Minerals free fulltext multianalytical characterization of slags. Recovery of chromium from ferrochrome slag is 64% by treatment of slag with lime at 973k in solid phase. The benefits of using ferrochrome slag as waste aggregate. In ferrochrome smelting operations, the manganese should find its way into the slag rather than the metal. Thermo chemical characteristics of the materials were taken from reference books, the missing data. Environmental impact of ferrochrome slag in road construction. Ninita enterprises, rasulgarh, bhubaneswar in odisha.
The complete book on ferroalloys ferro manganese, ferro molybdenum, ferro niobium, ferro boron, ferro titanium, ferro tungsten, ferro silicon, ferro nickel, ferro chrome an alloy is a mixture or solid solution composed of metals. Particle size and chemical composition of the raw materials. Important factors are temperature and composition of the slag, viscosity and electrical conductivity. Jigging recovery of chromium slag process of ferrochrome. Although the bulk of slag ends up on landfills, slag is used in the construction, agriculture and marine industry among others. In case of substitution of ferrochrome silicon used as a reductant in lowcarbon ferrochrome production for less expensive ferrosilicoaluminum, made of industrial wastes, it is possible to have a slag with a nearhelenite phase composition.
Ferrochromeferrochrome manufacturers, suppliers and ferrochrome slag is a byproduct from the production of sell offer spot fecr 60% safricaindia hc ferrochrome of nitrogen b. Aim of this work was to prepare conventional castable and low cement castables by utilizing this waste ferrochrome slag, calcined bauxite and microsilica. Ferrochrome slag, a major solid waste in ferrochrome industries faces the disposal problem because of residual chromium content in it. A wide variety of ferro chrome slag options are available to you, there are 42 suppliers who sells ferro. For ferrochrome, slag production varies according to the type of fecr produced. Ferrochrome slag shows excellent properties to replace. The results of the activities of the chromium oxides are presented in figure 3.
The resulting ternary slag contained in mass percent about 3040% mgo, 3040% al2o3 and 2030% sio2. The composition and leaching tests of the ferrochrome slag show that the chromium content is high, %, although leaching under normal. The chemical and mineral composition and refractoriness of the main varieties of slag are identified. The primary components of iron and steel slag are limestone cao and silica sio 2. Information is summarized and results are provided for comprehensive study of ferrochrome aluminothermal slags carried out over several decades by both home specialists and the authors of the article. In the intense heat the carbon reduces the metal oxides to the molten alloy, which. Utilization of ferrochrome wastes such as ferrochrome ash. The results obtained in the present study are compared with synthetic as well as slag samples as per the specifications of manufacturers. The chemical and mineralogical composition of steel slag produced in two arcelormittal steel plants located in the north of spain, as well as the study of the influence of simulated environmental conditions on the properties of the slag stored in disposal areas, was carried out by elemental chemical analysis, xrf, xray diffraction, thermal analysis, and scanning electron microscopy with eds. Flexural strength of the sample with 10% ferrochrome slag specimen is more than control sample 0% ferrochrome slag.
Economic and environmentally beneficial treatment of slags in. Ferrochrome slag is mostly solid dry slag, hardness is very big, is gray black, according to the different of smelting process, ferrochrome smelting slag containes different. Chemical properties the chemical composition of ferrochrome slag aggregate is shown in table 1. As highcarbon ball bearing steel, alloying agent of tool steel and highspeedsteel to improve steels hardenability, increase its abradability and hardness. During the blowing, a small amount of lime and fluorite are added to the molten pool to form a slag, and a siliconchromium alloy or ferrosilicon is added before the iron is discharged to recover the chromium in the slag. Development of high strength concrete using ferrochrome slag.
Ferrochromium, alloy of chromium with 30 to 50 percent iron, used to incorporate chromium into steel. In this paper the experimental studies of ferrochromeslag and stone dust will be discussed. Page 2 chemical and mineralogic composition chemical analyses of blastfurnace slags usually show that the four major oxides lime, magnesia, silica and alumina make up about 95% of the total. In europe, steelmaking slags are used predominantly as aggregates in road construction 46%, with smaller quantities used in metallurgy or as fertilizer. It can be seen that the solubility of crox in the slag is about 60 mol%, if the slag is. This new study tracks and critically analyses how this market will develop across the next ten years, with forecast growth at 1. This was done to evaluate the possibility ofusing xrf as an alternative technique to improve the turnaround times at the plant laboratory. The slag composition is an important part in ferrochrome smelting technology. Environmental and technical assessment of ferrochrome slag as. Common phases in the slag are glass, spinels al 2 o 3 mgo and forsterite mgosio 2, and small amount of cao. Slag is usually a byproduct of metal production, although there are processes such as ilmenite smelting, for example where the slag is the principal product. The ferrochrome slag aggregate properties are determined and tabulated in table 4. Data from these analyses have most often been used to trace the partitioning of the manganese through the smelting process and for material balance calculations.
Oct 24, 2015 an innovative way of utilizing ground granulated blast furnace slag is to activate it using alkaline materials. Reuse of waste ferrochrome slag in the production of. Ferrochrome smelting slag gravity separation technology. It is produced in an electric furnace using chromium ore, iron or iron ore, and carbon, usually anthracite coal. Chromium present in the slag reacts with lime to form mixed chromates. South africa, the leading producer of ferrochrome does not take ad. Valuable utilization of ferrochrome slag for wastewater treatment priyanka saha and supriya sarkar environment research group, research and development, tata steel ltd, jamshedpur 831 007, india during ferrochrome production, slag is discarded as a waste material in huge quantities. Other components of blast furnace slag include alumina alsub2 o 3 and magnesium oxide mgo, as well as a small amount of sulfur s, while steelmaking slag contains iron oxide feo and magnesium oxide mgo.
The main components of the slag are sio2, mgo and al2o3. The latter slag type is presented in figure 5 and figure 6. Heterogeneity in ferrochrome slag has been found to depend significantly on the amount of alloy entrainment in slag, and therefore the slag viscosity, tapping temperature and chemical composition. The future of nonferrous slag to 2029 in 2019 production volumes of nonferrous slag will be over 116. Experience is reflected for application and prospective areas are considered for utilization of ferrochrome slag. Ultimately, this allowed producers to assess the influence of various raw material inputs on the power consumption, slag properties, and alloy grade. Reuse of waste ferrochrome slag in the production of mortar. Because of the high carbon ferrochrome as smelting slag, chromium ores contain only 30%50% chromium oxide, so in smelting process other ingredients of minerals in the form of slag together with molten iron are discharged out of furnace body to form the chrome slag. Some slags are basically unstable at high temperatures since two or more components in the slag will react and the composition will change continuously eg esr slags where fluorides and oxides react eg. Composition of metal and slag phases in dependence on charge of. Journal of chemical and pharmaceutical research, 20, 55. Duplex process for production of low carbon ferrochrome. Chromite is divided into high carbon ferrochrome including charging fecr with different carbon content c. Any further queries please feel free to contact me at.
With the exception of potassium k, which had a potential leaching capacity availability test of around 16%, the leaching of chromium, nickel, zinc and other elements was just a few. Ferro tungsten, ferro silicon, ferro nickel, ferro chrome, ferroalloy. Liquid carbon ferrochrome is used as a raw material. Research articles valuable utilization of ferrochrome slag. Production, characteristics, and use of ferrochromium slags. Even though the slag has the desired engineering and mechanical properties, its use has been restricted because of leaching of chromium often exceeding the regulatory norms under adverse environmental conditions. Slag samples from a ferrochrome smelter were analyzed using an xrf powder pellet analytical technique in contrast to the rep technique used at the plant laboratory, to determine their composition.
The slag composition is tested every day by sampling and analysis. The typical ferrochrome slag composition is 30 % sio 2, 26 % al 2o3, 23 % mgo and 2 % cao. Aug 08, 2018 this study focuses on the reuse of waste ferrochrome fecr slag as a partial replacement for sand in the production of cement mortar with improved thermal and mechanical properties. The slag also includes cr and fe oxides and calcium oxide. Ferrochrome is an inorganic material and it is not classifiable as a pbtvpvb substance.
Implementation of industrial waste ferrochrome slag in conventional. Using modern process control and good quality charge materials the optimal slag composition can be attained. This study focuses on the reuse of waste ferrochrome fecr slag as a partial replacement for sand in the production of cement mortar with improved thermal and mechanical properties. Extensive tests have been carried out on the physical properties of the ferrochrome slag from vargon alloys and it was found to be highly suitable as road. Thermo chemical characteristics of the materials were taken from reference books, the. The analysis of insoluble residues and comparison with a standard reference. Commonly used silicon chromium alloys, ferrochrome nitride etc. Zimbabwes major producers of ferrochrome cut back on production approx. Ferrochrome smelting slag is also known as ferrochrome slag and chromium slag, etc. The results of an integrated study of highalumina slag generated in the production of ferrotitanium, ferrochrome, and metallic chromium by the aluminothermic method at the kluchi ferroalloyworks are described. Chemical composition of ferrochromium slag can be altered suitably for application in high. The slag is crushed and sold in different fractions between 0100 mm. Most of the worlds ferrochrome is produced in south africa, kazakhstan and india, which have large domestic chromite resources. Properties and uses of iron and steel slag mf 1826 national slag association.
The concentrations of the other elements of interest mo, v, nb are too low for mineralogical identification. At present domestic discharged way is divided into dry slag method and water slag. Siple united states department of the interior manuel lujan, jr. Utilization of ferrochrome wastes such as ferrochrome ash and ferrochrome slag in concrete manufacturing.
Ferrochrome, or ferrochromium fecr is a type of ferroalloy, that is, an alloy between chromium and iron, generally containing 50% to 70% chromium by weight. Manganese in mineral chromite, ferrochrome slags, and ferrochrome acid digestion of ferrochrome metal analysts assigned to make a new determination on a sample often must deduce the significance of steps in the usually sketchy procedure descriptions of inhouse methods and methods in journal or reference publications. The ferrochromium slag is an important byproduct of ferrochromium industries. Rate of leaching in both acids was found to be 1st order kinetics. An innovative way of utilizing ground granulated blast furnace slag is to activate it using alkaline materials. Fluxing to produce the required slag composition was carried out using either silica or a combination of silica and lime in the form of burnt lime or limestone. Figure 1 indicates the theoretical minimum amount of energy and reductants required for ferrochrome fecr production utilizing either ac or dc furnaces for various raw. Ferrochrome slag is treated with lime to conduct slaglime solidsolid reaction. In this paper industrial waste was collected from gts industries and used in the subsequent experimentation. Production, characteristics, and use of ferrochromium. The benefits of using ferrochrome slag as waste aggregate in south africa e moodie 23332867 dissertation submitted in fulfilment of the requirements for the degree of magister scientiae in geography and environmental management at the potchefstroom campus of the northwest university supervisor. The composition and leaching tests of the ferrochrome slag show that the chromium content is high, %, although leaching under normal conditions is very low. The slag has a composition of about 2528% cr203 and 40% cao.
Recycling and efficient utilization of the large volumes of slag generated by ferrochrome production process is a huge challenge for ferrochrome producers. Previous researches have shown that the content of alumina in such slag can be as high as 29%. Fecr slag mineralogy to study chromium bearing mineral phases and other mineral phases. It is now well recognised that the physical, chemical and thermal properties of aggregates substantially influence the properties and performance of concrete. Development of high strength concrete using ferrochrome. Leaching of chromium from ferrochrome slag kothavalasa using hydrochloric and nitric acid media was attempted. Cao 10 mol%, sio2 40 mol%, mgo 35 mol% and al2o3 15 mol%. The main objective of this study was to investigate the effects of activator type and curing conditions on the compressive strength and electrical resistivity of alkaliactivated ground granulated blast furnace slag mortars. Minerals free fulltext multianalytical characterization. Ferrochrome, or ferrochromium fecr is a type of ferroalloy, that is, an alloy between chromium and iron, generally containing 50% to 70% chromium by weight ferrochrome is produced by electric arc carbothermic reduction of chromite. To obtain mortars consisting of waste materials was also an. Microscopic studies to evaluate the chemical composition and structural aspects of different phases present in slag matrix.
Utilization of ferrochrome wastes such as ferrochrome ash and. Implementation of industrial waste ferrochrome slag in. In untreated conditions the bulk density of the slag is around 1. The replacement of ferrochrome slag partially to the cement in concrete will not only conserve the cement but also reduces the. Ferroalloys thus show different properties as mixture of different metals. Valorization of ferrochrome slag stellenbosch university. Methods for the analysis of mineral chromites and ferrochrome. Effects of activator properties and ferrochrome slag. Water absorption of ferrochrome slag aggregates as per is 2386iii, 1997 is found to be 1. Environmental and technical assessment of ferrochrome slag.
The chromium from liquid extract is separated with fly ash based zeolite which has 3000 mmolgram and it can be regenerated to recover chromium. Composition of metal and slag phases in dependence on charge of reducing agents and flux limestone has been received with thermodynamic analysis. Mass and composition of slag mass and composition of metal mass and composition of off gas with or without co combustion electric energy consumption recovery rate of cr, fe. Ferrochrome aluminothermal slags as a multifunctional. The material properties of these slags show excellent properties for reuse in the construction industry. Slag arising from smelting in the production of ferrochrome alloys, stainless steel and platinum group metals pgm is known to contain residual chromium in various phases within the slag matrix. Full text of methods for the analysis of mineral chromites. Recovery of chromium from ferrochrome slag open access journals. The ferrochrome slag aggregate is confirming to is. In this chapter, the properties of the slag produced during ferrochrome. The outcome from this was the development of a roadmap, which proposes how the utilization of ferrochrome slag might be increased. The chrome content in the slag is about 8 % and the iron content 4 % respectively. In the ferrochrome slag, cr is also contained within metallic ferrochrome particles. One can therefore conclude that the sampling constant and therefore sample mass is dependent onfurnace operating conditions.
Information circular 9240 methods for the analysis of mineral chromites and ferrochrome slag by d. Ferrochrome is not known to contain any 0,1 % or any ferrochrome is not listed as hazardous waste in the european list of waste commission. Slag production is relatively higher for lowcarbon ferrochrome lc fecr 2. Manganese in mineral chromite, ferrochrome slags, and ferrochrome. The results of these campaigns primarily demonstrated the robustness and flexibility of the dc arc furnace.
Ferrochrome slag ore beneficiation process introduction and. Jigging recovery of chromium slag process of ferrochrome jigging process. Pdf utilization of ferrochrome wastes such as ferrochrome. Similarly, ferroalloys are the mixture of iron with. Changes in the composition of slag and metal associates at the flow rate ferrosilicochrome and aluminum in the ratio 11 al 294,6 the usage of the complex reducing agents results in the process when a part of chrome fixes in the slag in the form of silicate cr2si04 and the calculated level of chrome reduction, in the. The complete book on ferroalloys ferro manganese, ferro. Sand was replaced by fecr slag in different percentages ranging from 0 up to 20% by weight. The production of ferrochrome alloy from chromium bearing. It has been observed that ferrochrome slag waste is a suitable material for highway pavement work.
829 1604 975 348 481 1185 557 170 141 1378 1401 37 1123 1276 1500 123 1494 1272 673 937 1609 820 135 20 443 1067 865 790 769 336 1055 1206