Production technology of quartz sand:
1. Wash with water and desliming by stages.
The grade of silica in quartz sand decreases with the increase of the fineness of quartz sand, but the grade of impurity minerals is the opposite, which is especially obvious in quartz sand containing a large number of clay minerals. Therefore, it is very necessary to wash and desliming the quartz sand before cleaning it.
scrub
Scrubbing is to remove thin-film iron and muddy impurity minerals on the surface of quartz sand by means of mechanical force between sand particles and abrasive stripping force, further crush non-monomer mineral aggregates, and then achieve the effect of further purifying quartz sand through classification operation. At present, there are two main methods: rod friction washing and mechanical scrubbing.
3. Flotation
It is difficult to separate mica from time. Good results can be obtained by using anionic collectors under acidic conditions or anionic collectors under alkaline conditions. Generally, after scrubbing, desliming, magnetic separation and flotation, the purity of quartz sand can reach over 99%, which basically meets the demand of industrial sand.
Step 4: acid leaching
Dilute acid has a remarkable effect on removing iron and aluminum, while concentrated sulfuric acid and aqua regia are used to remove titanium and chromium. Generally, mixed acids composed of the above acids are used to remove impurity minerals. The control of various factors in the process of acid leaching should be based on the requirements of timely final grade, and the concentration, temperature and dosage of acid should be reduced as much as possible to realize timely purification with lower mineral processing cost.