Method of improving hardness of granular sodium nitrate

Abstract

The invention relates to a method of improving the hardness of granular sodium nitrate. According to the method, a waste salt is added by using a hopper and a screw conveyer in the process of conveying the wet sodium nitrate which is obtained by crystallizing through evaporation to a melting tank, wherein the waste salt contains 60-90% by weight of sodium chloride or 10-40% by weight of sodium sulfate. Due to the addition of 0.01-2.5% of the waste salt which contains sodium chloride or sodium sulfate, the hardness of the granular sodium nitrate can be up to 2-4kgf, and the granular sodium nitrate with a size of 2-4mm accounts for more than 96%. Due to the added waste salt which is rich in sodium chloride, the hardness of the granular sodium nitrate can be improved. By adopting the method provided by the invention, the granular sodium nitrate which has a lower content of water, higher roundness and more uniform size than the existing granules can be obtained. In addition, the method can realize continuous production, consumes less energy, is high in efficiency and low in cost and can be particularly applied to the field of tower-based chemical granulation.

Description

technical field [0001] The invention relates to a compound preparation technology of IPC international patent classification C01D alkali metal sodium, especially a method for improving the hardness of granular sodium nitrate. Background technique [0002] Nitrate minerals are generally white, colorless, light gray, vitreous luster, transparent to translucent, often in needle-like, hair-like, granular, shell-like, salt bloom-like aggregates, low density, brittle , soluble in water, low hardness. In the industrial grade sodium nitrate standard GB / t 4553-2002, there is a clear requirement for the appearance to be white fine crystals, and light yellow or light gray is allowed. Industrial-grade sodium nitrate is an oxidizing agent with a hazard category of 5.1, which has stricter requirements during transportation. According to international safety transportation requirements, industrial-grade sodium nitrate products must be granular, and the dust content must be strictly contr...

AI Technical Summary

Problems solved by technology

[0006] Usually, after granulation, the sodium nitrate product has a particle strength of 0.5-2kgf, a particle size of 2-4mm, and a particle content of 60-90%. The empty shell rate is high, and it is unstable during the handling process, which may easily cause a large amount of powder.