Mineral processing is the use of minerals in the physical or physical and chemical properties of different mineral processing equipment to separate the useful minerals and gangue minerals in the ore, and to achieve a relatively enriched process of useful minerals. Mineral processing is the study of mineral separation and is a technical science that separates, enriches and comprehensively utilizes mineral resources. Mineral processing is the use of minerals in the physical or physical and chemical properties of different mineral processing equipment to separate the useful minerals and gangue minerals in the ore, and to achieve a relatively enriched process of useful minerals. Mineral processing is the study of mineral separation and is a technical science that separates, enriches and comprehensively utilizes mineral resources. Non-metallic mineral most prominent feature is the multi-minerals. At present, the development and utilization of the world's more than 200 kinds of non-metallic minerals (including precious jade), China has discovered 100 kinds of economic value of non-metallic minerals. Another outstanding feature of non-metallic minerals is that the nature of each mineral is very different and has little commonality. For example, in this large family, there are both the hardest diamonds in nature and the softest talc ; there are precious gems that are valuable in the city, and a large amount of cheap soil, sand and stone. The difference between physical properties and value determines that mining, mineral processing and processing methods vary widely. In addition, most non-metallic ore is a useful mineral aggregate or rock for utilization. In the beneficiation operation, the useful mineral crystals are protected, and the use value of the mineral is not reduced, which becomes the main principle for determining the beneficiation process and equipment selection. Non-metallic ore dressing is much more complicated than other solid minerals. The beneficiation process is usually a continuous production process consisting of pre-election ore preparation, sorting operations and post-selection dewatering operations. In order to select useful minerals from the ore, the ore must first be comminuted to allow the useful minerals and gangues to dissociate from the monomer. Sometimes in order to meet the special requirements of the material size of the subsequent operations, it is necessary to add a certain crushing operation in the middle. Pre-selection preparations are usually divided into two stages: crushing and screening operations and grinding and grading operations. The crusher and the sieving machine are mostly combined operations, and the mining machine and the classifier often form a closed circuit cycle. They are the main mechanical devices that make up the crushing workshop and the grinding workshop. The sorting operation is a process in which the ore that has been dissociated from the monomer is separated by a suitable means to separate the useful mineral from the gangue. The most common methods are: (1) Floating ore dressing method (referred to as flotation method). Flotation is a method of separating minerals in a flotation machine by adding appropriate chemicals depending on the wettability of the mineral surface. It is widely used to process most ore. (2) Magnetic separation method. Magnetic separation is a method of sorting in a magnetic separator according to the difference in mineral magnetic properties. Mainly used to treat ferrous ore and rare metal ore. (3) Gravity beneficiation method (referred to as re-election method). Re-election is the method of sorting by using the difference in the speed of movement and the trajectory of the medium in different medium (water, air or heavy medium). It is widely used to select tungsten, tin , gold and iron , manganese and other ores, other non-ferrous metals, rare metals and non-metallic ores are also commonly used for re-election. Reselection is performed in various types of reselection devices . In addition, there are methods for beneficiation based on the conductivity, friction coefficient, color and gloss of the mineral, such as electro-selection, friction dressing, photo-selection and hand-selection. Most of the selected products contain a lot of water, which is bad for transportation and smelting. Therefore, before smelting, it is necessary to remove moisture from the beneficiation product. Dewatering operations are often carried out in the following stages: (1) Concentration. Concentration is the operation of removing solid water from the beneficiation product by gravity or centrifugal force to remove part of the water. Concentration is usually carried out in a concentrator. (2) Filtration. Filtration is the operation of solid-liquid separation by passing the slurry through a spacer layer that is permeable to water and does not penetrate the solid particles. Filtration is a further dewatering operation after concentration and is generally carried out on a filter. (3) Drying. Drying is the final stage of the dehydration process. It is based on the principle of heating and evaporation to reduce the moisture in the product. However, it is only used when the dehydrated concentrate needs to be dried. Drying operations are generally carried out in a dryer, and other drying devices are also used. The auxiliary workshop consisting of processes such as concentration, filtration, and drying is called a dewatering workshop. The purpose of mineral processing and purification of non-metallic minerals is as follows: (1) Separating the useful minerals from the gangue minerals in the ore to enrich the useful minerals; (2) removing harmful impurities from the ore; (3) Recover associated minerals as much as possible, and comprehensively and economically and comprehensively utilize mineral resources. At present, the commonly used methods for purifying non-metallic minerals are flotation method, re-election method, magnetic separation method, electric separation method, chemical beneficiation method, photoelectric sorting method, friction washing and mineral processing methods of ultrafine particles which have appeared in recent years. Non-metallic ore sorting and purification features: (1) The purpose of non-metallic ore dressing is usually to obtain a product with certain physicochemical properties, rather than to obtain one or several useful elements in the mineral. (2) The non-metallic ore beneficiation process should maintain the crystal structure of useful minerals as much as possible so as not to affect their industrial use and use value. (3) The calculation of non-metallic ore dressing index is generally based on the content of useful minerals, and the oxide grade and the recovery rate of useful minerals are often expressed in the form of oxides, rather than the content of certain elements in the mineral. (4) Non-metallic ore beneficiation purification not only enriches useful minerals, removes harmful impurities, but also grinds and classifies products of different specifications. 1. Picking and friction washing (1) Picking: Picking is a beneficiation method that separates useful minerals and gangue minerals by utilizing physical characteristics such as surface characteristics, optical properties, electrical properties, magnetic properties, radioactivity, and ore absorption and reflection properties of ore. Sorting is mainly used for the sorting of bulk and granular materials, such as removing large waste rock or picking up large rich ore. The upper limit of the sorting granularity can reach 250-300 mm, and the lower limit is 10 mm. For individual precious minerals (such as diamond), the lower limit can be 0.5-1 mm. For the sorting of non-metallic minerals, the sorting has a special effect and can be used to pre-enrich or obtain the final product. For example, for the original diamond ore, the sorting can be used to separate the diamond and the waste rock in advance, and the rough selection and selection of the diamond are adopted. Picking can obtain diamond finished products. Similarly, for non-metallic minerals such as Dali right, limestone , gypsum , talc, kaolin , asbestos, etc., the final product with higher purity can be selected. Picking can be divided into the following two ways: A: Manual picking: Picking out ore and waste rock by hand according to the appearance characteristics (color, gloss, shape, etc.) between the ore and waste rock. There are two types: forehand selection (using useful minerals from materials) and backhand selection (removing waste stones from materials). A method mainly used for mechanical sorting or bad can not guarantee the quality of the ore, such as long fibers chosen asbestos, mica flake, from the coal-based culling kaolinite bulk waste rock (quartz, feldspar) and the like. Hand selection is the easiest way to pick, but it is labor intensive and inefficient. Manual picking is generally performed on hand-selected fields, fixed grid screens, hand-selected belt conveyors, and hand-selected platforms. Common hand-selected equipments are hand-selected belts and hand-selected platforms. The hand-selected belt requires a flat belt with a width of no more than 1.2m, a speed of 0.2-0.4m/s, an inclination of no more than 15 degrees, a height of 0.7-0.8m from the ground, and a height of 2m from the ground. The hand selection station is generally based on an area of ​​3.2 m2 for 4 people. B: Mechanical picking: According to the appearance characteristics of the ore and the difference of the ore reflected by the visible light, X-ray, γ-ray or the natural radiation ability of the ore, the ore separation method of ore and gangue separation is realized by means of the instrument. Such as radioactive sorting of gamma rays; ray absorption sorting (gamma absorption method, x-ray absorption method, neutron absorption method); luminescence sorting (gamma fluorescence method, x fluorescence method, ultraviolet fluorescence method, infrared method); photoelectric sorting (surface photometry) Picking); electromagnetic picking. Which sorting method is adopted is more reasonable, mainly determined by the characteristics of the ore, the nature of the ore is different, and the sorting method is also different. (2) Friction Washing: Friction washing is a process for treating ore that is glued with clay or contains a lot of mud, including two operations of breaking and separating. Usually, the mineral is soaked in an aqueous medium, washed and mechanically agitated (if necessary, a dispersant is added), and the mineral particles adhered by the slime are dissociated and contaminated with clay by means of the friction between the minerals themselves. Phase separation is called friction washing. Scrubbing (frictional washing) can be used as a preliminary preparation for other purification operations or as a separate purification of minerals. 2. Gravity dressing Gravity ore dressing is referred to as re-election. It is based on the difference in density between minerals, in a certain medium flow (usually water, heavy liquid or heavy suspension), loosened by the force of fluid buoyancy, power or other mechanical forces, in gravity (or centrifugal force) and sticky Under the action of hysteresis, the mineral particles of different density (particle size) are stratified and transferred, so as to achieve the purification method of separation of useful minerals and gangue. With re-election, the greater the difference in density between the useful mineral and the gangue, the more favorable the sorting, and the smaller the sorting, the more difficult it is to sort. Re-election is usually carried out in a vertical gravity field, a sloped gravity field, and a centrifugal force field. In the process of re-election and purification, the factors affecting the re-election index are: mineral density, ore size and shape, medium properties, equipment type and operating conditions. 3. Flotation Flotation is a beneficiation method that separates minerals in a gas-liquid-solid three-phase interface system by utilizing the difference in mineral surface properties (hydrophobicity or hydrophilicity). The wetting of the surface of mineral particles is caused by the dipole polarity of the water molecular structure and the crystal structure of the mineral. The wettability is the degree to which the mineral is wetted by water. Minerals that are easily wetted by water are called hydrophilic minerals, and minerals that are not easily wetted by water are called hydrophobic minerals. The wettability of the mineral determines whether the ore can adhere to the bubble when it collides with the bubble, that is, the wettability determines the natural floatability of the ore. Minerals with a strong surface wettability (hydrophilic minerals) have poor natural floatability; otherwise, natural floatability is good; the wettability of mineral surfaces—that is, the degree of hydrophilicity or hydrophobicity is usually measured by the contact angle. The flotation separation of ore minerals is limited by the natural floatability of the mineral surface. It is usually necessary to use a certain flotation agent to make the minerals easily contact with the bubbles, that is, to improve the floatability of the minerals, and the flotation agent is solid. The adsorption of the liquid interface affects the floatability of the mineral, which is affected by the electrical properties of the mineral surface; therefore, the electrical properties of the mineral surface are inextricably linked to its floatability. The following agents are commonly found in flotation processes: (1) Foaming agent. Organic surface active substances distributed at the water-air interface, such as commonly used pine oil, cresol oil, alcohols, and the like. (2) Collecting agent . Its role is to change the hydrophobicity of the mineral surface, allowing the floating mineral particles to adhere to the bubbles. According to their action properties, they are further classified into non-polar collectors (hydrocarbons), anionic collectors (such as fatty acids, etc.), and cationic collectors (such as fatty amines). (3) Adjusting agent. Including activators and inhibitors, changing the properties of the surface of the ore particles, affecting the role of minerals and collectors, and adjusting agents are also used to alter the chemical or electrochemical properties of the aqueous medium, such as changing the pH of the slurry and the collector therein. status. The conditioning agent is typically an inorganic compound. However, in practical applications, many organic flotation agents often have both foaming and trapping properties. One agent acts as a foaming agent in one process and in the form of a collector in another process. Appear, if classified by purpose, it will inevitably cause confusion. Therefore, when discussing or introducing the problem of flotation reagents, it is reasonable to use the basic classification of organic chemistry, or to classify functional groups of organic compounds, and to properly consider the use in flotation practice. 4. Magnetic separation and electrification Magnetic separation is a purification method in which different minerals are separated by using magnetic differences between minerals in an inhomogeneous magnetic field. Used for the selection of ferrous metal ores and the selection of colored and rare metal ores. The magnetic separation of non-metallic minerals is to remove magnetic impurities such as iron from non-metallic mineral raw materials to achieve the purpose of purifying non-metallic minerals. Electro-election is a beneficiation method that utilizes the electrical differences of various minerals to achieve mineral separation in a high-voltage electric field. It is widely used in the sorting of colored, ferrous and non-metallic minerals. (1) Mineral magnetic separation process: Magnetic separation is performed in a magnetic separation device . After the selected ore is fed into the sorting zone of the magnetic separation equipment; the mineral particles are subjected to the combined action of magnetic force and mechanical force (including gravity, centrifugal force, water flow force, etc.), and the magnetic particles with different magnetic properties are subjected to different magnetic forces. Since the combined force of magnetic force and mechanical force acting on each mineral particle is different, magnetic separation of magnetically strong minerals and weak magnetic minerals (non-magnetic minerals) is achieved. A: High gradient magnetic separation and superconducting magnetic separation a: High-gradient magnetic separation: The high-gradient magnetic separator is also a wet-type magnetic separator. It obtains large magnetic field forces in two ways, – the magnetic field strength H and the magnetic field gradient. The gradient is determined by the use of a special magnetically permeable medium, steel wool, which greatly increases its magnetic field force. b: superconducting magnetic separation: superconducting magnetic separator is to change its magnetic material from ferromagnetic to superconductor. The structure can be divided into three systems: superconducting magnetic system, refrigeration system and sorting system. B: The horizontal string reciprocating high gradient superconducting magnetic separator consists of a solenoid type superconducting magnetic system, a sorting tank, a ferromagnetic screen, a hydraulic reciprocating device and a machine base. Horizontal string tank reciprocating high gradient superconducting magnetic separator sorting process: during operation, the superconducting magnet is excited, and a sorting tank is located in the magnetic field cavity to give the pulp, capture the magnetic particles, and wash the magnetic medium. Another sorting tank is located in the corresponding magnetic screen cavity to wait for work. When the reciprocating canister withdraws from the magnetic field by the reciprocating transmission device, it reaches the corresponding magnetic screen cavity and punches out the magnetic particles on the medium. Another sorting tank, which was originally parked in the magnetic chamber, enters the human magnetic field and repeats the process of repeating the previous sorting tank. This method allows the superconducting magnet to work like a permanent magnet without consuming energy, minimizing the energy consumption of the refrigeration system. (2) Electrification: Electro-selection is performed in the electric field of the electric sorter. After the mineral particles are fed into the electric field, due to the difference in electrical conductivity, the ore particles in the electric field carry some kind of electric charge or a different amount of electric charge in some way. Thereby subject to different electric field forces to achieve separation. In addition to the electric field force in the electric field, the mineral particles are also combined by centrifugal force and gravity. The above is a review of the methods and characteristics of non-metallic mineral processing. The following is a further discussion on the development trend of non-metallic mineral processing in China. The development of mineral processing and products is a very promising field and the development direction of the non-metallic mineral industry. A mineral product is processed and made into a product, which is often worth a hundred times. At present, China's non-metallic minerals export situation is very good. In the past 10 years, the amount of foreign exchange earned by exports has increased year by year, but the structure of export products is unreasonable. Two-thirds are raw ore and primary processed products, low-priced raw ore exports, and high-priced imported manufactured goods. The cases are not uncommon. Therefore, it is imperative to develop processed products and adjust the product structure. Non-metallic minerals are a kind of continuously developing and constantly changing mineral resources. For some minerals or rocks, they are mines or mines. They are closely related to the science and technology and economic level at that time, as well as local resource conditions and mineral processing. It is closely related to the level of processing technology. The general development trend of non-metallic mineral dressing is: (1) Conventional mineral processing methods, process flow and equipment suitable for non-metallic mineral processing characteristics will be gradually promoted, applied and developed; (2) In order to meet the stricter quality requirements of non-metallic mineral raw materials for new ceramics, engineering plastics, optical fiber and other new materials, non-metallic ore dressing will move toward high-purity and ultra-fine technology fields; (3) Further development and promotion of high-efficiency beneficiation equipment; application and development of various mineral processing methods in the treatment of non-metallic ore refractory ore; various new technologies (such as superconducting, ultrasonic, laser, etc.) in non-metallic minerals Application in mineral processing and application of modern detection technology. 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