Quartz Sand Removal: How to Remove The Mica in Quartz Sand?

Published time:07 February 2023

Mica is one of the often associated minerals of quartz sand. For quartz sand, mica is an impurity. The removal of mica is an important part of quartz sand purification.


Quartz Sand


What is mica?

Mica is a general term for mica group minerals. It is an aluminosilicate of metals such as potassium, aluminum, magnesium, iron, and lithium. It is a layered structure and a monoclinic crystal system. The crystals are pseudo-hexagonal flakes or plates, occasionally columnar. The lamellar cleavage is complete, with glass luster, and the chips are elastic. There are biotite, phlogopite, muscovite and so on.


How to remove mica?

1. Crushing, screening, and sorting

The process of this method is simple, with less equipped equipment, high production efficiency, and strong separation ability. The required separation equipment is the same as the leading processing equipment of the sand and gravel processing system and can be applied to the sand and gravel processing system. Mica separation can be realized by targeted mica-removing transformation on the ordinary crushing and screening process.

2. Shaker table gravity separation

The shaking table gravity separation has a simple process and good separation ability. Still, it needs additional equipment such as a shaking table, high energy consumption, large water consumption, and takes up a lot of space. Before considering the shaking table equipment, the sand and gravel processing system must carry out the shaking table sorting test on the crushed ore and weigh the pros and cons according to the sorting effect.

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3. Magnetic separation

Some mica has weak magnetism and can be removed by magnetic separation, which can remove iron-containing mica. Before considering the magnetic separation operation, the sand and gravel processing system need to conduct a chemical analysis on the properties of the raw sand and gravel and the mica minerals contained in it to determine whether it contains iron and conduct a magnetic separation test according to the iron content.

4. Wind Separation

The mica winnowing method is based on the difference in the settling velocity of mica and gangue in the airflow. Generally, the process of “crushing and grading winnowing” is adopted, and special equipment is required for winnowing. This method must cooperate with screening and other ways to obtain the mica separation effect.

There are many types and models of wind separators, and the technology is mature, which can be directly used in sand and gravel processing systems. The principle of air separation is similar to that of the sand and gravel system dust collector, which requires the raw ore to be kept dry, so the air separation method is only suitable for the dry production of sand and gravel processing systems. According to data, when the moisture content of raw ore exceeds 2%, fine sand is easy to adhere to the surface of mica, which will cause blockage of the vibrating screen at each section and affect the removal effect of mica.

5. Flotation Separation

We carry out the separation according to the difference in the physical and chemical properties of the mica and quartz sand surfaces. Crush the quartz ore and ground to dissociate the mica monomer. Under the action of the mineral dressing agent, the mica becomes a foam product and separates from the gangue. We can carry out mica flotation in acidic or alkaline pulp, and the cations of long carbon chain amine acetates and anions of fatty acids are mica collectors.


Flotation machine
Flotation machine


It mainly uses the flotation method in the recovery of crushed mica and fine-grained mica in the sand and gravel industry, especially the mica resources in the tailings. In actual production and application, it should accord the nature and characteristics of the ore to determine the preliminary technological process and then enrich and optimize through a series of condition tests to obtain better technical and economic indicators.

The flotation method has strict requirements on the pH value of the pulp, and a large number of regulators (pH regulators and dispersants), collectors, inhibitors, and other chemical reagents need to be added. The flotation method consumes a lot of water, is costly, and is difficult to treat wastewater.


Due to the particularity of the sand and gravel processing system, physical sorting to remove mica is a more reasonable choice. If choosing the crushing and vibration screening to separate the mica, it can use the existing crushing and screening equipment of the sand and gravel system. This method has specific requirements for crushing and screening equipment. The sand and gravel processing system containing more mica should take a series of targeted crushing and screening tests before selecting the equipment and determining the processing technology.

Magnetic and shaker gravity separation requires more equipment and a more significant site, and the production cost is high. The sand and gravel processing system need to decide whether to adopt this method according to the nature of the sand and gravel raw material and the results of the previous test. The separation principle of air separation mica is simple, and the production cost is moderate. It is more practical for dry-process sand and gravel processing systems. Mica separation can be carried out by selecting appropriate air separation equipment and air separation processes.

Mica will have a certain impact on the quality of the finished photovoltaic glass quartz sand, such as affecting iron and aluminum content, etc. The amount of mica removed depends on the quality requirements of the finished sand.

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