Conical-Cylindrical Vacuum Mixer-Dryer
With the rapid development of the lithium-ion battery industry, currently commercialized lithium cobaltate materials have been facing the trend of being gradually replaced by ternary materials due to high cost, low specific capacity, and high toxicity. The layered ternary material lithium nickel cobalt manganate has a synergistic effect due to the combination of the advantages of lithium manganate, lithium cobaltate and lithium nickelate, and has become one of the lithium ion cathode materials with good application prospects; Among the ternary materials, high nickel ternary materials have the advantages of higher nickel content, high discharge capacity, low cost, and low pollution.
The mainstream technological processes of ternary material precursors are: synthesis, filtration, washing, drying, and ternary material compounding, sintering, crushing, iron removal and other processes. Shuangrui Machinery analyzes the advantages and disadvantages of existing multiple filtration and washing equipment , In order to meet the requirements of high quality and high efficiency in the production process of ternary material precursors, we finally developed a multi-functional barrel-cone two-in-one device that integrates filtration and washing. It also has reaction, extraction, crystallization, concentration, and drying. , Mixing, crushing and other functions to meet the needs of the industry of ternary materials and precursors towards the development of intelligence, large capacity, low energy consumption and environmental friendliness.
The role of the filtration and washing equipment is to achieve solid-liquid separation of the precursor slurry obtained by the reaction, and then use the washing liquid to wash the obtained precursor filter cake to remove sulfate, chloride, sodium ions, etc. remaining in the filter cake . At present, most precursor manufacturers use integrated filtering and washing equipment, mainly including filter presses, centrifuges, microporous filters, and "two-in-one" filtering and washing equipment.
1. Filter Press
Filter press is a commonly used filtering and washing equipment. The traditional filter press generally requires manual operation of the entire filter press process, including feeding, pressing, air blowing, and unloading, especially the labor intensity of unloading is large, the filter cake is difficult to take off, the entire filter press cycle is long, the processing volume is small, dehydration and The washing effect is poor, and the material is usually cast iron, which is heavy and easy to wear. In recent years, the technical level of the filter press has been greatly improved, and the automatic filter press has been well applied. The entire filter press process is automatically controlled. The material is stainless steel or synthetic materials, and the filter room and structure are enlarged. Diaphragm design, and increased filtration pressure, large processing capacity, short filtration cycle, high dehydration efficiency, good washing effect, can meet the production requirements of ternary precursors.
A centrifuge is a machine that uses centrifugal force to separate liquid and solid particles or different components in a liquid mixture. The core component of the centrifuge is a rotating drum, a cylinder rotating at high speed around its own axis, usually driven by a motor. After the solid-liquid mixture enters the rotating drum, it is quickly driven to rotate at the same speed as the rotating drum, and the solid and liquid are separated under the action of centrifugal force. The solid particles are intercepted on the inner wall of the rotating drum and the liquid is discharged from the centrifuge. Commonly used centrifuge types are three-legged centrifuges, flat-plate centrifuges, horizontal spiral centrifuges, disc separators, and tube separators, among which three-legged centrifuges and flat-plate centrifuges are suitable for ternary precursors produce.
In the production, the flat-plate automatic lower discharge centrifuge is used to filter and wash the nickel and cobalt ultrafine powder materials. Each batch can process about 240kg of nickel cobalt ultrafine powder material filter cake. After washing 6 times, the product In Na<0.01%, SO2<0.4%, Cl<0.05%, it can meet the washing process requirements, and the metal recovery rate is above 99.7%, and the production efficiency is high.
3. Microporous filter
Microporous filter is a new type of solid-liquid separation equipment, which has the characteristics of high operating efficiency and high filtration accuracy. The structure of the microporous filter is to suspend special polymer PE and PA microporous tubes in the vertical sealed body, and the filtrate is discharged through the microporous tubes.
In recent years, the filtration and washing processes in the production of ultrafine powder have been well applied. In the production, the microporous filter is used to filter and wash the ultrafine cobalt carbonate powder with small particle size and high viscosity. The final consumption of washing water is 4.0t/h, which can make the Na content less than 0.005%, and the metal recovery rate Above 99.7%, the content of metallic cobalt in the mother liquor is 20 mg/L, and the water content of the filter cake is about 20%.
4. Filter and wash the "two-in-one" equipment (Agitated Nutsche Filter and Dryer)
The "two-in-one" equipment for filtration and washing is a simplified product based on the "three-in-one" equipment for filtration, washing and drying. The two processes of filtration and washing are completed in a closed container. It is mainly used in the pharmaceutical industry to solve The continuous production of flammable, explosive and toxic products is particularly suitable for materials with high washing effect requirements, and can reduce the labor intensity of the operation process and reduce the loss of finished products. The device has been used in the production of ternary precursors in recent years.
Cone-type filter washing equipment for ternary material precursor
The existing filtering and washing "two-in-one" structure is a flat plate type, but some defects have been found in long-term production and use, such as: the bottom of the flat plate has a small filtering area; the side discharge, resulting in incomplete discharge; the filtration effect is not ideal, During the filtration process, the material is turned little and the efficiency is low.
In order to overcome the problems and deficiencies in the above unit equipment combination, and at the same time meet the requirements of high quality and high efficiency of the ternary material precursor production process, our company conducted a lot of design and development work, and finally successfully developed a combination of filtration and washing. Conical-Cylindrical Vacuum Mixer-Dryer has the main functions of filtration and washing, and also has multiple functions of reaction, extraction, crystallization, concentration, drying, mixing, crushing, etc. It belongs to the improved mufti-function equipment.
Conical-Cylindrical Vacuum Mixer-Dryer Working Process
1. Press filter or vacuum filter
Open the lower filtrate outlet, pass compressed air or nitrogen gas into the equipment, and pressurize and filter the solid-liquid mixture after the reaction until the materials in the machine are pressed dry. You can also evacuate the filtrate outlet to vacuum filter the material until the filtrate is dried. When filtering, the hollow shaft and the hollow spiral belt can be rotated clockwise (looking down from the top) to lift the material, and the hollow spiral belt can limit the thickness of the filter cake layer when rotating, so that the material is in a thin filter cake Filtration under layer conditions to increase the filtration rate. For materials that can be easily filtered, the materials can be directly filtered without stirring.
2. Can be washed and filtered multiple times
After filtering some materials, it is necessary to wash several times. The reaction filtration and drying multifunctional machine is an ideal equipment for repeated washing of materials many times. After the material is pressed dry in the machine, the washing liquid can be added at the inlet of the top washing liquid, and then the filter cake is evenly re-slurried by the stirring of the hollow shaft and the hollow spiral belt, and the material is pressed and dried after being evenly stirred. If washing once is not enough, it can be washed multiple times, then repeat the above steps many times, the operation is very convenient, and the labor intensity is extremely low.
Washing the materials in the above method is called intermittent washing. Because each time the material is pressed to dry, the washing liquid is added for washing. Therefore, although the valve is opened and closed more times during operation, less washing liquid is used. The machine can also continuously wash the materials, that is, the washing liquid is continuously pressed in by a pump or other methods, and the pressure of the washing liquid is used for filtration. The hollow shaft and hollow spiral belt are continuously stirred, and the filtrate is continuously discharged from the filtrate outlet until Until the washing requirement is reached, the filter cake is finally pressed dry. This method of continuous washing is generally more than the amount of washing liquid used for intermittent washing, but the operation is more convenient.
Keywords: high nickel ternary material filter washing, ternary precursor preparation method, cone-cone filter washing equipment, Conical-Cylindrical Vacuum Mixer-Dryer
Wuxi Shuangrui Machinery Co., Ltd. analyzed the advantages and disadvantages of various existing filtration and washing equipment, and successfully developed Conical-Cylindrical Vacuum Mixer-Dryer . It also has reaction, extraction, crystallization, concentration, and drying. , Mixing, crushing and other functions to meet the needs of the industry of ternary materials and precursors towards the development of intelligence, large capacity, low energy consumption and environmental friendliness.