How to extract silica sand from kaolin tailings?

This paper describes in detail the method of extracting silica sand from sandy kaolin tailings, which can make full use of tailings and improve the application value of kaolin tailings. Its silica sand concentrate fully meets the requirements of glass quartz sand index.

Kaolin and its tailings

Kaolin is an important non-metallic mineral material. It is not only a necessary raw material for building materials, light industry and other traditional industries, but also a basic material for the development of modern industry. Kaolin mineral resources are continuously exploited and utilized, and a large number of tailings will be produced in the process of mining and processing of kaolin, and the number of tailings will increase year by year. The continuous accumulation of tailings occupies a large amount of land, which affects the ecological environment and also causes the waste of mineral resources.

The treatment methods of Kaolin Tailings mainly include: building tailings reservoir, in-situ stacking and reclamation. Tailings stocks are used to occupy cultivated land. With the development of production, the pressure of tailings reservoir is increasing. There are still some potential safety hazards in tailings reservoir, which can not be solved fundamentally. Reclamation and reclamation must be carried out after partial exploitation of resources, and the cost is very high. Therefore, rational utilization of Kaolin Tailings and turning waste into treasure are important ways for sustainable development of kaolin processing industry.

Quartz Sand in Kaolin

It is found that the content of quartz sand in sandy kaolin ore is high (70-80%). Therefore, further processing of sandy Kaolin tailings to prepare high purity quartz sand can be used in other industrial fields, which can not only absorb the accumulated kaolin tailings, but also form good economic and social benefits.

At present, some kaolin processing enterprises use kaolin tailings as raw materials to prepare quartz sand with a certain purity through complex technological sand washing plant processes such as mixing, concentration, grinding, grading and flotation, and apply it to building blocks, glass-ceramics and other materials. However, the above methods have some problems, such as complex processing process, large energy consumption, dust pollution and poor purity of quartz sand.

Extraction of glass quartz sand from Kaolin Tailings

In order to overcome the shortcomings and shortcomings of the existing technology, Sinonine developed a method for preparing quartz sand for glass production from kaolin tailings. The specific process flow is as follows:

Water is added to Kaolin Tailings and the suspension with solid content of 30-40% is obtained by mixing and dispersing the slurry with frequency conversion speed regulating disperser. The suspension was pre-classified by centrifugal classifier, and fine sand with tailings size less than 0.7 mm and coarse sand with tailings size larger than 0.7 mm were obtained. Coarse sand with particle size greater than 0.7mm is grinded by rod mill to obtain slurry. Fine sand with particle size less than 0.7mm is obtained by centrifugal classifying equipment. The coarse sand is returned to rod mill for grinding again, and the tailings are treated into fine sand with particle size less than 0.7mm in many cycles.

Fine sand with particle size less than 0.7 mm was classified by hydraulic classifier, and fine sand with particle size of 0.1-0.7 mm was obtained. Then fine sand with particle size of 0.1-0.7 mm was put into high gradient magnetic separator for impurity removal and purification, and fine sand with Fe2O3 content of 0.08wt% was obtained. Dry quartz sand concentrate was obtained by dewatering fine sand after impurity removal and purification.

This quartz sand production process is an effective method to prepare glass quartz sand from kaolin tailings. It belongs to a simple deep processing technology without chemical reaction. It is a simple physical processing process with no pollution to the environment and low energy consumption. Compared with the traditional technology of recovering quartz sand from kaolin tailings, the comprehensive energy consumption can be reduced by 10-30%.

Extraction processing of quartz sand from Kaolin Tailings

Water was added to kaolin tailings, and the suspension with solid content of 30-40 wt% was obtained by mixing and dispersing at high speed with frequency conversion speed regulating disperser. The speed of frequency conversion speed regulating disperser was controlled to 1000rpm. The tailings were ground to less than 0.7 mm by closed-circuit grinding system formed by bar mill and centrifuge. The fine sand with particle size less than 0.7m was treated by hydraulic classifier, and the fine sand with particle size of 0.1-0.7mm was obtained. Then the graded fine sand was added to the high gradient magnetic separator for impurity removal and purification. The magnetic field intensity was 13000 Gauss. Dry quartz sand products were obtained by dewatering fine sand after purification and impurity removal. After testing, the analysis results of quartz sand products are as follows:

It can be seen from the above table that the quartz sand prepared by this method meets the requirements of the national glass industry for quartz sand.

Suggestion

Because of the different properties of kaolin in different areas, the occurrence of quartz sand in kaolin is also very different. Before processing, customers need to study the mineral processing technology in advance to determine the best quartz sand extraction process.

For more informations about kaolin and silica sand , please visit Sinonine website showing details of mineral processing equipments.