How to Extract Mica | 6 Mica Mining Methods

Mica is a common silicate mineral with a layered structure and a monoclinic crystal system. There are many types of mica minerals, including biotite, muscovite, phlogopite, lepidolite, sericite, etc., which are widely used in industry. Mica is also one of the main rock-forming minerals and often appears as associated minerals in various ore deposits. Therefore, the research on the recovery process of mica is of great significance in the comprehensive utilization of minerals. 

The difficulties in the separation of mica are mainly in the following aspects:

1. The properties of mica and its symbiotic minerals are similar, and it is difficult to obtain a good beneficiation effect by conventional beneficiation methods.

2. During the beneficiation process, care should be taken not to damage the flaky structure of mica.

3. The shape, area, thickness and other properties of mica in the ore are different.

4. There are great differences in the properties of mica ore from different deposits.

In view of the above difficulties, the beneficiation and recovery process of mica mainly includes hand separation, shape separation, friction separation, flotation, wind separation, gravity separation and so on. According to the different mica ore components and mica embedding patterns, the beneficiation and recovery processes are also different.

Hand separation is a method for separating large flake mica in the small processing plant. The separated mica is selected manually on the mining face or the ore heap at the mouth of the mine. Or the mica is selected by breaking the jointed body with a hammer. Although this method has a simple process and uses less equipment, it is labor-intensive.

The shape separation method utilizes the different shapes of lamellar mica crystals and gangue minerals to separate. This method mainly uses trommel screens and vibrating screens, which are generally more than two layers of screening equipment with different sieve holes. When the raw ore enters the screen surface and is subjected to vibration or rolling, the flaky mica stays on the screen surface. Small pieces of flaky mica and gangue minerals enter the second screen surface. Then the gangue falls under the sieve to realize the separation of mica and gangue. The shape separation method has a simple process, less equipment and high production efficiency, and is a commonly used separation method in mica processing plants.

The friction separation method is also one of the methods for recovery flaky mica. It uses the different friction coefficients of mica crystals and gangue blocks for sorting. The equipment used includes metal sheet separators, spiral classifier, and inclined plate separators etc. Although this method has high production efficiency, when the ore thickness is large, gangue and mica with similar shapes are easily mixed in. And the equipment and process are still not perfect, so it has not been widely used.

The flotation method can be applied to flake mica and crushed mica, and can be divided into acidic cation flotation method and alkaline anion-cation flotation method.

Acidic cationic flotation can effectively recover coarse-grained mica above 14 mesh. Before separation, it needs to be deslimed on a 150~200 mesh screen. Sulfuric acid is used as a pH regulator to suppress quartz, and the flotation effect is better at a pH of about 0.4. It can be recovered using long carbon chain organic collectors such as ammonium acetate as cationic collectors.

Alkaline anion-cation flotation can float mica minerals above 20 mesh. It allows a small amount of slime in the pulp, but it needs to remove the sticky minerals before separation. Sodium carbonate and calcium lignosulfonate are used as pulp inhibitors, among which calcium carbonate is also used as a pH regulator, and calcium lignosulfonate also acts as a pulp dispersant. When the pH is between 8.0 and 10.5, the recovery effect of mica is better, and its anion collector is a combination of fatty acid and fatty acid. When there is slime in the pulp, it is necessary to add ammonium acetate as a cationic collector to increase its selectivity.

The wind separation method is suitable for crushed mica minerals, and the general process is crushing-classification-wind separation. When the ore is crushed, the mica forms flakes, while the quartz and feldspar gangue minerals are in the form of massive particles. Multi-level classification can be used to classify the selected materials into narrower particle sizes. According to their suspension speed in the airflow Differences are sorted. The separation efficiency of the wind separation method is not high, and generally requires multi-stage separation or is used in conjunction with other methods.

The gravity separation method is a common method for separating mica and gangue minerals. It utilizes the density difference between mica and gangue. Commonly used equipment includes shaking table, spiral chutes, etc., and can be used in combination with other methods to improve the separation effect.

The above are the 6 mica separation methods. It should be noted that the properties of mica minerals in different deposits are quite different. It is necessary to scientifically and rationally formulate the process flow through beneficiation experiments to avoid economic losses and resource waste caused by blind selection.

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