Silica Sand Washing Plant | Quartz Processing Plant

The silica sand washing plant mainly includes: quartz stone crushing and sand making, washing, grading, desliming, washing, magnetic separation, flotation, acid leaching, etc., to remove a small or trace amount of impurities in the silica sand, and obtain refined silica sand or used for glass. , ceramics, construction, chemical industry and other high-purity silica sand.

(i) Crushing and Silica Sand Manufacturing

The quartz stone is first sent to the jaw crusher for coarse crushing, and then reasonably screened by the circular vibrating screen, and then sent to the cone crusher for medium and fine crushing. The unqualified materials are returned to the cone crusher after the same screening. Quartz stones that meet the sand making requirements are driven by the conveyor into the sand making machine for sand making and shaping to obtain 0-5mm silica sand.

(ii) washing, grading and desliming

The quartz stone material contains a large amount of clay minerals, so the silica sand needs to be washed and deslimed.

【Application scope of water washing】: It is suitable for minerals that can be easily washed to remove clay. Generally, the particle size of silica sand is 0.075-1.0mm, while the particle size of clay minerals is less than 50μm, generally less than 20μm.

【Washing】: Different sand washing equipment can be used for cleaning, such as washing chute, hydrocyclone, up-flow hydraulic classifier, etc. At present, the up-flow hydraulic classifier is mostly used, and the fine minerals are discharged from the top overflow in the form of mud, while the coarse and heavy particles are discharged from the bottom.

【Screening】: Coarse sand can be removed by wet sieve of 0.5-1.0mm, so that silica sand and clay minerals can be separated from each other in water medium.

(iii) Scrub

Scrub is to remove film iron, cohesive and muddy impurity minerals on the surface of silica sand by mechanical force and friction between sand grains, and further grind unaggregated mineral aggregates. After the classification operation, the silica sand will be further purified.

At present, there are mainly mechanical scrubbing, stick scrubbing, medicinal high-efficiency strong scrubbing and ultrasonic scrubbing. The mechanical scrubbing equipment is a rotary scrubber with strong scrubbing capacity: 200-250T/H.

(iv) Magnetic separation

Magnetic separation is mainly used to remove magnetic minerals from silica sand. For example, weak magnetic minerals such as hematite, limonite, and biotite can be removed by a strong magnetic separator, while strong magnetic minerals such as magnetite, titanomagnetite, and pyrrhotite can be removed by a weak magnetic separator.

(v) Flotation

The composition of silica sand is complex. In addition to iron-bearing minerals, there are often mica, feldspar and clay minerals. Some impurities in silica sand, such as feldspar, mica, etc., cannot be removed by magnetic separation, but can be separated by different collectors. Generally speaking, after washing, desliming, magnetic separation and flotation, the purity of silica sand can be increased to 99%.

(vi) Pickling

Acid leaching of silica sand for iron removal is based on the fact that silica sand is insoluble in acid (except HF), and iron-containing impurity minerals can be dissolved by acid solution, so iron minerals can be removed from silica sand. .

The purity of silica sand after flotation can reach 99.5-99.9%. If the silica sand is to be further purified, the impurities in the form of speckles and inclusions on the surface of the silica particles must be subjected to an acid leaching treatment. According to the requirements of different industrial uses for different impurity minerals (Fe, Al, Ti, Cr) of silica sand, mixed acid leaching treatment with different concentrations and ratios is carried out.

In addition, acid leaching time, mineral particle size, and slurry agitation all affect removal efficiency. Therefore, various factors need to be reasonably controlled to reduce the cost of silica sand washing plants.