Chromite sand

Chromite is a chrome ore, with the theoretieal formula Fe0.Cr203, which contains other components such as magnesium and aluminium oxides. For its use in foundries, its silica content must be lower than 2 % in order to prevent sintering at low temperatures. Its characteristics are as follows  

Chromite sand is more refractory than silica. It is more thermally stable and has a greater chilling power. Chromite sand provides a better surface finish on large castings. It is therefore used for the production of large castings and in areas of the mould where chilling is required. 

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Leaching tests showed that the leaching of metals is generally low and that the leaching of chromiiun caused by the presence of chromite sand is negligible [169, Orkas, 2001],... 

Schachtner, J. and Muller-Spath, G. (1993). "Demonstrationsanlage zur thermischen Altsandregenerierung mit Komponententrennung flir Quarz- und Chromerzsand (Demonstration Plant for Thermical Regeneration of Used Sand with Components Separation of Silica and Chromite Sand - Final Report 9010)", Umweltbundesamt, UBA3 0 441-2/4,... 

Fig. 1. Global distribution of seabed mineral deposits, where x represents chromite + barite titanium, zirconium, hafnium, and thorium tin I gold, platinum, and silver 3 sand and gravel shell, calcium carbonate gems marine polymetaUic sulfides phosphorites Cl cobalt cmsts S sulfur and B...

Foundry resins, phenolic, 18 788—789 Foundry sand, chromite application, 6 493-494, 497 4A zeolite. See Zeolite 4A Four-component color matching system,... 

Krishnaswamy R. 1984. Study of availability and composition of metal bearing wastes (generated in titanium extraction and fabrication, aluminum smelters, chromite bearing refractory and foundry sands and mercury battery industries). Report to US Bureau of Mines, Washington, DC, by NH Parker, PE and Associates, La Crescenta, CA. NTIS No. PB84-207091. 

Similar relationships are found for other elements like Sc and Cr. In the sand-sized fractions, the REE distribution patterns show a more pronounced negative Eu anomaly and higher La/Lu ratio for the material from Unit N as compared to samples from Unit B. Interpretation of these observations is difficult because the heavy fractions contain as many as 10 different minerals. Pyroxene (mainly augite), amphiboles (mainly hornblende), iron oxides, chromite, ilmenite, rutile, and zircon were identified by using a polarizing microscope and energy-dispersive X-ray analysis. However, the... 

The catalyst used in this study was a copper chromite doped with barium (YPl). The other solids were prepared from that catalyst by impregnation with alkaline salts from Prolabo (LiNOj, KOH, CsNOs). After impregnation, the catalysts were dried in a sand-bath (120°C), and then calcinated at 350°C for 4 hours under a dry air stream. 

The type of foundry sand used is not critical and the usefiil foundry sands include all of the ones conventionally used in the metal casting industry. Thus, these sands can be zircon sands (zirconium silicates), silica sands, e.g., quartz, aluminum silicate, chromite, olivine, staurolite, and their mixtures. 

The general eharacteristics of zircon sand are similar to that of chromite, but zircon sand produces a better finish as a finer grade is used. These physical and thermal properties account for its use for moulding or core-making in difficult cases, in spite of its very high price. 

The mechanical primary regeneration -i- separation of chromite (from cores) and quartz sand (both chemically-bonded) + thermal/mechanical treatment of quartz sand was demonstrated on a pilot scale in Germany (1993). Separation of both sand t5q)es was needed because sintering and eutectics formation occurred in the mixed sand. The plant later closed down due to other economic reasons. 

Refractory-grade chromite is used for manufacturing magnesia-chrome bricks used in the extractive metallurgy of platinum group metals. Foundry sands made of chromite fines are used for making mould used for casting nonferrous metals. 

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