CN105836764A

CN105836764A - Recycling method of waste salt from salt-containing waste water in organic synthetic industry

Info

Publication number: CN105836764A
Application number: CN201610174088.8A
Authority: CN
Inventors: 王连军; 周解臻; 于婷婷; 沈辰阳; 韩卫清; 孙秀云; 李健生; 沈锦优
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2016-03-24
Filing date: 2016-03-24
Publication date: 2016-08-10
Anticipated expiration: 2036-03-24
Also published as: CN105836764B

Abstract

The invention discloses a recycling method of waste salt from salt-containing waste water in organic synthetic industry. The recycling method includes the steps of: evaporating the salt-containing waste water in the organic synthetic industry to obtain salt residue containing sodium chloride and sodium dihydrogen phosphate; eluting the salt residue and performing solid-liquid separation, preparing a saturated water solution of the salt residue at 80-90 DEG C from the separated solid, wherein residual undissolved salt residue is recycled and is repeatedly dissolved for more than 5 times to prepare sodium chloride; and cooling the saturated solution to 2-5 DEG C to crystallize the saturated solution to separate sodium dihydrogen phosphate. The industrial waste salt as the raw material is turned from waste into resources, so that the method is beneficial to environment protection and comprehensive utilization. The recycled sodium chloride and sodium dihydrogen phosphate are high in quality and has good crystal granularity. The method reaches more than 80% in recycling rate and more than 98% in product purity.

Description

The recovery method of abraum salt in a kind of organic synthesis industry brine waste

Technical field

The invention belongs to energy-conserving and emission-cutting technology field, be specifically related to the recovery side of abraum salt in organic synthesis industry brine waste Method.

Background technology

Sodium dihydrogen phosphate is a kind of important chemical products, has extensively use at aspects such as medicine, food, chemical industry, agriculturals On the way.Industry Waste sodium chloride is that a kind of yield is big and intractable pollutant, and general processing method is dilution discharge, but meeting Cause serious land pollution.Document 1 uses cool technology-floatation process that halide salt carries out separating-purifying, but the party The product quality that method obtains is the highest, and the response rate of halide salt is not ideal enough, and only 40%～50%, and many in technological process Control that individual link such as ore deposit is measured, the misoperation decomposed in the control of the water yield, the interpolation of floating agent and washing etc. all can be made Become the best impact of product recovery rate (Zhang Yikui, potassium chloride and the experimental study of sodium chloride separating technology in carnallite, Sea lake salt and chemical industry, 1994).Zheng Xueming et al. uses phosphoric acid and the reaction of Industry Waste sodium chloride to produce sodium dihydrogen phosphate, Although can solve the problem that the pollution problem of industrial chlorinations sodium, and produce sodium dihydrogen phosphate, but technique needs to add additionally Concentrated acid realize, to installations and facilities require higher, technological process is complex, deals with improperly and can cause bigger to environment Pollution (Zheng Xueming, industrial waste salt produce sodium dihydrogen phosphate technical study, the 26th Annual Conference of Chemistry In China is green Colour chemistry collection of thesis, 2008).Therefore, find a kind of efficient recovery and process the saliferous waste residue in organic industry synthetic wastewater Environmental conservation and comprehensive utilization of waste materials had highly important practical significance.

Summary of the invention

For the deficiencies in the prior art, the invention provides the recovery side of abraum salt in a kind of organic synthesis industry brine waste Method, can efficiently separate sodium chloride and sodium dihydrogen phosphate.

Technical scheme is as follows:

In a kind of organic synthesis industry brine waste, the recovery method of abraum salt, specifically comprises the following steps that

Step 1, the salt slag containing sodium chloride and sodium dihydrogen phosphate that organic synthesis industry brine waste evaporation process is obtained Solid-liquid separation after processing with organic solvent eluting, the solid being dried to obtain；

Step 2, by salt slag dried in step 1 at 80 DEG C～90 DEG C soluble in water, obtain sodium chloride and di(2-ethylhexyl)phosphate The mixing saturated solution of hydrogen sodium, filters saturated solution and separates, and undissolved solid the most individually reclaims and repeats to dissolve, Repeat to dissolve at least 5 times, repeat undissolved solid in the saturated solution after dissolving and be sodium chloride；

Step 3, is cooled to 2 DEG C～5 DEG C by the saturated solution filtering isolated in step 2, stands more than 2h, waits to satisfy After separating out completely with the salinity in solution, solid separated, be dried, obtain sodium dihydrogen phosphate, after the evaporation of remaining liquid The salt slag obtained continues to repeat step 2 and step 3.

Preferably, in step 1, described organic solvent is ethanol or chloroform.

Compared with prior art, the present invention, with industrial waste salt slag as raw material, turns waste into wealth, beneficially environmental protection and comprehensive utilization, Process costs is low, reclaims the product quality that obtains high, and product crystalline substance position can reach more than 90%, reclaim obtain sodium chloride, Sodium dihydrogen phosphate grain size is preferable, and the response rate can reach more than 80%, and product purity is up to more than 98%.

Accompanying drawing explanation

Fig. 1 is the process chart of the present invention.

Detailed description of the invention

Below in conjunction with embodiment and accompanying drawing, the invention will be further described.

In conjunction with Fig. 1, in a kind of organic synthesis industry brine waste, the recovery method of abraum salt, specifically comprises the following steps that

Step 1, the salt slag containing sodium chloride and sodium dihydrogen phosphate that organic synthesis industry brine waste evaporation process is obtained Solid-liquid separation after processing with organic solvent eluting, and the solid of dry isolated；

Step 2, by salt slag dried in step 1 at 80 DEG C～90 DEG C soluble in water, obtain sodium chloride and di(2-ethylhexyl)phosphate The mixing saturated solution of hydrogen sodium, filters saturated solution and separates, and undissolved solid the most individually reclaims redissolution of laying equal stress on and solves, Repeat to dissolve at least 5 times, repeat undissolved solid in the saturated solution after dissolving and be sodium chloride；

Preferably, in step 1, described organic solvent is ethanol or chloroform.

Embodiment 1

Step 1, the waste salt dregs chloroform of the 500g that organic synthesis industry brine waste evaporation process obtains is by residual organic matter Carrying out eluting process, carry out solid-liquid separation subsequently, the solid after separating is dried in an oven at 90 DEG C.

Step 2, is dissolved in the water the salt slag after step 1 dried under conditions of 90 DEG C and prepares saturated salt solution, Individually reclaim redissolution of laying equal stress on after separating not having the solid dissolved to filter to solve, after at least 5 times are repeated to dissolve, in solution The solid dissolved is not had to be sodium chloride.

Step 3, is cooled to 2 DEG C by the saturated salt solution filtering separation in step 2, stands 2h, treats in saturated salt solution After salinity separates out completely, solid separated, be dried, obtain sodium dihydrogen phosphate, the salt slag obtained after unnecessary liquid evaporation Continue to repeat step 2 and step 3.

After repeating step 2～step 3 five times, the response rate is 87.4%, and the purity of sodium chloride and sodium dihydrogen phosphate is respectively It is 99% and 98%.

Embodiment 2

Step 1, residual organic matter is carried out eluting by the waste salt dregs ethanol of the 500g that organic synthesis waste water evaporation process obtains Processing, carry out solid-liquid separation subsequently, the solid after separating is dried in an oven at 90 DEG C.

Step 2, is dissolved in the water the salt slag after dried under conditions of 80 DEG C and prepares saturated salt solution, will not have The solid dissolved filters after individually reclaiming after separating and repeats to dissolve, and after at least 5 times process, does not dissolve in solution Solid is sodium chloride.

Step 3, is cooled to 5 DEG C by the saturated salt solution obtained in step 2, stands 2h, treats salinity in saturated salt solution After separating out completely, being separated by solid, be dried, just obtain sodium dihydrogen phosphate, the salt slag obtained after unnecessary liquid evaporation continues Continuous repetition step 2.

After repeating step 2～step 3 five times, the response rate is 80.2%.The purity of sodium chloride and sodium dihydrogen phosphate is 98%.

Claims

1. the recovery method of abraum salt in an organic synthesis industry brine waste, it is characterised in that specifically comprise the following steps that

The recovery method of abraum salt in a kind of organic synthesis industry brine waste the most according to claim 1, its feature exists In, in step 1, described organic solvent is ethanol or chloroform.