Method for improving purity of finished salt of evaporation-process salt and nitrate co-production process

Abstract

The invention discloses a method for improving the purity of finished salt of an evaporation method co-production salt nitrate process, wherein the method at least comprises the following three steps:S1, separating solid-liquid mixed phase high-concentration salt slurry obtained by evaporative crystallization in an evaporative crystallization tank to obtain solid-phase salt crystals and salt liquid; S2, mixing the salt crystals obtained in the step 1 with salt-making refined brine required by evaporative crystallization to prepare turbid liquid containing a large amount of salt crystals; S3,concentrating, purifying, separating and drying the turbid liquid obtained in the step 2, obtaining purified high-purity salt crystals, and mixing the solution generated by separation into salt-makingrefined brine to be used as raw brine for salt-nitrate co-production. The method is based on an existing evaporation method for salt-nitrate co-production; the method has the advantages of no influence on the balance of the original brine and a water system, no obvious increase of the thermal load of the system, realization of the breakthrough improvement of the purity of the finished salt to 99.9% by separating, elutriating and purifying the high-concentration solid-liquid mixed phase salt slurry obtained through evaporative crystallization in the evaporative crystallization tank, simplicity, and obvious economic benefits.

Description

technical field [0001] The invention relates to the technical field of thermal salt and nitrate co-production technology, in particular to a method for improving the purity of finished salt in the evaporation co-production of salt and nitrate. Background technique [0002] At higher than normal temperature, NaCl-Na 2 SO 4 -H 2 O brine system shows that the solubility of NaCl increases with the increase of temperature, and the solubility of NaCl 2 SO 4 Solubility tends to decrease with the increase of temperature. Based on this characteristic, domestic mineral salt basically adopts the process of co-production of salt and nitrate by evaporation method to produce salt and nitrate (see figure 1 ). [0003] refer to figure 1 , the prior art evaporation co-production salt salt system uses the refined brine to pass through the condensed water, the secondary steam preheats and then feeds downstream, 201 to 304 evaporates the salt, advectively discharges the salt with the refi...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that the prior art cannot further purify the purity of the finished salt, and propose a method for improving the purity of the finished salt of the evaporation co-production salt nitrate process

Images