CHROMIUM ALLOYS PRODUCTION AND OPERATION As already stated, due to loss of Cr in slag in the present production process of HC FeCr in submerged arc electric furnace there is a limitation of recovering only 84 - 88% of chromium in
Dec 10, 2013· Total chromium has been identified in 939 soil and 472 sediment samples collected from 1,036 National Priority Lists (NPL) hazardous waste sites [HazDat 2000] Chromium waste slag containing potentially hazardous levels of Cr(VI) compounds was used as fill material at more than 160 residential, industrial, and recreational sit
Chromium: Outokumpu considers new slag furnace in Tornio Posted 8th October 2019 in Industry news By Nils Backeberg Outokumpu is assessing options to build a new slag furnace in Tornio, Finland, on which a decision will be made in 2020 The company has initiated an Environmental Impact Assessment (EIA) procedure as a basis for decision making
It was determined that above a 20 CaO/SiO 2 ratio, chromium exists in slag as calcium chromite, which can be vulnerable to leaching by acid precipitation, especially if it is oxidized to calcium chromate when exposed to the environment over an extended period
Jun 04, 2001· The present invention relates to a method for reduction of chromium content in slag during melting of stainless steel in electric arc furnaces where steel scrap and additive alloys are melted in an electric steel furnace, whereafter molten steel and slag are tapped into a ladle, removal of the slag from the steel in the ladle, transferring of the molten steel from the ladle to a converter .
The drivers were illegally dumping up to 5000 tonnes of chromium slag in nearby villag Chromium salts are widely used in metallurgy, tanning and paint and dye making, but their manufacture results in large amounts of slag which, if not processed, can form carcinogenic hexavalent chromium
The problem of chromium slag pollution is a great challenge for China It is now an urgent task for China to take effective measures to eliminate chromium slag pollution This article examines the case of the treatment of chromium slag in Shandong Province and explores how chromium slag pollution can be eliminated in Shandong Province
Hexavalent chromium or Cr(VI) is a toxic form of chromium that can cause severe health effects to workers, including lung cancer Chromium compounds are added , steel shot or slag abrasives are common methods for removing old paint from steel structur Slag abrasives can cause exposure to ,
The invention relates to a method for removal of chromium and/or Nickel from a liquid slag or mixtures of slag and particulate matter, in which the molten slag is served in a liquid metal bath, in particular Fe-tub, and restored by the introduction of carbon or media carbon
Aug 29, 2014· where η 1 is the release percentage of Cr(VI) from the chromium-slag, m 1 is the accumulative content of Cr(VI) in the leakage, m 0 is the amount of chromium-slag and η ,
chromium were measured in distilled water followed by rain water and Britton-Robinson buffer o evaluate the T leachability of the concrete samples with various portions of slag addition, the Cr (VI) leached-out masses were calculated per 1 kg of binder The comparison of the dissolved concentrations of chromium in ppm (mg/kg) hexavalent is
A batch of column experiments was carried out to investigate the change of Cr(VI) concentration leached out from chromium-containing slag with HCl as leaching agent, and to study influences of pH .
Here we demonstrate a calcifying ureolytic bacterium Bacillus sp CS8 for the bioremediation of chromate (Cr(VI)) from chromium slag based on microbially induced calcite precipitation (MICP) A consolidated structure like bricks was prepared from chromium slags using bacterial cells, and five stage Cr(VI) sequential extraction was carried out to know their distribution pattern
FeCr slag is found to be suitable as construction material due to its excellent technical and material properties but its use has been limited by the environmental concern of release of chromium from slag Blended with fly ash there is a decrease in chromium leaching from the slag matrix
To investigate the feasibility of detoxifying chromium slag by sewage sludge, synthetic chromium slag containing 3% of Cr(VI) was mixed with sewage sludge followed by thermal treatment in nitrogen gas for stabilizing chromium The effects of slag to sludge ratio (05, 1 and 2) and temperature (200, 300, 500, 700 and 900 degrees C) on treatment .
PROBLEM TO BE SOLVED: To provide a method for recovering chromium in slag by which chromium oxide contained in the slag developed when molten stainless steel is subjected to decarburization refining, is efficiently reduced and recovered in the molten stainless steel and the lowering of the chromium contained in the slag is performed and the recycling of the slag can be ,
US3106447A US15065261A US3106447A US 3106447 A US3106447 A US 3106447A US 15065261 A US15065261 A US 15065261A US 3106447 A US3106447 A US 3106447A Authority US United States Prior art keywords reaction mixture mixture metallic carbon spinel Prior art date 1961-11-07 Legal status (The legal status is an assumption and is not a legal conclusion
The chromium elution behavior of stainless steel (SS) slag depends highly on the chromium distribution, and the molten modification process proved to effectively improve the chromium enrichment in stable phas However, the phase transformation and variation of chromium stability during the subsequent cooling process is still poorly understood
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 construction material The composition and leaching tests of the ferrochrome slag show that the chromium content is high, 1-3%, although leaching under normal conditions is very low
The basicity of slag (the mass ratio of basic components to acidic components) increases with lime fusing, which causes a variation of elemental distributions in various phases [11–13] However, there are discrepancies in the literature regarding the inﬂuence of the basicity of slag on the chromium migration behavior in the SSS
CHROMIUM L &E EPA-450/4-84-007G July 1984 Locating and Estimating Air Emissions From Sources of Chromium US ENVIRONMENTAL PROTECTION AGENCY Office of Air and Radiation Office of Air Quality Planning and Standards Research Triangle Park, North Carolina, NC 27711
Both the activities of CrO and Cr 2 O 3 in slag were found to increase approximately linearly with the increase of the total Cr content in slag While the oxygen partial pressure had minor effect on the activity of Cr 2 O 3 in the slag, it had significant effect on the activity of CrO , The activity coefficients of chromium in Cu-Cr melts .
A method for recovering metallic chromium from slags which contain chromium oxide from converter processes, such as AOD, MRP, AOD-L, MRP-L, CLU, ASM, Conarc stainless steel or vacuum processes, such as VOD, SS-VOD, RH, RH with lanze, includes drawing off the slag which is produced at the end of a blowing or treatment operation in a converter or a vacuum installation in unreduced form
The invention discloses a method for extracting vanadium and chromium from converter vanadium chromium slag The method comprises the following steps: 1) adding Na2CO3 into the vanadium chromium slag, mixing uniformly and carrying out oxidizing roast on the mixture, wherein the addition of Na2CO3 is controlled according to a molar ratio of V2O3/Na2CO3 in the vanadium chromium slag ,
• Coal slag and garnet sand may cause lung damage similar to silica sand (based on preliminary animal testing) • Copper slag, nickel slag, and glass (crushed or beads) also have the potential to cause lung damage • Steel grit and shot have less potential to cause lung damage • Slags can contain trace amounts of toxic metals
Chromium is an essential element in steelmaking industry Steel slag inevitably contains some chromium and there is a risk of Cr emission from slag to the environment, however, in which form the emission of the element occurs and whether it is a hexavalent Cr is a concern To
The immobilization of hexavalent chromium in stainless steel slag using blast furnace slag as the immobilizing agent and by performing a hydrothermal treatment was investigated The results showed that there was no immobilization in the absence of the blast furnace slag On the other hand, the hexavalent chromium in stainless steel slag could be immobilized through the hydrothermal reaction .
A new synergistic treatment of stainless steel slag and low zinc content electric arc furnace (EAF) dusts is proposed to immobilize harmful chromium in stainless steel slag
Mar 06, 2020· Slag is a byproduct of metal smelting, and hundreds of tons of it are produced every year all over the world in the process of refining metals and making alloysLike other industrial byproducts, slag actually has many uses, and rarely goes to waste It appears in concrete, aggregate road materials, as ballast, and is sometimes used as a component of phosphate fertilizer
Mar 28, 2019· The transport and fate of hexavalent chromium Cr(VI) in slag–soil system, which remain poorly understood, are of great importance for environmental risk assessment and pollution control of Cr(VI) in soil and groundwater Based on the migration behavior of Cr(VI) in the chromium-containing slag under the effects of rainfall, the transport and fate of Cr(VI) in soil were investigated Batch .