Method for producing sodium chlorate through low-temperature vacuum evaporation and crystallization

Abstract

The invention relates to a method for producing sodium chlorate through low-temperature vacuum evaporation and crystallization, belonging to the field of chlor-alkali chemical industry and solving the technical problem of providing the method for producing the sodium chlorate with lower production cost. The method for producing the sodium chlorate comprises a steps of crystallizing and separating sodium chlorate from sodium chlorate electrolyte. A method crystallizing and separating the sodium chlorate from the sodium chlorate electrolyte comprises the following steps of: a, mixing the sodium chlorate electrolyte with a right amount of mother solution to obtain a mixed solution with the density of 1.30-1.40 g / cm<3>, heating in vacuum, and boiling the mixed solution at 35-45 DEG C, wherein the mother solution is a solution remained after the sodium chlorate is crystallized, precipitated and separated from the sodium chlorate electrolyte, the concentration of NaCl contained in the mother solution is less than or equal to 130 g / L; b, stopping heating when the density of the mixed solution is 1.50-1.60 g / cm<3>; and c, discharging, cooling, filtering, washing and drying to obtain the sodium chlorate.

Description

technical field [0001] The invention relates to a method for producing sodium chlorate by low-temperature vacuum evaporation and crystallization, which belongs to the field of chlor-alkali chemical industry. Background technique [0002] At present, the production of sodium chlorate mainly adopts electrolysis of refined brine, and then crystallization and separation to obtain sodium chlorate. Sodium chlorate is generated after the refined brine is electrolyzed by a diaphragmless ruthenium-iridium-titanium metal anode electrolyzer, and the solution formed by sodium chlorate, sodium chloride and water is called electrolysis completion solution (also known as sodium chlorate electrolyte). The sodium chlorate electrolyte is mixed with an appropriate amount of mother liquor (the mother liquor is the solution left after the crystallization of the sodium chlorate electrolyte and separation of sodium chlorate, containing sodium chlorate crystal seeds, which is beneficial to the form...

AI Technical Summary

Problems solved by technology

[0007] 1. Its process route is long, including evaporator, crystallizer, crystallization and separation equipment, steam transportation, boiler, etc.;

[0008] 2. High investment and long construction time;

[0009] 3. The scale of the single sodium chlorate production line is small, with an annual output of only 5,000-10,000 tons, and the scale benefit is poor;

[0010] 4. The energy consumption is relatively high. The energy types are mainly electric energy and steam (coal). The annual total energy consumption reaches 325 million degrees (6500 degrees per ton of electricity consumption). In addition, a high-temperature evaporation process is adopted, and steam must be used. The coal boiler Heating steam supply, consuming 3.5 tons of steam per ton of sodium chlorate;

[0011] 5. Due to the use of coal boilers, there are always many difficulties in environmental protection, and the environmental protection department has strict requirements on the project