Today, Fodamon engineers use many years of beneficiation experience to explain the beneficiation method of mica for you. The beneficiation of mica ore is the enrichment process of raw mica. Raw mica refers to any thickness mica crystal with a contour area greater than or equal to 4cm2 in the raw ore. The content of raw mica in raw ore is called the ore content of raw mica, which is usually expressed by the weight of raw mica per unit ore volume (kg / m3). The ratio of the total weight of raw mica in the concentrate obtained by beneficiation to the total weight of raw mica in the raw ore is called the recovery rate.
In industry, mica natural crystal is directly used to process the required products. The larger the flawless mica crystal, the higher its economic value. Therefore, in the process of mica ore beneficiation, it is necessary to protect the natural mica crystal from damage as much as possible.
At present, the beneficiation of flake mica with crystal contour area greater than 4cm2 is mainly carried out according to the differences in shape and friction coefficient between mica crystal and gangue. The commonly used methods include manual selection, friction selection and shape selection. For broken mica with crystal contour area less than 4cm2, it is mainly sorted according to the difference between its physical and chemical properties and gangue surface, and the method adopted is flotation method.
(1) Flake mica beneficiation method and its process
a. Hand selection
Workers pick the mica that has been separated by monomer on the mining face or ore pile at the pit mouth; The conjoined body of mica and gangue is broken with a hammer, and then the mica is selected.
b. Friction beneficiation
According to the difference between the sliding friction coefficient of flake mica crystal and the rolling friction coefficient of round gangue, mica crystal and gangue are separated. One of the equipment used is inclined plate sorter. The machine is composed of a group of metal inclined plates. Each inclined plate is 1350mm long and 1000mm wide. The inclination of the next inclined plate is greater than that of the previous inclined plate. A gap for collecting mica crystals is reserved at the lower end of each inclined plate, and its width decreases in turn according to the arrangement order of inclined plates. A triangular weir plate is installed at the front edge of the gap. In the process of sorting, large gangues roll down to the pile; Mica and small vein stones are blocked by the weir plate and fall down an inclined plate through the gap. Repeat the above process on the inclined plate in turn to gradually separate mica and gangue. At present, the friction beneficiation process and equipment are not perfect, so this method has not been widely used in mica ore beneficiation.
C. Shape beneficiation
According to the different shapes of mica crystal and gangue, the ability of passing through the sieve slot and sieve hole is different in screening, so that mica and gangue are separated. When sorting, a screen with more than two layers of different screen surface structures is adopted. Generally, the screen of the first layer is strip; The screen of the second layer is square. When the raw ore enters the screen surface, due to vibration or rolling, flake mica and small gangue can leak from the strip screen joint to the second screen surface; Because the second layer is lattice sieve, gangue can be screened off and flake mica can be left. Shape beneficiation method has the advantages of simple process, less equipment, high productivity and good separation effect, so it has been widely used in mica mines.
(2) Beneficiation method and process of crushed mica
a. Flotation
According to the different surface physicochemical properties of mica and gangue. The ore is broken and grind to separate the mica monomer. Under the action of the agent, the mica becomes a foam product and separates from the gangue. Mica flotation can be carried out in acidic or alkaline pulp. The cations of long-chain acetic amines and anions of fatty acids are the collectors of mica. In the mica flotation process, three-stage roughing and three-stage cleaning are required to obtain mica concentrate. Therefore, mica ore flotation is used to recover mica and fine mica below 14 mesh in pegmatite and mica schist. In China, mica ore flotation has not been applied in production.
B. Wind selection
Mica air separation is mostly realized by special equipment. The process is generally: crushing → screening and classification → air separation. After the ore is crushed, mica basically forms a sheet shape, while gangue minerals such as feldspar and quartz are massive particles. Therefore, the selected materials are pre divided into narrow particle sizes by multi-level classification, and the special air separation equipment is used for separation according to the difference of their suspension speed in the air flow. The air separation method is suitable for areas with lack of water source and has been used in actual production.
What are the mica beneficiation reagents: they are sorted according to the different surface physicochemical properties of mica and gangue. The ore is broken and grind to separate the mica monomer. Under the action of the agent, the mica becomes a foam product and separates from the gangue. Mica flotation can be carried out in acidic or alkaline pulp. The cations of long-chain acetic amines and anions of fatty acids are the collectors of mica. The main agents are sulfuric acid, sodium hydroxide, water glass, dodecylamine, oxidized soap, etc. In the mica flotation process, three-stage roughing and three-stage cleaning are required to obtain mica concentrate. Therefore, mica ore flotation is used to recover mica and fine mica below 14 mesh in pegmatite and mica schist. In China, mica ore flotation has been widely used in production.