Method for purifying and producing low-cost environmental-protection level

Abstract

The invention discloses a method for purifying and producing low-cost environmental-protection level. The method comprises the following steps: 1, putting sodium salicylate raw material into a closedcontainer, adding pure water, stirring and soaking, performing dehydrating treatment after soaking completely, and dissolving with pure water; 2, after dissolving completely, adding ethylenediamine tetraacetic acid into the solution, continuously stirring and performing heat-preserving precipitation; 3, after heat-preserving precipitation, filtering the solution, concentrating and performing cooling crystallization; and 4, after complete crystallization, performing dehydrating treatment to obtain a primary crystal, and performing crystal baking treatment on the primary crystal to finally obtain the product. The primary purification effect is improved and the recrystallization times are reduced by a mode of removing impurities by chelates and removing impurities by an aqueous solution, so that under the condition that the product meets the environmental protection level requirement, the production cost of enterprises is greatly reduced, the profit space of the enterprises is increased and the defects in an existing production method are solved.

Description

technical field [0001] The invention relates to the technical field of sodium salicylate purification, in particular to a method for the purification and production of low-cost environment-friendly grade sodium salicylate. Background technique [0002] Sodium salicylate is a white scale or powder, soluble in water, glycerin, insoluble in ether, chloroform, benzene, mainly used for analgesics and rheumatism, also used as organic synthesis and analysis reagents, general sodium salicylate The preparation is: cross-add salicylic acid and sodium bicarbonate into distilled water, keep the temperature at 60°C, and keep it in an acidic state, and add appropriate amount of ethylenediaminetetraacetic acid (EDTA) and sodium bicarbonate at the same time. Raise the temperature to 85°C and react for half an hour. The qualified reaction solution is filtered and sent to the ebullating bed, and dried at 85°C to obtain sodium salicylate. [0003] At present, high-purity environmentally frie...

AI Technical Summary

Problems solved by technology

This method replaces pure water with ethanol, and adsorbs precipitated particles with activated carbon. Although ethanol can be recycled, it has the following disadvantages: 1. The amount of ethanol used is large and energy consumption is large. Generally, 50 kg of sodium salicylate is used in industry The raw material is produced in one batch, and each batch needs to use 270L of 95wt% ethanol, which requires a large amount of use, and the energy consumption of water bath and distillation recovery in the later stage is large, and the ethanol itself is highly volatile, and the loss of ethanol in the production process is large, and its production cost is obviously high Recrystallization and refining in aqueous solution; 2. The mother liquor contains a lot of impurities, and repeated use will affect the purity. When ethanol is used as a solvent, some organic impurities and heavy metals will also dissolve in the mother liquor. These impurities are trace amounts, which cannot be removed by activated carbon adsorption. After the mother liquor is reused, the content of these impurities accumulates. When the crystallization is concentrated and crystallized in the later stage, these impurities will be entrained in the crystallization, resulting in an increase in the content of crystallized impurities. It is foreseeable that the purity of the final product will not meet the standard.

Therefore, this purification method can not be used to solve the problem of low-cost production of high-purity environmental protection grade sodium salicylate in enterprises

Images