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Yuan Lei Small Classroom | Production of High Purity Quartz cannot be separated from these 4 technologies!

Release time:

2024-01-29 09:35

 

Yuan Lei Small Classroom | Production of High Purity Quartz cannot be separated from these 4 technologies!

 

The processing of quartz ore into high purity quartz is the process of separating various impurities in quartz raw materials as much as possible.Firstly, the quartz mineral and the gangue mineral monomer are separated by crushing and grading to obtain the corresponding quartz particles, and then the targeted processing technology is selected according to the occurrence state of impurity elements in quartz to effectively separate the independent mineral impurities, inclusion impurities and lattice impurities from quartz.

 

1. Crushing-grading pretreatment technology

 

In the process of high purity quartz processing, the crushing-classification pretreatment, one is to make the effective monomer dissociation of quartz and gangue minerals and the release of fluid inclusions, and the other is to provide raw materials with suitable particle size range for the subsequent quartz purification processing.

 

(1) Crushing

 

In the process of quartz crushing, the effective monomer dissociation of the vein mineral in quartz should be considered, and the secondary pollution of quartz should be reduced. In order to avoid secondary pollution of quartz by iron impurities in the crushing process, it is generally used.Zirconium ball, agateAs a grinding medium.

 

thermal crushingAs a commonly used process in quartz crushing, it not only reduces the hardness and crushing energy consumption of quartz ore, but also reduces the possibility of secondary pollution of quartz by reducing the contact time between quartz and grinding medium. At the same time, micro cracks are produced on the surface of quartz, which is conducive to the chemical purification of quartz.

 

high voltage pulse crushingThe shock wave generated by the high-voltage discharge in the quartz block makes the quartz more easily broken along the crystal boundary containing impurities, which is beneficial to the exposure of impurities in the quartz.

 

(2) Classification

 

Classification is the process of sorting particles according to their specific gravity, shape or size. High purity quartz not only has strict technical requirements for purity, but also has strict requirements for particle size distribution.

 

Classification can also separate some fine-grained slime impurities. Because quartz has higher hardness than iron-bearing minerals, gangue minerals are more easily ground under the same crushing conditions. SiO in quartz sand2The grade decreases with the finer grain size of the quartz sand.

 

2, Quartz CCP associated independent mineral separation technology

 

Quartz can be co-associated with a variety of minerals, color separation, scrubbing, gravity separation, magnetic separation and flotation methods are currently the most effective methods to separate co-associated independent minerals from quartz.

 

 

The most common method for separating mineral impurities in quartz ismagnetic separation and flotation. Multi-stage strong magnetic separation can not only separate the strong magnetic and weak magnetic mineral impurities from quartz, but also have a certain separation effect on magnetic mineral inclusions and conjoined organisms in quartz. Silicate minerals such as mica and feldspar are one of the main sources of aluminum impurities in quartz, which are often separated by flotation because of their similar physical and chemical properties with quartz. In order to effectively reduce the aluminum impurity content in quartz, multiple selection is essential.

 

The type, content and occurrence state of mineral impurities in natural quartz are very complex,Need according to the nature of quartz raw materials to choose targeted beneficiation combined processIn order to improve the separation effect of quartz and independent mineral impurities.

 

After pretreatment and physical separation, most of the independent mineral impurities in quartz have been separated, SiO2The content can generally reach about 99.9%, but it does not meet the technical requirements of high purity quartz. This is mainly becausePretreatment and physical separation only have a significant effect on the separation of quartz and independent mineral impurities, and have little effect on reducing the inclusion impurities and lattice impurities in quartz..

 

3. Separation technology of inclusion impurities and quartz

 

Almost all natural quartz minerals contain mineral inclusions and fluid inclusions, and the existence of a large number of inclusions not only increases the difficulty of processing high purity quartz, but also limits the quality of high purity quartz.

 

(1) Mixed acid dissolution of mineral inclusions

 

Mineral inclusions mixed acid dissolution using quartz can only be dissolved in hydrofluoric acid, and other mineral inclusions impurities can be dissolved by acid characteristics, to achieve the separation of quartz and impurities, commonly used acids are sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid and so on.

 

 

 

(2) High temperature bursting of fluid inclusions

 

Quartz in the process of high temperature roasting, with the increase of temperature when the internal pressure of fluid inclusions is greater than the quartz on the inclusions bound pressure, the fluid inclusions suddenly burst internal impurities can be released, and then the subsequent acid cleaning can dissolve the fluid inclusions internal impurities.

 

(3) Chlorination degassing

 

Chlorination degassing is heating quartz to 1000~1500 ℃ and introducing Cl2The high temperature treatment method of HCl or mixed gas can not only volatilize the metal impurity elements into gaseous chloride salt at high temperature, but also have a certain removal effect on the fluid inclusions in quartz.

 

4. Lattice impurity removal technology

 

In the completely pure quartz crystal contains only Si-O bonds, but due to the existence of the phenomenon of like substitution, natural quartz is introduced a large number of metal-oxygen (Me-O) bonds, which is one of the main sources of impurities in natural quartz minerals.

 

In the process of acid leaching purification of quartz, TerryB et al. believe that the Me-O bond energy and nature of the quartz lattice determine the ease of separation of metal impurity elements:
  • Me(Li+、 Na \ n+, K+)-O bond has the smallest energy and is most easily destroyed, but it cannot be effectively removed because alkali metal ions play a charge balancing role in quartz;

  • Me (Faith3 ICalICu2 、Ca2 、Mn2 etc.)-O bond energy is second, which is the lattice impurity element that is easier to remove from quartz;

  • Me(Al3 Ti Title4 )-O bond energy is larger, Al and Ti replace Si in quartz lattice to form new [AlO4]、[TiO4] is the most difficult crystal lattice impurity element in quartz.

 

There are many different crystal forms of quartz in nature. In the process of crystal transformation of quartz, the crystal structure of quartz will also change, and the impurities existing in the crystal lattice may migrate and diffuse to the surface of quartz particles, which increases the possibility of removal. At a high temperature of 1500 ℃, the phase transformation of quartz to cristobalite will lead to bond breakage and recombination, and the quartz lattice will expand, which is conducive to the migration and diffusion of metal impurity elements to the surface of quartz. Compared to the vacuum atmosphere roasting,nitrogen atmosphere roastingThe conversion rate of quartz to cristobalite is greater, and the migration and diffusion efficiency of impurity elements in quartz lattice may be higher.

 

chlorination roastingAt a temperature lower than the melting point of quartz, the impurity components in quartz and chlorinating agent are converted into chlorides and volatilized. Quartz has crystal transformation during high-temperature chlorination roasting, which makes the metal ions in quartz lattice migrate and diffuse to the surface of quartz, and HCl and NH4Cl and Cl2Such as chemical reaction into volatile components to achieve separation from quartz, but also to prevent the impurity elements in the cooling process of re-migration and diffusion into the quartz lattice.

 

Generally speaking, the technology of processing high purity quartz with natural quartz minerals has gradually matured.Pretreatment is mainly to fully dissociate and expose the impurities in natural quartz, and the effect of physical mineral separation of quartz and associated independent mineral impurities is significant.Inclusions and lattice impurities determine the limits of quartz ore purification processingAlthough the removal technology of these two impurities has been studied for a long time, the effect is not good, and it is the focus of high purity quartz processing research in the future.

 

Quartz, impurity, mineral, encapsulation, lattice, separation, crushing, technology, element

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