3 edition of Na₂CrO₄ from domestic chromite concentrates by an alkali-fusion method found in the catalog.
Na₂CrO₄ from domestic chromite concentrates by an alkali-fusion method
|Other titles||Alkali-fusion method|
|Statement||by Gary L. Hundley ... [et al.]|
|Series||Bureau of Mines report of investigations -- 9167, Report of investigations (United States. Bureau of Mines) -- 9167|
|Contributions||Hundley, Gary L|
|The Physical Object|
|Number of Pages||12|
"The Bureau of Mines has upgraded high-iron domestic chromite concentrates by a carbonyl process. The upgraded chromite concentrates show as much as 10 wt pct higher cr2o3 content and up to a threefold increase in the cr:fe ratio, compared with the starting concentrates. The Nutritional Relationships of Chromium David L. Watts, Ph.D., F.A.C.E.P.1 In a physiological role for chromium was determined. It is known that chromium is a constituent of the glucose tolerance factor (GTF) and is synergistic with insulin in promoting cellular glucose uptake. ChromiumFile Size: 79KB.
Chromite is the most important chromium ore mineral. It forms a complete solid solution series with many other members of the group, eg. in the Chromite-Hercynite Series, Chromite-Spinel Series, Chromite-Magnetite Series and the Chromite-Magnesiochromite is the iron analogue of Zincochromite, Cochromite, Manganochromite and Magnesiochromite and the Cr analogue of Hercynite. What is Chromite? Chromite is an oxide mineral composed of chromium, iron, and oxygen (FeCr 2 O 4).It is dark gray to black in color with a metallic to submetallic luster and a high specific gravity. It occurs in basic and ultrabasic igneous rocks and in the metamorphic and sedimentary rocks that are produced when chromite-bearing rocks are altered by heat or weathering.
Overview. Chromium (Cr) is the seventh most abundant element, but minerals containing chromium are not wide spread, with most of the high Cr ores deposits being found in te is the most common ore containing Chromium, with an empirical formula of FeCr 2 O Cr and Fe are present in Chromite in the +3 and +2 oxidation states respectively, which is why it is best written and. For Further Information. Behavior of Metals in Soils McLean, J.E. and B.E. Bledsoe. EPA S, 25 pp, This paper covers the fundamental processes that control the mobility of metals (lead, chromium, arsenic, cadmium, nickel, zinc, copper, mercury, silver, and selenium) in soil and describes laboratory methods used to evaluate the behavior of metals in soil.
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Na₂CrO₄ from domestic chromite concentrates by an alkali-fusion method (OCoLC) Material Type: Government publication, National government publication: Document Type: Book: All Authors / Contributors: Gary L Hundley; United States. Bureau of Mines. These domestic chromites contain silicon and aluminum impurities at levels that are too high to permit processing by present industrial processes.
The Bureau procedure consists of reacting chromite with molten naoh under oxidizing conditions to form sodium chromate (na2cro4).Cited by: 1. "The Bureau of Mines has devised a procedure to recover chromium chemicals from concentrates derived from low-grade domestic chromites.
These domestic chromites contain silicon and aluminum impurities at levels that are too high to permit processing. Download PDF: Sorry, we are unable to provide the full text but you may find it at the following location(s): (external link) http.
Alkali-Fusion Method. The Bureau of Mines has devised a procedure to recover chromium chemicals from concentrates derived from low-grade domestic chromites.
These domestic chromites contain silicon and aluminum impurities at levels that are too high to. The possibility of producing chrome(VI) oxide from domestic chromite concentrates was investigated by carrying out laboratory-scale alkali fusion and water leaching experiments. The effects of temperature, the amount of NaOH added and the flow rate of air on chromium extraction efficiency in an alkali fusion step were by: The alkali-fusion method was carried out by reacting chromite concentrate with molten sodium hydroxide under oxidizing conditions to form sodium chromate.
The fusion product. After the liquid oxidation decomposition of chromite in molten salts, the reaction slurry is diluted to 50% sodium hydroxide solution.
Then the filtration is carried out to separate the alkali liquor and the mixtures of ferrite-enriched residue and Na 2 CrO 4 crystal. The filter cake is leached by water to dissolve Na 2 CrO 4, and then the residue is separated from Na 2 CrO 4 by: The effect of parameters such as fusion temperature (, and °C), fusion time (20, 40, 60 and 90 min) and the weight ratio of NaOH to Cr2O3 in the chromite on alkali fusion was investigated.
Method of production of chromite concentrate. The method of obtaining chromite concentrate is C poor chromium ores, includes grinding the ore, roasting, leaching acid circulating the filtrate, filtering the suspension, washing and drying the obtained chromite concentrate, characterized in that the calcining is carried out at a temperature of.
Catalog Record: Na₂CrO₄ from domestic chromite concentrates by an alkali-fusion method | HathiTrust Digital Library. General Chromite Information: Chemical Formula: Fe++Cr2O4: Composition: Molecular Weight = gm Chromium % Cr % Cr 2 O 3: Iron % Fe % FeO: Oxygen % O: % % = TOTAL OXIDE.
A novel process for leaching chromite ore has been proposed. Compared to the traditional alkaline roasting process, the new hydrometallurgical process lowers effectively the reaction temperature and enhances the leaching efficiency through pressure oxidative leaching with pure oxygen (O 2) in concentrated sodium hydroxide (NaOH) aqueous chromium (Cr) leaching efficiency Cited by: The Bureau procedure consists of reacting chromite with molten sodium hydroxide (naoh) under oxidizing conditions to form sodium chromate (na2cro4).
The reaction product is leached with methanol to remove the majority of the unreacted sodium hydroxide, then with water to remove the sodium chromate and the remainder of the sodium hydroxite. Extraction of chromium from domestic chromite by alkali fusion.
U.S. Bureau of Mines, Report of Investigations, RI Process for the production of sodium chromate from chromite ore. The Bureau of Mines has devised a procedure to recover chromium chemicals from low-grade domestic chromites, which contain silicon and aluminum impurity levels that are too high to permit processing by present industrial processes.
The Bureau procedure consists of reacting chromite with molten sodium hydroxide (naoh) under oxidizing conditions to form sodium chromate (na2cro4). Liquid-phase oxidation method is an alternative approach to treat chromite ores, and has been extensively studied for decades (Arslan and Orhan,Hundley et al.,Kashiwase et al.,Yildiz and Sengil, ).The essence of such a method is to oxidize the trivalent chromium in the chromium–iron spinel to water soluble chromate salts in alkali-hydroxide melts or by: The negative Δ r H 0 values of reactions, in Fig.
4 show that the oxidation decomposition of chromite ore is a high exothermic reaction with lowest values from K to K. Download: Download full-size image; Fig. Δ r G θ of reactions, in oxidation decomposition of chromite Cited by: 9.
Unfortunately, this book can't be printed from the OpenBook. If you need to print pages from this book, we recommend downloading it as a PDF. Visit to get more information about this book, to buy it in print, or to download it as a free PDF. Chromite ore sand/ concentrate- typical size at 5cubic mm and below- % Chrome lump size- 10cubic mm to cubic mm- 80% Min.
10cubic mm and below- 20% Max By bulk or bags/ sacks of 50kgs each and tied or 20ftr cont van with content in loose bulk or pack in 50kgs. Chromite concentrate, when combined with a reductant such as coal or coke and a high temperature furnace can produce ferrochrome.
Ferrochrome is a type of ferroalloy that is an alloy in between chromium and iron. This ferroalloy, as well as chromite concentrate can Category: Oxide minerals, Spinel group, Spinel .Chromite is an iron chromium oxide: FeCr 2 O4.
It is the principal ore of chromium, a brownish-black oxide of chromium and iron. It is an oxide mineral belonging to the spinel group.
Magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite.Other articles where Chlor-alkali process is discussed: chemical industry: Commercial preparation: The chlor-alkali industry—in which chlorine and caustic soda (sodium hydroxide) are produced simultaneously by electrolytic decomposition of salt (sodium chloride)—has become the principal source of chlorine during the 20th century.
As noted earlier, in the two important versions of the.