5 Kinds of Quartz Sand Purification Process

Quartz sand is a hard, wear-resistant and chemically stable silicate mineral. Because of its unique physical and chemical properties, quartz sand plays an important role in aviation, aerospace, machinery, electronics and IT industries.

There are few pure quartz sand in nature, and it is often accompanied by other impurity minerals. The mixing of these impurities will greatly reduce the value of quartz sand.

At present, quartz sand purification processes include scrubbing & desilting, magnetic separation, flotation, acid leaching, and microbial leaching.

Quartz Sand Scrubbing & Desilting

The grade of impurities in quartz sand is closely related to the particle size of quartz sand. The grade of silica will decrease as the particle size of quartz sand becomes finer, but the grade of impurity minerals such as iron and aluminum will increase.

Therefore, it is necessary to scrub the quartz sand ore before processing to remove the thin film iron and some muddy impurity minerals on the surface for preliminary purification.

Commonly used scrubbing equipment includes High Efficiency Agitator Washer, Spiral Chute Washer, hydraulic classifier, desliming bucket, vibrating screen, etc.

Quartz Sand Magnetic Separation 

Quartz sand is magnetically selected to remove some magnetic impurities in quartz sand.

Weak magnetic minerals such as hematite, limonite, and biotite can be removed with the help of a strong magnetic separator, while strong magnetic minerals such as magnetite can be removed with a weak magnetic separator.

In the magnetic separation process, the finer the particle size of the quartz sand, the better the iron removal effect. In addition, the iron removal effect is also related to the number of magnetic separations and the strength of the magnetic field.

Quartz Sand Flotation

Flotation is mainly used to remove non-magnetic impurity minerals such as mica and feldspar in quartz sand.

Mica impurities can be removed by flotation with cationic collectors at pH 3-4, while the effective separation of feldspar from quartz is a challenge.

At present, the separation of feldspar by quartz flotation is mainly carried out under acidic conditions. According to the different reagents used, it can be divided into fluorine flotation and fluorine-free flotation. Because flotation is carried out under acidic conditions, the anti-corrosion requirements of equipment are relatively high. 

Quartz Sand Acid Leaching

Quartz sand acid leaching method utilizes the characteristics that quartz sand is insoluble in acid, but acid solution can dissolve other impurity minerals, to remove iron, aluminum and other impurities on the surface of quartz sand to achieve further purification. However, the acid leaching method has certain difficulties in the process and requires high operation.

Quartz Sand Microbial Leaching

Microbial leaching to remove thin-film iron or impregnated iron on the surface of quartz sand is a new purification technology, but it is currently in the laboratory research stage and has not been used in large-scale production.

In actual production, the quartz sand purification process does not simply use one process. In order to better purify the quartz sand, a combination of multiple purification processes can be selected.