阅读说明：本技术 一种四溴双酚a生产所得硫酸钠废盐的处理方法 (Treatment method of sodium sulfate waste salt obtained in tetrabromobisphenol A production ) 是由 刘朝晖 张研 刘红雨 周清云 王春玲 王宇斌 于 2021-06-23 设计创作，主要内容包括：本发明提供了一种四溴双酚A生产所得硫酸钠废盐的处理方法,将四溴双酚生产过程中所得到的硫酸钠废盐进行充分粉碎,将盐颗粒进行两级烘干,将有机物转化为无机碳,同时通过四溴双酚A的生产控制,实现烘烤尾气基本不含溴类物质,烘烤后的盐经过蒸发、过滤、离心、烘干等操作过程后,得到可销售的硫酸钠固体产品。本发明提供的分解处理的方法,可以将现有的的硫酸钠工业废盐转化为产品级硫酸钠用于销售,既可以有效缓解工业废盐的库存压力,又可以实现“变废为宝”。去除盐分中的有机物作为产品对外销售,产生的废水废气及废渣均可能够实现达标排放,达到了连续化生产四溴双酚A的要求,进一步促进实现企业效益最大化。(The invention provides a method for treating sodium sulfate waste salt obtained in the production of tetrabromobisphenol A, which comprises the steps of fully crushing the sodium sulfate waste salt obtained in the production process of tetrabromobisphenol, drying salt particles in two stages, converting organic matters into inorganic carbon, realizing that baking tail gas does not contain bromine substances basically through the production control of tetrabromobisphenol A, and obtaining a marketable sodium sulfate solid product after the baked salt is subjected to the operation processes of evaporation, filtration, centrifugation, drying and the like. The decomposition treatment method provided by the invention can convert the existing industrial waste salt of sodium sulfate into product-grade sodium sulfate for sale, thereby not only effectively relieving the inventory pressure of the industrial waste salt, but also realizing the purpose of changing waste into valuable. Organic matters in the removed salt are sold as products, the produced waste water, waste gas and waste residues can be discharged up to the standard, the requirement of continuously producing tetrabromobisphenol A is met, and the maximization of enterprise benefit is further promoted to be realized.)

1. A treatment method of sodium sulfate waste salt obtained in tetrabromobisphenol A production is characterized in that: the method comprises the following steps:

1) crushing the raw materials in a closed environment;

2) drying and baking the crushed sodium sulfate waste salt for two-stage treatment process, wherein the first-stage drying is drying for 0.5-1.5 h at the temperature of 80-110 ℃, the second-stage baking is baking for 2-3 h at the temperature of 400-500 ℃, the dried water vapor is recycled for subsequent dissolving tank water through a condensing system, and tail gas generated in the baking process enters a tail gas recycling system;

3) cooling the baked salt to prepare a 25% aqueous solution, obtaining a clear sodium sulfate aqueous solution through a two-stage filtration system, and transferring the filtered solid impurities to a solid waste center for harmless treatment;

4) and (3) carrying out vacuum evaporation and concentration on the filtered mother liquor to obtain a relatively pure anhydrous sodium sulfate product, carrying out centrifugal drying to obtain a sodium sulfate solid, and using steam condensate water in the evaporation process, exhaust water in the evaporation process and the centrifugal mother liquor for dissolving and mechanically applying in subsequent batches.

2. The method for treating waste sodium sulfate salt produced in tetrabromobisphenol A production according to claim 1, wherein: in the step 1), crushing the raw materials into raw salt particles with the diameter of 0.5-1 cm by a crusher at room temperature in a closed environment.

3. The method for treating waste sodium sulfate salt produced in tetrabromobisphenol A production according to claim 1, wherein: in the step 2), the primary drying temperature is controlled at 100 ℃, the secondary baking temperature is controlled at 500 ℃, the primary drying time is one hour, and the secondary baking time is two hours.

4. The method for treating waste sodium sulfate salt produced in tetrabromobisphenol A production according to claim 1, wherein in step 3), the baked salt is cooled and then enters a salt dissolving tank to prepare an aqueous solution, the dissolving temperature is 45-60 ℃, the stirring speed is controlled at 80-100 r/min, and the pH value is controlled at 8-9.

5. The method for treating waste sodium sulfate salt produced in tetrabromobisphenol A production according to claim 1, wherein: in the step 3), the filtering aperture of the first-stage filtering system is controlled to be 100 micrometers, and the filtering aperture of the second-stage filtering system is controlled to be 10 micrometers.

6. The method for treating waste sodium sulfate salt produced in tetrabromobisphenol A production according to claim 1, wherein: in the step 4), the steam temperature is 125-142 ℃, and the vacuum degree is 0.03-0.06 MPa.

Technical Field

The invention relates to the technical field of waste salt treatment, in particular to a method for treating sodium sulfate waste salt obtained in tetrabromobisphenol A production.

Background

Domestic waste salt is widely concerned by society and the public due to the problems of high yield, high toxicity, difficult treatment and disposal and the like, in the industrial production of organic chemical industry, most of solid wastes of enterprises are mainly industrial sodium sulfate, the solid wastes are mainly sodium sulfate, the contained components are extremely complex, toxic and harmful substances are not lacked, and a plurality of enterprises adopt methods of warehouse stockpiling, open-air placement and the like, but the method treats the symptoms and causes no root cause, occupies a large amount of land, destroys soil, pollutes the environment and threatens the living environment, physical and mental health of people around.

At present, the main techniques of the domestic physical and chemical method for treating the waste sodium sulfate salt comprise a recrystallization method, an advanced oxidation method, a landfill and sea drainage method and the like.

(1) And (3) recrystallizing, wherein sodium sulfate is dissolved in a solvent by utilizing the solubility difference of solutes, and crystals are crystallized and separated out from the solution again by cooling, spraying and other operations. The method has low technical difficulty, easy operation and low yield, and needs multiple times of dissolution and recrystallization, thereby leading the investment cost to be higher, basically not being capable of removing organic matters contained in salt, having no obvious effect on the color control of the salt, and having larger water consumption for recrystallization.

(2) The advanced oxidation method is characterized in that on the basis of re-dissolving solid sodium sulfate, toxic and harmful organic pollutants are oxidized by means of the strong oxidizing property of a chemical oxidant, so that the waste salt is harmless, and clean byproduct salt is obtained. The treatment effect of the advanced oxidation method is often dependent on the properties of organic pollutants, and the method has an unobvious treatment effect on sodium sulfate wastewater containing tetrabromobisphenol A through practical verification and is not suitable for manufacturers of tetrabromobisphenol A.

(3) The method is characterized in that hazardous wastes such as saline water concentrate or solid waste salt and waste residue are used for landfill, the landfill treatment needs to occupy a large amount of fields, meanwhile, waste salt easily causes corrosion influence on an impermeable lining, the sea drainage is that salt-containing wastewater is directly drained in the offshore or collected waste salt is transported to the open sea for deep sea drainage, but before drainage, harmless treatment is needed, and pollution to the ecological environment is avoided, so that the method has great limitation.

For enterprises producing tetrabromobisphenol A, the organic substance components in the obtained industrial sodium sulfate waste salt are extremely complex, and most of the organic substances are bromine-containing organic substances, so that the treatment difficulty is further increased, and therefore, the bromine-containing substances are not contained basically in the tail gas component discharged in a controlled manner while the product-grade sodium sulfate is realized, and the process is an effective treatment process for the waste salt containing organic substances such as tetrabromobisphenol A and the like.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a method for treating sodium sulfate waste salt obtained in tetrabromobisphenol A production, which can convert the existing sodium sulfate industrial waste salt into product-grade sodium sulfate for sale, thereby not only effectively relieving the inventory pressure of the industrial waste salt, but also realizing the purpose of changing waste into valuable; the waste water, waste gas and waste residue produced can be discharged up to the standard, the requirement of continuously producing tetrabromobisphenol A is met, and the maximization of enterprise benefit is further promoted to be realized.

Based on the problems, the technical scheme provided by the invention is a method for treating sodium sulfate waste salt obtained in tetrabromobisphenol A production, which comprises the following steps:

1) crushing a weakly alkaline raw material in a closed environment;

2) drying and baking the crushed sodium sulfate waste salt for two-stage treatment process, wherein the first-stage drying is drying for 0.5-1.5 h at the temperature of 80-110 ℃, the second-stage baking is baking for 2-3 h at the temperature of 400-500 ℃, the dried water vapor is recycled for subsequent dissolving tank water through a condensing system, and tail gas generated in the baking process enters a tail gas recycling system;

3) cooling the baked salt to prepare a 25% aqueous solution, obtaining a clear sodium sulfate aqueous solution through a two-stage filtration system, and transferring the filtered solid impurities to a solid waste center for harmless treatment;

4) and (3) carrying out vacuum evaporation and concentration on the filtered mother liquor to obtain a relatively pure anhydrous sodium sulfate product, carrying out centrifugal drying to obtain a sodium sulfate solid, and using steam condensate water in the evaporation process, exhaust water in the evaporation process and the centrifugal mother liquor for dissolving and mechanically applying in subsequent batches.

The crushing process in the step 1) is to crush the raw materials into raw salt particles with the diameter of 0.5-1 cm by using a crusher in a closed environment at room temperature.

In the step 2), preferably, the primary drying temperature is controlled at 100 ℃, the secondary baking temperature is controlled at 500 ℃, the primary drying time is one hour, and the secondary baking time is two hours, so that the substances such as tetrabromobisphenol A and tribromophenol attached to the sodium sulfate and the sodium bromide can be converted into inorganic carbon and the bromine-containing substances are converted into sodium bromide under the condition that the sodium sulfate and the sodium bromide are not melted. The gas generated by baking basically does not contain bromine substances, and mainly takes combustible gases such as hydrogen, methane, carbon dioxide and the like as main materials, thereby reducing the difficulty of tail gas treatment.

And in the step 3), the baked salt is cooled and then enters a salt dissolving tank to prepare an aqueous solution, the dissolving temperature is 45-60 ℃, the stirring speed is controlled at 80-100 r/min, and the pH value is controlled at 8-9.

In the step 3), the filtering aperture of the first-stage filtering system is controlled to be 100 micrometers, and the filtering aperture of the second-stage filtering system is controlled to be 10 micrometers.

In the step 4), the steam temperature is 125-142 ℃, and the vacuum degree is 0.03-0.06 MPa.

The invention has the advantages and beneficial effects that:

the method fully crushes the sodium sulfate waste salt obtained in the production process of tetrabromobisphenol, dries salt particles in two stages, converts organic matters into inorganic carbon, realizes that the baking tail gas does not contain bromine substances basically through the production control of tetrabromobisphenol A, obtains a saleable sodium sulfate solid product after the baked salt is subjected to the operation processes of evaporation, filtration, centrifugation, drying and the like, and can effectively relieve the inventory pressure of industrial waste salt and realize the purpose of changing waste into valuable.

The waste gas mainly comprises hydrogen, methane and carbon dioxide, and meets the emission standard of industrial waste gas after tail gas treatment procedures such as incineration, denitration, catalytic oxidation adsorption, cloth bag dust removal and the like; the amount of the generated waste salt is very rare compared with the total amount of the original sodium sulfate waste salt, so that the waste salt is stored in a storehouse and is subsequently transferred to a solid waste center for treatment; the method comprises the steps of drying and baking the obtained water, steam condensate water in the evaporation process, steam-depleted water in the evaporation process and centrifugal mother liquor obtained through centrifugation, wherein other water except the steam condensate water is used for dissolving and mechanically applying, the steam condensate water is supplemented according to the water amount of water for sleeve application, and the water which is mechanically applied for many times enters a factory water treatment system for standard discharge, so that the requirement of continuously producing tetrabromobisphenol A is met, and the maximization of enterprise benefit is further promoted to be realized.

Detailed Description

The following examples are provided to illustrate specific embodiments of the present invention.

Example 1 a method for treating waste sodium sulfate salt from tetrabromobisphenol a production, comprising the steps of:

1) crushing a weakly alkaline raw material in a closed environment;

2) drying and baking the crushed sodium sulfate waste salt for two-stage treatment process, wherein the first-stage drying is drying for 1h at the temperature of 100 ℃, the second-stage baking is baking for 3h at the temperature of 500 ℃, the baked water vapor is recycled for subsequent dissolving tank water through a condensing system, and the tail gas generated in the baking process meets the emission standard of industrial waste gas and is discharged after reaching the standard after being subjected to tail gas treatment procedures such as burning, denitration, catalytic oxidation adsorption, cloth bag dust removal and the like;

3) cooling the baked salt to prepare an aqueous solution with the concentration of 25%, and then respectively obtaining a clear sodium sulfate aqueous solution through a first-stage filtering system with the filtering pore size of 100 micrometers and a second-stage filtering system with the filtering pore size of 10 micrometers; transferring the solid impurities obtained by filtering to a solid waste center for harmless treatment;

4) and (3) evaporating and concentrating the filtered mother liquor in vacuum to obtain a relatively pure anhydrous sodium sulfate product, wherein the steam temperature is 142 ℃, the vacuum degree is 0.06mpa, and centrifugally drying to obtain a sodium sulfate solid. The steam condensate water in the evaporation process, the exhaust water in the evaporation process and the centrifugal mother liquor are used for dissolving and mechanically applying in subsequent batches.

Embodiment 2 a method for treating waste sodium sulfate salt from tetrabromobisphenol a production, comprising the following steps:

1) crushing a weakly alkaline raw material in a closed environment;

2) drying and baking the crushed sodium sulfate waste salt for two-stage treatment process, wherein the first-stage drying is drying for 1h at the temperature of 100 ℃, the second-stage baking is baking for 3h at the temperature of 500 ℃, the baked water vapor is recycled for subsequent dissolving tank water through a condensing system, and the tail gas generated in the baking process meets the emission standard of industrial waste gas and is discharged after reaching the standard after being subjected to tail gas treatment procedures such as burning, denitration, catalytic oxidation adsorption, cloth bag dust removal and the like;

3) cooling the baked salt to prepare an aqueous solution with the concentration of 25%, and then respectively obtaining a clear sodium sulfate aqueous solution through a first-stage filtering system with the filtering pore size of 100 micrometers and a second-stage filtering system with the filtering pore size of 10 micrometers; transferring the solid impurities obtained by filtering to a solid waste center for harmless treatment;

4) and (3) evaporating and concentrating the filtered mother liquor in vacuum to obtain a relatively pure anhydrous sodium sulfate product, wherein the steam temperature is 142 ℃, the vacuum degree is 0.06mpa, and centrifugally drying to obtain a sodium sulfate solid. The steam condensate water in the evaporation process, the exhaust water in the evaporation process and the centrifugal mother liquor are used for dissolving and mechanically applying in subsequent batches.

Although the embodiments of the present invention have been described in detail, the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.