There are many methods and equipment for mineral dehydration, which are mainly divided into the following categories.
(1) Gravity dehydration: refers to dehydration achieved by relying on gravity. It is mainly used for dehydration of coarse-grained minerals and can remove free water. The main equipment includes natural gravity dehydration (dehydration bucket and dehydration bin) and gravity concentration dehydration (concentrator and sedimentation tank).
(2) Mechanical dehydration: refers to the separation of water and materials achieved by mechanical force, which can remove free moisture. The main equipment includes screening dehydration (vibrating screen), centrifugal dehydration (filter centrifugal dehydrator and sedimentation centrifugal dehydrator) and filtration dehydration (vacuum dehydrator, plate and frame filter press and pressure filter).
(3) Thermal energy drying: refers to dehydration that uses thermal energy to vaporize and evaporate water in minerals. It can remove capillary water, combined water and bound water in minerals. The main methods include thermal drying and sun exposure. Gravity dehydration equipment - thickener
The thickener is a mechanical equipment used for effective separation of solid and liquid suspensions. It is mainly used for concentrate concentration and tailings dehydration in metal, coal and other non-metal washing plants. , can also be used for the concentration and purification of all solid-containing slurries in chemical industry, environmental protection and other departments. When the concentrator works, it relies on the principle of gravity sedimentation to separate suspended solid particles in the slurry from the liquid, thereby achieving solid-liquid separation. Its purpose is to increase the solid concentration in the slurry. The deep cone thickener is mainly composed of a deep cone, a feeding device, a stirring device, a control box, a dosing device and an automatic control system. The slurry first enters the degassing barrel for treatment, and then is fed into the cyclone feeding box. After flocculation in the feeding barrel, the slurry enters the dense phase sedimentation layer. Through the re-flocculation, filtration and filter press of the dense phase sedimentation layer, the lower cone bottom discharges high To reduce the concentration of underflow, Yantai Xinhai Mining Machinery has successfully developed a high-efficiency deep cone multi-cone thickener, which has a large settling area and compression area and good concentration effect.
High-pressure thickener is a new type of high-efficiency solid-liquid separation equipment after high-efficiency thickener and deep cone thickener. It combines the characteristics of large processing capacity of high-efficiency thickener and high underflow concentration of deep cone thickener. It can effectively solve the problem of dehydration at the fine particle level. The underflow concentration is higher than that of the high-efficiency thickener, which can reach 45 to 50, and the diameter of the equipment is larger than that of the deep cone thickener, which is beneficial to improving the processing capacity of the equipment.
Mechanical dehydration equipment
Centrifugal force creates a pressure difference on both sides of the filter medium, with strong driving force and fast separation speed. For slurries with poor settling performance, an appropriate amount of flocculant needs to be added before filtration, but it is necessary to prevent the floc from adsorbing too much water, causing an increase in the water content of the filter cake; the centrifugal force field acts directly on particles and fluids, and centrifugal filtration dehydration technology can Effectively increase the filtration driving force, the filtration driving force and compression effect generated are much higher than vacuum, pressure and other filtration methods. The dehydration rate is high, the residual saturation of the filter cake is low, and the system is simple, operating energy consumption and operating costs Low. Its main equipment includes: sedimentation centrifugal dehydrator and sedimentation filter centrifugal dehydrator. Production practice has proved that the sedimentation centrifugal dehydrator and the sedimentation filter centrifuge are both effective in processing fine particles, but the two centrifuges cannot replace each other and each has its best use conditions. As a kind of equipment that uses centrifugal force to strengthen solid-liquid separation, hydrocyclone has the characteristics of simple structure, low cost, small footprint, large processing capacity, and high underflow concentration. It is used in tailings damming and tailings pre-concentration. , tailings enrichment recovery, tailings filling operations play a great role.
Filtration and dehydration
(1) Vacuum drum filter. Rotary drum filters have been widely used in various mineral processing industries, not only for alkaline leaching filtration and washing, but also for acid leaching processes, especially for solid-liquid separation in CCD systems. The drum filter has a cylindrical drum equipped with filter cloth, which is used to filter the slurry, dehydrate it into cake, wash it and unload the filter cake. According to the installation position of the filter cloth, it can be divided into external filter type and internal filter type. The internal filter type drum filter is suitable for slurry with good settling performance; the external filter type drum filter is divided into: scraper type, folding belt type and rope belt type according to the filter cake unloading method. In the uranium industry, it is mainly external filter type and scraper discharge.
(2) Disc filter. The disc filter is composed of multiple (up to 15) circular filter discs, each disc is composed of 8 to 30 cake-shaped discs.
The number of cake-shaped discs depends on the diameter of the filter, which is divided into two types: vertical disc type and horizontal disc type. At present, the maximum filtration area of ??the vertical disc machine reaches 200 m2. The vertical disc filter cake cannot be washed on the disc, and the filter cake can only be washed by dilution washing: the horizontal disc filter occupies a relatively large area.
(3) Horizontal tape vacuum filter. It is mainly composed of two driving rollers separated by a certain distance, a driven roller or a tensioning roller, and a jointless annular rubber belt. The filter belt slides on the vacuum suction box with a maximum speed of 15 cm/s. The filter belt is covered with filter cloth, and the slurry is added to the filter cloth to achieve solid-liquid separation under the action of vacuum suction. This kind of belt filter has a large processing capacity per unit area and can perform multiple stages of washing on one machine. The maximum filtration area of ??foreign equipment has reached 200 m2.
(4) Filter press. Filter presses are mainly used for dehydration of chemical products with high viscosity and fine particles, dehydration of concentrates in mineral processing plants, gold cyanide washing and other operations. They are rarely used in tailings treatment. However, the high-efficiency multi-frequency filter press developed by Yantai Xinhai Mining Machinery Dewatering screens have many unique technologies in design and are widely used in tailings dry discharge with high dehydration efficiency. However, due to its good dehydration effect, strong adaptability, and flexible processing methods of tailings after filter press dehydration, it has been widely used in the treatment of gold mine tailings, and has also been reported in the treatment of metallurgical mine tailings. The application of filter press in gold cyanide tailings also has some special significance. Theory and practice have proven that there is a dehydration limit for mechanical methods to remove external moisture from fine-grained materials, especially the agglomeration problem of ultra-fine powder materials. Therefore, production technology often requires thermal drying and dehydration separation operations after mechanical filtration and separation. . Thermal drying is an operation that uses thermal energy to convert the moisture in the material from the liquid phase into the vapor phase for separation. It can achieve deep solid-liquid separation based on mechanical filtration and separation. Generally, a fluidized drying method is used or a depolymerization device is installed in the drying equipment or after drying.