What are the principles and advantages of spray drying technology in the preparation of lithium ion battery materials?

Spray drying is to have a combination of granulation and drying of two kinds of process technology, through continuous operation can control the properties of the powder remained stable. Spray drying technology has been 100 years of history, in the industrial application of also has the nearly hundred years of history, started only a few product such as egg powder, milk powder, detergent production, with the deepening of research, is now in a variety of industrial ultrafine powder and nano powder is widely used in production. Quality can be produced from the spray drying technology can uniform spherical powder, good repeatability, shorten the preparation process of powder, and conducive to automated, continuous production, and is an effective method of large scale preparation of fine powder, superfine refinement has become a variety of products and drying is one of the best practices.

1. The basic principle and characteristics of spray drying method

Common sprayer has three types: pressure sprayer, air-blast atomizer, centrifugal atomizer. Pressure sprayer used more, so in this paper, the spray drying technology for explanation.Spray drying technology for superfine powder material from the material liquid of a good method, can be in the form of material liquid solution, suspension, emulsion pump can transport liquid.Its basic principle is to use the atomizer to a certain concentration of slurry injection into fog droplets that fall into a certain flow rate of heat flow, quick drying, powder products.

Specific process of spray drying method for (shown in figure 2) : heater to produce heat (thermal drying medium) by the hot air duct into the tower from the top of the drying tower, at the same time, sample sent of material liquid through atomizing nozzle jet pump into extremely thin spherical droplets, in a certain flow rate of heat flow in heat transfer, due to droplets are subtle, specific surface area is large, fast solvent evaporation, drying and granulating process completed in an instant. After drying under the finished product from the tower body of conical discharging mouth into the cyclone separator, and the drying medium separation after collected in receiver products, hot waste gas by induced draft fan by the vent discharge.

Spray drying generally include four stages: (1) material liquid atomization;(2) fog group of contact with the hot drying medium mixed;(3) droplets evaporation drying;(4) drying products and drying medium separation. Dry products can be powder, granular or particles aggregate.

Compared with other powder preparation, spray drying method has the following advantages:

(1) Can make granulation, drying, spray drying step is completed, the production process is simple, convenient operation and control, new chemical industry production, easy to realize automation.

(2) The drying rate is high, the time is short, smaller influence on heat sensitive components, and especially suitable for drying of thermal sensitive material.

(3) Spray drying, the material liquid is stirring constantly in a state of spray atomization dispersions, instantaneous drying, so has good uniformity.

(4) In spray drying, because the solvent gasification rapidly finished tiny particles for osteoporosis, when in contact with the solvent, solvent into the particle internal easily, without further processing can also achieve good dispersion and good solubility.

(5) Due to the spray drying is a kind of closed continuous production, make the product high purity, put an end to the exposure, and contact with the operator in the production environment, reducing the pollution of the environment.

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