阅读说明：本技术 一种从工业副产石膏中回收硫的方法 (Method for recovering sulfur from industrial byproduct gypsum ) 是由 谭宏斌 马小玲 董发勤 杨飞华 李玉香 邓秋林 王进明 王进 王军霞 贺小春 李 于 2019-10-30 设计创作，主要内容包括：本专利公开了一种从工业副产石膏中回收硫的方法,在工业副产石膏中加入催化剂和还原剂,还原反应得到硫化钙；在硫化钙中加入水,水解反应得到氢氧化钙和硫氢化钙；在硫氢化钙溶液中通入二氧化碳气体,得到碳酸钙沉淀和硫化氢气体；对硫化氢气体进行吸收、氧化、液固分离,得到单质硫。同已有技术方案相比,本方法生产成本低,生产效率高,产品质量好的特点。(The patent discloses a method for recovering sulfur from industrial by-product gypsum, wherein a catalyst and a reducing agent are added into the industrial by-product gypsum, and calcium sulfide is obtained through reduction reaction; adding water into calcium sulfide, and performing hydrolysis reaction to obtain calcium hydroxide and calcium hydrosulfide; introducing carbon dioxide gas into the calcium hydrosulfide solution to obtain calcium carbonate precipitate and hydrogen sulfide gas; absorbing, oxidizing and carrying out liquid-solid separation on the hydrogen sulfide gas to obtain elemental sulfur. Compared with the prior art, the method has the characteristics of low production cost, high production efficiency and good product quality.)

1. The method for recovering sulfur from industrial by-product gypsum is characterized by sequentially comprising the following steps of: adding a catalyst and a reducing agent into the industrial byproduct gypsum, uniformly mixing, carrying out reduction reaction to obtain a reaction product, and sorting the reaction product to obtain calcium sulfide; adding water into calcium sulfide, performing hydrolysis reaction to obtain calcium hydroxide and calcium hydrosulfide, and performing liquid-solid separation to obtain calcium hydroxide solid and calcium hydrosulfide solution; introducing carbon dioxide gas into the calcium hydrosulfide solution to obtain calcium carbonate precipitate and hydrogen sulfide gas; adding a trapping agent and a pH regulator into a washer, and absorbing hydrogen sulfide gas to obtain a pregnant solution; and (3) introducing the absorbed rich solution into an oxidation tank, adding a surfactant and a foaming agent, introducing air into the oxidation tank, and separating the elemental sulfur generated by oxidation of the rich solution from the solution along with the upward floating of bubbles to obtain the elemental sulfur.

2. The method of claim 1, wherein the catalyst is one of hematite, waste battery anodes, chemical waste catalysts and electroplating residues, and the addition amount of the catalyst is 1-10% of the mass of the industrial byproduct gypsum.

3. The method of claim 1, wherein the reducing agent is one of waste plastics, waste rubber and waste engine oil, and the amount of the reducing agent added is 1-10% of the mass of the industrial by-product gypsum.

4. The method of claim 1, wherein the capture agent is one of manganese citrate, copper sulfate and iron lactate, and the addition amount is 0.1-5% of the mass of the industrial by-product gypsum.

5. The method of claim 1, wherein the pH regulator is one of calcium oxide, potassium carbonate and ammonium carbonate, and the amount of the pH regulator added is 0.1-5% of the mass of the industrial by-product gypsum.

6. The method of claim 1, wherein the surfactant is one of xanthate, ethionine and nigricans, and the amount of the surfactant added is 0.01 to 0.1% of the mass of the industrial by-product gypsum.

7. The method of claim 1, wherein the foaming agent is one of cresol glycerol ether, methyl isobutyl carbinol, methyl amyl alcohol and polyethylene glycol ether, and the addition amount of the foaming agent is 0.01-0.1% of the mass of the industrial by-product gypsum.

Technical Field

The invention relates to the field of resource utilization of industrial waste residues, in particular to utilization of industrial byproduct gypsum.

Background

Gypsum is a sulfate mineral with the chemical formula CaSO₄·xH₂And O. The gypsum is divided into natural gypsum and industrial by-product gypsum. At present, the industrial by-product gypsum mainly comprises phosphogypsum, desulfurized gypsum and titanium gypsum, and also comprises a small amount of fluorgypsum, citric acid gypsum, salt gypsum and the like.

Phosphogypsum is a by-product of wet-process phosphoric acid industry, and 1 ton of phosphate fertilizer (P) is produced₂O₅Calculated) yields about 4.5 to 5.0 tons of phosphogypsum. According to statistics, the discharge amount of phosphogypsum in China reaches 8000 million tons in 2014, and the stacking amount of the phosphogypsum in the past year is accumulated to exceed 3 hundred million tons. On a national scale, the comprehensive utilization rate of phosphogypsum in 2015 in China is only 30%. And the residual gypsum is stacked nearby, and enterprises spend a large amount of expenses for building a slag yard and operating and managing the slag yard each year. Phosphogypsum contains impurities such as undecomposed phosphorite, free phosphoric acid, fluoride and the like, and a large amount of stacking causes environmental problems and pollutes soil, atmosphere and water. How to properly handle and treat it is an important issue it faces.

The desulfurized gypsum is a byproduct generated by limestone-lime wet flue gas desulfurization of a thermal power plant, and the byproduct is mainly dihydrate gypsum; the discharge of the desulfurized gypsum to rivers, lakes and seas is forbidden in China. The desulfurized gypsum is treated by adopting a stockpiling mode, so that land occupation, environment influence, capital occupation, resource waste and economic and environmental effects of a power plant are influenced [ Wangxiefei, Liu Lun, Mapengjun, and the like. 42-45].

When titanium gypsum is used for producing titanium dioxide by adopting a sulfuric acid method, limestone and calcium oxide are added for treating acidic waste water to neutralize waste residue generated by the acidic waste water, the main components of the waste residue are dihydrate gypsum and ferric hydroxide, and in order to ensure thorough iron precipitation, the calcium oxide is added in a small excess amount, and the titanium gypsum is alkalescent. The discharge of titanium gypsum not only occupies a large amount of land, but also pollutes the environment. The titanium gypsum on the stacking yard can be lost due to the washing of rainwater, and meanwhile, the soluble harmful substances are dissolved in water due to the washing and soaking of the titanium gypsum by the rainwater, and the surface water and the underground water can be seriously polluted due to the flowing and circulating of the water in the environment; on the other hand, after titanium gypsum is piled up and blown by sunshine and wind, a small part of titanium gypsum will fly to the atmosphere in a powdery state and sink to the surface of a foreign object which may be contacted, thus polluting the environment and threatening the health [ li nationality, zhao shuai, in ocean ] application research of titanium gypsum in the field of building materials [ J ]. tiles, 2008, (3): 58-60].

Calcium hydroxide is an air-hardening inorganic cementing material, has a wide application range in civil engineering, and is a main raw material for cement production and flue gas desulfurization. The project takes industrial byproduct gypsum as a raw material, adopts a fluidized bed type decomposing furnace commonly used in cement plants as decomposing equipment, and decomposes the gypsum at low temperature to prepare high-purity calcium sulfide, wherein the calcium sulfide is used for preparing sulfur, and the sulfur is easy to transport. This patent not only is fit for producing the desulfurization gypsum enterprise, also is suitable for the enterprise that uses sulphuric acid, realizes the high-valued utilization of byproduct gypsum.

Disclosure of Invention

Compared with the prior art, the method can save the production cost, reduce the energy consumption, improve the efficiency and have obvious economic benefit and social benefit.

A method for recovering sulfur from industrial by-product gypsum comprises the following steps:

Adding a catalyst and a reducing agent into the industrial byproduct gypsum, uniformly mixing, carrying out reduction reaction to obtain a reaction product, and sorting the reaction product to obtain calcium sulfide; adding water into calcium sulfide, performing hydrolysis reaction to obtain calcium hydroxide and calcium hydrosulfide, and performing liquid-solid separation to obtain calcium hydroxide solid and calcium hydrosulfide solution; introducing carbon dioxide gas into the calcium hydrosulfide solution to obtain calcium carbonate precipitate and hydrogen sulfide gas; adding a trapping agent and a pH regulator into a washer, and absorbing hydrogen sulfide gas to obtain a pregnant solution; and (3) introducing the absorbed rich solution into an oxidation tank, adding a surfactant and a foaming agent, introducing air into the oxidation tank, and separating the elemental sulfur generated by oxidation of the rich solution from the solution along with the upward floating of bubbles to obtain the elemental sulfur.

The catalyst is one of hematite, waste battery anodes, chemical waste catalysts and electroplating slag, and the addition amount of the catalyst is 1-10% of the mass of industrial byproduct gypsum.

The reducing agent is one of waste plastics, waste rubber and waste engine oil, and the addition amount of the reducing agent is 1-10% of the mass of the industrial byproduct gypsum.

The trapping agent is one of manganese citrate, copper sulfate and ferric lactate, and the addition amount of the trapping agent is 0.1-5% of the mass of the industrial byproduct gypsum.

The pH regulator is one of calcium oxide, potassium carbonate and ammonium carbonate, and the addition amount of the pH regulator is 0.1-5% of the mass of the industrial byproduct gypsum.

The surfactant is one of xanthate, ethionine and nigre, and the addition amount of the surfactant is 0.01-0.1% of the mass of the industrial byproduct gypsum.

The foaming agent is one of cresol glycerol ether, methyl isobutyl carbinol, methyl amyl alcohol and polyglycol ether, and the addition amount of the foaming agent is 0.01-0.1% of the mass of the industrial byproduct gypsum.

Compared with the prior art, the invention has the following advantages:

The industrial by-product gypsum is one of phosphogypsum, desulfurized gypsum, titanium gypsum, fluorgypsum, citric acid gypsum and salt gypsum, and the main phase is calcium sulfate dihydrate or anhydrous gypsum and also contains 5-20% of adsorption water. The gypsum containing the absorbed water directly enters the quick decomposer to be preheated and decomposed, so that the drying equipment can be reduced, the heat of the flue gas can be recovered, and the cost can be reduced.

The hematite in the catalyst is waste residue generated by removing iron by a hematite method in a zinc hydrometallurgy plant; the waste battery anode is waste residue after lithium is recovered from the lithium ion battery anode, and mainly contains substances of cobalt, nickel or iron; the chemical waste catalyst is mainly a waste catalyst containing iron or nickel; the electroplating slag is nickel-containing electroplating slag and contains impurities such as Cu, Zn, Fe, Cr and the like. These catalysts can react with gypsum to form intermediate phase, promote the decomposition of gypsum and raise the conversion efficiency of gypsum by 5-20 times.

The reducing agent is one of waste plastics, waste rubber and waste engine oil, and the materials are cracked at high temperature to generate carbon monoxide to reduce gypsum to obtain a calcium sulfide product. The reducing agents are industrial solid wastes, are used, and have the effects of protecting the environment and saving resources.

the equipment adopted by the reduction reaction is a quick decomposer which is formed by connecting a preheater and a decomposing furnace in series. The number of the preheater stages is 2-6, the preheater is designed according to the principle of the preheater commonly used in the predecomposition cement kiln, materials and smoke gas move reversely in the preheater and fully exchange heat, and the outlet temperature of the smoke gas in the preheater is less than 150 ℃. The decomposing furnace is a columnar spouting turbulent bed in principle and is formed by connecting 3-8 column units with necking in series, the ratio of the inner diameter of each column unit to the inner diameter of each necking is 1.1:1-1.8:1, and the ratio of the inner height of each column unit to the inner diameter of each column is 1:1-4: 1. The combustion-supporting gas used by the rapid decomposer is a carbon dioxide/oxygen mixed gas with the ratio of 3:1-0.1:1 (carbon dioxide: oxygen, volume ratio), and compared with the air, the carbon dioxide/oxygen mixed gas can avoid the generation of nitrogen oxides and the pollution of the nitrogen oxides; the main component of the flue gas is carbon dioxide, which can be recycled and also can be used as a raw material in the subsequent working procedures. Each column unit has inlets for fuel and combustion supporting gas, so that the atmosphere of each column unit can be adjusted separately. The temperature of the decomposing furnace is 800-. In the flue gas ascending pipeline after the decomposed materials are separated from the flue gas, combustion-supporting gas is introduced, and unreacted carbon monoxide gas is oxidized into carbon dioxide. The catalyst is magnetic substance, which is beneficial to magnetic separation and can be recycled. By using the method, the purity of the calcium sulfide is higher than 95%. In addition, the auxiliary fuel adopted by the decomposing furnace in the patent is one of high-temperature blast furnace gas (more than or equal to 1000 ℃) and combustible waste gas generated in the coal chemical industry, and the waste gas is used to realize resource recycling.

The amount of water added into the calcium sulfide is 300 percent of the mass of the industrial by-product gypsum. Hydrolyzing to obtain calcium hydroxide precipitate and calcium hydrosulfide solution, and performing solid-liquid separation; adding carbon dioxide gas into the calcium hydrosulfide solution to obtain calcium carbonate precipitate and hydrogen sulfide gas, wherein the adding amount of the carbon dioxide is 30-50% of the mass of the industrial byproduct gypsum, and the water solution obtained after the calcium carbonate precipitate is filtered can be used for hydrolyzing calcium sulfide to realize the recycling of water. The calcium hydroxide precipitate can be used in the field of construction and can also be used in the field of metallurgy for neutralizing waste acid. The calcium carbonate can be used as a coal-fired flue gas desulfurizer to obtain desulfurized gypsum for recycling, and can also be used as a raw material of a cement plant.

the trapping agent is added into the scrubber and can react with the hydrogen sulfide gas to generate new substances to enter the solution, so that the trapping of the hydrogen sulfide gas is realized, and the trapping agent has high trapping efficiency, and the trapping rate is more than 99.9 percent. The pH regulator can stabilize the pH value of the solution, and is beneficial to capture sulfur dioxide gas by the capture agent.

And introducing air into the oxidation tank, and oxidizing the trapping agent and new substances generated by hydrogen sulfide to obtain elemental sulfur and realize the regeneration of the trapping agent. The elemental sulfur has fine particle size and is difficult to separate when dispersed in a solution. And adding a surfactant and a foaming agent into the oxidation tank, so that the elemental sulfur floats upwards along with bubbles to realize the separation of the solution and the sulfur, wherein the content of the elemental sulfur in the solution after the liquid-solid separation is less than 0.05 percent. The surface active agent improves the surface property of sulfur, is easy to be adsorbed on foam generated by a foaming agent, enables elemental sulfur to float upwards, and realizes the quick separation of sulfur and solution. And returning the desulfurized solution to the scrubber for recycling.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Adding a catalyst and a reducing agent into the industrial byproduct gypsum, uniformly mixing, carrying out reduction reaction to obtain a reaction product, and sorting the reaction product to obtain calcium sulfide; adding water into calcium sulfide, performing hydrolysis reaction to obtain calcium hydroxide and calcium hydrosulfide, and performing liquid-solid separation to obtain calcium hydroxide solid and calcium hydrosulfide solution; introducing carbon dioxide gas into the calcium hydrosulfide solution to obtain calcium carbonate precipitate and hydrogen sulfide gas; adding a trapping agent and a pH regulator into a washer, and absorbing hydrogen sulfide gas to obtain a pregnant solution; and (3) introducing the absorbed rich solution into an oxidation tank, adding a surfactant and a foaming agent, introducing air into the oxidation tank, and separating the elemental sulfur generated by oxidation of the rich solution from the solution along with the upward floating of bubbles to obtain the elemental sulfur. The formula of the catalyst and the reducing agent in the raw materials is shown in the table 1; the formula of the trapping agent and the pH regulator is shown in the table 2; the formulations of the surfactant and the foaming agent are shown in Table 3.

TABLE 1

TABLE 2

TABLE 3

The embodiments of the invention can be implemented and achieve the aim of the invention. The present invention is not limited to these examples.