of Pb2+ on blast furnace sludge

AbstractAn evaluation of the applicability of blast furnace sludge, generated during the purification of blast furnace gases, as an adsorbent to remove heavy metals from industrial effluents is presented. The influence of residence time and temperature on the adsorption efficiency of the sludge is studied for the particular case of Pb2+. The adsorption data, which fit the Langmuir equation well, show that the blast furnace sludge has a high adsorption capability, up to 80 mg Pb per g dried sludge at saturation. The order of magnitude of the adsorption enthalpy, calculated from the apparent equilibrium constant, indicates that the adsorption of Pb2+ on the sludge is of a physical nature. XPS and EDAX analysis suggest that the physical adsorption process partially occurs through ionic exchange between Pb2+ and other ions such as Ca2+. Techniques exist for the recovery of metallic iron and either metallic lead or lead oxide from the sludge. The rendering of sludge into pellets, followed by their controlled heating, allows not only the extraction of these metals, but also makes use of the coke within the sludge. These techniques are clearly interesting alternatives to the dumping of this toxic and hazardous waste.

The utilization of converter and blast-furnace sludges

The utilization of converter and blast-furnace sludges

Environmental Impact of Cadmium: A Review by the Panel on Hazardous Trace Substances

Environmental Impact of Cadmium: A Review by the Panel on Hazardous Trace Substances

Environmental impact of cadmium: a review by the Panel on Hazardous Trace Substances.

This report is the result of a review by a Panel on Hazardous Trace Substances, as part of a report to an ad hoc Committee on Environmental Health Research whose chairman was Dr. David Rall, Director of the National Institute of Environmental Health Sciences, NIH.