Quartz sand is a common and wildly-used non-metal raw material. It is wildly used in glass, casting, ceramics, metallurgy, and chemical industries. The requirement of purification is strict in quartz mining. In this passage, we will introduce the quartz sand separations with common gangue minerals in quartz extraction. The common gangue minerals of quartz sand include hematite, magnetite, limonite, ilmenite, feldspar and other minerals.
Use the table of contents below to navigate through the guide:
Iron is the common impurities in quartz sand. The existing form are as follows: (1) existing in clay or kaolinized feldspar; (2) attached on the surface of quartz particles as iron hydroxide film; (3) existing in ilmenite and other heavy minerals; (5) existing in mica, hornblende and other mineral particles. The iron impurities exist complex in quartz sands, so is the separation technology. The separation methods mainly include:
Scrubbing is to remove the iron hydroxide films by the grinding of mechanical force and mineral particles in quartz extraction. It can remove the iron films, the adhesive impurities and a part of iron in clay feldspar. In this separation technology, the factors influencing scrubbing effort include the structure and characteristics of scrubbing machine, configuration form, scrubbing time, scrubbing concentration and so on. The scrubbing equipment should be chosen according to the characteristic of quartz sand and the experiment result. The scrubbing concentration is generally 50%~60%. The scrubbing time subjects to Initial product quality requirements, which should be determined by experiment.
Magnetic separation is mainly to remove hematite, limonite, magnetite, black mica and other minerals in quartz extraction. If there are few iron impurities in quartz sand, a wet strong magnetic separator is chosen as the separation equipment. An important influencing factor is feeding fineness. The finer the mineral particles are, the better effect of iron impurities separation is.
Gravity separation the heavy minerals in quartz extraction, especially ilmenite. The consistency is over 2.9g/cm3. Spiral chute are the common gravity separation equipment in quartz extraction.
Flotation method can be separated into iron and mica separate flotation and iron-mica combined flotation in quartz extraction. The agent systems of the two flotation flow are different. Petroleum sulfonate and pine oil are coordinated to float iron, and vitriol is used as the pulp regulator.
Besides the four common extraction methods, the microbial extraction method is also a technology removing the film iron in quartz extraction. Aspergillus niger, penicillium and other microbe are used in the extraction. However, this technology is not used in large-scale industrial production.
Quartz has similar characteristics with feldspar, clay and other non-metal minerals. Therefore, it is quite different to separate feldspar in quartz separation. Washing - classification - deslime, flotation, and acid leaching are common technologies.
(1)Washing - classification - deslime
For quartz sand with a large number of clay minerals, washing - classification - deslime is an effective way of removing clay minerals in quartz extraction. It is generally used before the quartz extraction as the preparation of edulcoration.
The flotation of quartz sand can be divided into flotation with fluorine and without fluorine. Flotation with fluorine uses cation collector and HF as an activator. Flotation without fluorine uses vitriol or muriatic acid as the activator and responsible collectors are used to separating the feldspar. Under similar conditions, muriatic acid as an activator has a better effect than vitriol.
Because of the stable properties of quartz, acid leaching is also an effective way to remove impurities in quartz sand. The common acids include vitriol, muriatic acid, nitric acid, etc. It is affected by the concentration of acid dosage acid leaching time-temperature slurry agitation and other factors.
The above are the common separation of quartz sand and common gangue minerals in quartz extraction. To be aware of that the quartz sand of different mine has different mineral compositions. In practical production, the reasonable mineral processing technology should be determined by mineral processing experiment. The suitable processing flow can guarantee nice economical efficiency.