Biological, chemical and electromagnetic treatment of three types of feldspar raw materials

Bioleaching processes in combination with electromagnetic separation can substantially improve the quality of feldspar raw materials. Bacterial destruction of silicates is necessary for releasing intergranular spaces of silicate grains. These are often impregnated with iron minerals which can be sub...

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Bibliographic Details
Published in:Minerals engineering 2006-04, Vol.19 (4), p.348-354
Main Authors: Štyriaková, Iveta, Štyriak, Igor, Malachovský, Pavol, Lovás, Michal
Format: Article
Language:English
Subjects:
Bacteria
Bioleaching
Magnetic separation
Non-metallic ores
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Summary:Bioleaching processes in combination with electromagnetic separation can substantially improve the quality of feldspar raw materials. Bacterial destruction of silicates is necessary for releasing intergranular spaces of silicate grains. These are often impregnated with iron minerals which can be subsequently removed by electromagnetic separation. Bioleaching is also effective for the removal of surface layers of fine iron minerals. After the bioleaching, a new mineral, weddellite (calcium oxalate dihydrate), was identified in the fine grain fraction in samples. Weddellite is formed upon the destruction of Ca-plagioclase and its formation indicates that oxalic acid was one of the metabolites involved in the bioleaching process. Bioleaching resulted in a 35–41% decrease in Fe content of raw material from Strážov and the subsequent electromagnetic separation decreased the Fe content up to 69–74% of Fe. The second raw material was granite from Poproč and bioleaching removed 60% of Fe in spite of a high content of Fe 2O 3. The removal was increased up to 75% of Fe in combination with electromagnetic separation. Iron removal by biological leaching and electromagnetic separation ensures high quality and white color of raw material.
ISSN:0892-6875
1872-9444
DOI:10.1016/j.mineng.2005.10.010