Washing and classifying desliming
The SiO2 grade in quartz sand(silica sand) decreases by quartz
sand(silica sand) size becoming finer, so washing and desliming of
crude quartz sand(silica sand) is necessary before next step.
Scrubbing
Scrubbing is the way to remove film iron and impurity minerals on
the surface of quartz by mechanical force and crush these mineral
aggregate. The quartz sand gets further purification by
classification. There are two kinds of methods rob scrubbing and
mechanical scrubbing.
Flotation
The separation of mica and quartz is difficult, the effective
methods: anionic collector in acid condition and anionic - cationic
collector in alkaline condition. The purification of quartz sand
can reach 99% after scrubbing, desliming, magnetic separation and
flotation.
Acid Leaching
Dilute acid had a significant effect on removing iron and aluminum,
and concentrated acid for the removal of titanium and chromium, and
mixed acid for mineral impurity. Control various factors of acid
leaching should be based on quartz final grade requirements, and as
far as possible reduce the acid concentration, temperature and
dosage to achieve quartz purification.
♦ Case
A quartz sand(silica sand) dressing plant in Yunnan with the main
component was quartz sand(silica sand) accounting for 95-97%;
siliceous cement accounting for 8-23%, the impurity minerals were
hematite, limonite, etc. accounting for about 1-3%. The plant
adopted screen classification - dry magnetic separation - dosing
strong scrubbing-flotation process, the final indexes: SiO2 ≥
97.62%, Fe2O3 ≤ 0.24, Al2O3 ≤ 1.11%.The poor indexes seriously
affect the production and economic benefit. Therefore, the plant
commissioned the Xinhai to reform technology. By dressing tests,
Xinhai decided to adopt the screen classification - dry magnetic
separation - dosing strong scrubbing - acid leaching process.
After the technical reformation, the purified quartz sand(silica
sand) met the quality requirements of silicon powder, and it can be
used in ceramic, paint, metal casting industry after the superfine
grinding.
♦ Process Flow
