Comprehensive treatment and recycling process for acidic waste gypsum
Technical Field
The invention belongs to the fields of environmental protection and chemical engineering, and particularly relates to a process for comprehensively treating and recycling acidic waste gypsum.
Background
The acid waste gypsum belongs to dangerous waste and is generally mixed with organic matters, heavy metals and the like. Generally, a temporary stacking disposal method or a landfill method is adopted, secondary pollution is caused by stacking, the landfill treatment cost is high, and the serious waste of sulfur resources is caused. Therefore, a new treatment process needs to be developed to recycle the waste and make the waste harmless and recyclable.
The invention with application number 98101761.4 discloses a method for catalytic reduction of desulfurized waste residue, phosphogypsum or natural gypsum, which takes a compound of iron, nickel, magnesium and sodium as a catalyst, when the temperature is higher than 650 ℃, more than 95% of calcium sulfate can be reduced into calcium sulfide, and the obtained calcium sulfide can be further converted into sodium sulfide, sodium thiosulfide or sulfur. However, in the reduction process, a large amount of composite metal compounds are used as catalysts, and carbon monoxide or hydrogen or the mixed gas of the carbon monoxide and the hydrogen is used as a reducing agent, so that the cost is high; meanwhile, tail gas generated by the reaction is not treated, so that the environment is polluted.
The invention patent with application number 201110192180.4 discloses a method for preparing calcium oxide and sulfur by desulfurized gypsum double-atmosphere fluidized roasting, wherein the aged desulfurized gypsum is dried and dehydrated, and is preheated in a multistage suspension heat exchanger, the hot gypsum enters a circulating fluidized bed decomposing furnace, and primary air and secondary air are introduced for decomposition. And cooling the discharged hot calcium oxide to serve as a desulfurizer for later use. And the discharged flue gas containing sulfur dioxide enters a multistage suspension heat exchanger. And removing calcium oxide dust in the cooled hot flue gas by using multistage dust removal equipment. The flue gas after dust removal is sent into a high-temperature-resistant high-efficiency filter to further remove dust, the clean flue gas is sent into a sulfur recovery system, a sulfur product is prepared through the working procedures of thermal reduction, catalytic reduction, Claus reaction and the like, and the Claus tail gas is sent to a coal-fired boiler of a power plant for incineration treatment. The method has good and environmental-friendly benefits and stronger economic advantages. However, in the process, a large amount of preheated combustion-supporting air is needed, a reducing atmosphere is provided in an incomplete combustion mode, secondary air is fed to provide an oxidizing atmosphere, the air feeding amount is not controlled well, and the desulfurized gypsum cannot be completely decomposed; the desulfurized gypsum needs to be preheated and subjected to heat exchange treatment, and the process is complex and consumes long time.
The invention discloses a new process for preparing sulfur from industrial waste gypsum, which adopts industrial waste gypsum and carbonaceous reducing material to reduce and prepare sulfur or byproduct cement for preparing sulfur, wherein the industrial waste slag is waste gypsum slag mud discharged in the production of phosphogypsum, desulfurized gypsum, fluorgypsum, lemon gypsum and titanium white or waste slag mainly comprising calcium sulfate discharged in the industrial production, and the carbonaceous reducing material refers to coal, coke, petroleum slag or asphalt. The reduction process is a one-stage or multi-stage reduction sulfur production process, and the tail gas is a one-stage or multi-stage catalytic reduction and purification process. The invention can fully utilize the industrial waste gypsum and by-produce cement, has the advantages of small investment, low cost, simple process, environmental protection, resource saving, waste material changing and remarkable social and economic benefits. But the temperature required in the reduction process of the process is higher, and the process operation difficulty is large; the sulfur production process and the tail gas treatment process are complicated, catalysts are needed in the tail gas treatment process, unreacted tail gas still needs to be discharged, resources are wasted to a certain extent, and the environment is polluted to a certain extent.
The invention with the application number of 200910094110.8 discloses a method for preparing a calcareous raw material and SO2 by decomposing phosphogypsum with high-sulfur petroleum coke, namely, the phosphogypsum is reduced and decomposed by the high-sulfur petroleum coke with the carbon content of more than 80 percent and the sulfur mass fraction of more than 2 to 6 percent, furnace gas with the volume percentage content of SO2 of more than or equal to 15 percent is produced, the furnace gas can be directly used as qualified raw material gas of a two-way absorption acid preparation process, a solid product CaO with the mass percentage content of more than 50 percent is produced, the solid product CaO can be directly used as a chemical raw material, such as cement preparation, no waste is generated in the process, the decomposition rate of the phosphogypsum. The phosphogypsum decomposed by the process does not need to be pretreated, the concentration of SO2 in furnace gas is stable, the carbon content and the heat value in high-sulfur petroleum coke are higher, and the contents of nitrogen and sulfur are higher compared with other fuels, SO that the reaction temperature is reduced, the energy consumption is reduced, the production cost is reduced, no environmental pollution is caused, waste materials are changed into valuable materials, each component of the phosphogypsum is utilized to the maximum extent in the process, and the problems of harmlessness and outgoing of the phosphogypsum which is a hazardous waste are solved. However, the flue gas generated by decomposing the byproduct sulfur dioxide is used for producing liquid sulfuric acid products, the actual condition of a power plant is not considered, on one hand, the power plant is not a professional chemical enterprise, the chemical production line is too long to facilitate production operation management, on the other hand, the added value of the sulfuric acid products is low, the sulfuric acid products are not easy to store and transport, and the risk that the production is affected by expansion of the sulfuric acid warehouse is caused due to the fact that the sulfuric acid.
The invention patent with application number 201310285635.6 discloses a method for solidifying heavy metals in electrolytic manganese slag and co-producing sulfur, which comprises the following basic steps: uniformly mixing a raw material containing calcium sulfite and/or calcium sulfate and a carbon-based reducing agent in a molar ratio of 1: 2.0-3.0, and roasting at 800-1000 ℃ for 1.5-2 h to obtain calcine containing calcium sulfide, wherein the yield of the calcium sulfide is over 90%; uniformly mixing electrolytic manganese slag sieved by a 50-400-mesh sieve and calcine containing calcium sulfide according to a dry basis mass ratio of 3-8: 1, adding water to enable the mass ratio of water to the electrolytic manganese slag to be 4-6: 1, stirring and reacting for 2-4 hours at room temperature, and filtering to obtain filtrate and filter residue; and filter residues are solidified electrolytic manganese residues, filtrate is kept stand at room temperature for 24-48 hours to separate out sulfur, the sulfur and the filtrate are filtered and separated again, the yield of the sulfur is 30-45 kg/t of manganese residues, and the filtrate is recycled as water. The solidification rate of cadmium, cobalt, copper, nickel, iron, manganese and zinc in the electrolytic manganese slag can reach more than 93 percent, and the leaching toxicity of the electrolytic manganese slag after the heavy metal is solidified meets the relevant national standard. However, tail gas generated after the raw material containing calcium sulfite and/or calcium sulfate reacts with the carbon-based reducing agent is not treated, and thus, the tail gas causes harm to the environment.
The technological results all relate to a method for preparing sulfur or calcareous raw materials by taking waste gypsum as a main raw material, but the problems of high energy consumption, long consumed time, difficult control, insufficient resource utilization and the like exist in different degrees.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a process for comprehensively treating and recycling acid waste gypsum, which has the characteristics of low reduction reaction temperature, short process time, easy control and full resource utilization.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a process for comprehensively treating and recycling acid waste gypsum comprises the following steps:
(1) respectively drying and mixing the acidic waste gypsum and the carbonaceous material;
(2) ball-milling and screening the mixture of the acidic waste gypsum and the carbonaceous material to obtain a raw material;
(3) feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker;
(4) putting the solid clinker into sulfuric acid wastewater to obtain an acidic waste gypsum precipitate and hydrogen sulfide gas; after the reaction is finished, adding one or more of lime milk, quicklime or carbonaceous materials into the sulfuric acid wastewater for mixing;
(5) and (2) carrying out catalytic oxidation on hydrogen sulfide gas by using a catalyst to prepare crude sulfur, and carrying out solid-liquid separation, melt separation and cooling on the crude sulfur to obtain a refined sulfur product.
(6) Recycling the acidic waste gypsum precipitate obtained in the step (4) according to the steps (1) to (5); or drying the mixture obtained by mixing the acidic waste gypsum precipitate in the step (4) with the carbonaceous material through sulfuric acid wastewater, and then circulating according to the steps (2) to (5).
Further, in the step (1), the moisture content of the carbon material and the dried acid waste gypsum is less than or equal to 5%, and the molar mass ratio of the carbon material to the calcium of the acid waste gypsum is 1.5-5: 1.
further, the carbonaceous material in the step (1) is one or a mixture of more of activated carbon, coke, petroleum coke, biomass carbon and carbon-containing waste residue, and the mass fraction omega (C) of the content of the simple substance carbon in the carbonaceous material is more than or equal to 80%.
Further, the acid waste gypsum in the step (1) is one or a mixture of industrial acid waste gypsum and acid waste gypsum precipitate generated in the step (4), and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4)≥80%;
Further, in the step (2), the particle size of the raw material is 20-100 meshes.
Further, in the step (3), the thermal cracking conditions of the high-temperature thermal cracking furnace are that the oxygen concentration is less than or equal to 1%, the reaction temperature is 700-; the mass fraction omega (CaS) of the content of the calcium sulfide in the solid clinker is more than or equal to 40 percent.
Further, in the step (4), the initial pH value of the sulfuric acid wastewater is less than 6.0.
Preferably, the initial mass concentration of the sulfuric acid in the sulfuric acid wastewater is 0.5-30%.
Further, in the step (4), after the solid clinker is added into the sulfuric acid wastewater, when the pH of the sulfuric acid wastewater is less than 6.0 after the reaction is finished, one or two of lime milk and quicklime are added and mixed, the pH of the sulfuric acid wastewater is adjusted to 6.0-9.0, and simultaneously one or two of lime milk and quicklime are mixed and reacted with the sulfuric acid wastewater to generate the acidic waste gypsum precipitate.
Preferably, in the step (4), after the reaction of the solid clinker and the sulfuric acid wastewater is finished, a certain amount of carbonaceous material is added into the reaction system, and the molar mass ratio of carbon to calcium in the reaction system is adjusted to 1.5-5: 1, after uniformly mixing a carbonaceous material and the acidic waste gypsum precipitate in sulfuric acid wastewater, carrying out plate-and-frame filter pressing on the sulfuric acid wastewater to obtain a mixture of the acidic waste gypsum precipitate and the carbonaceous material;
the operating pressure of the plate frame filter pressing is 0.3-1.6 Mpa.
In the step (6), the water content of the mixture of the acidic waste gypsum precipitate and the carbonaceous material after drying is less than or equal to 5 percent;
further, in the step (5), the catalytic oxidation of hydrogen sulfide gas is carried out in an organic phase catalytic oxidation reactor.
Further, in the step (5), the catalyst is an organic desulfurizer, and the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 15-25: 1.
Further, in the step (5), the organic desulfurizer is recycled after being regenerated.
Further, in the step (5), the particle size of the crude sulfur is 10-70 μm, and the melting separation temperature is 130-140 ℃.
Has the advantages that:
1. the comprehensive treatment and recycling process of the acid waste gypsum can recover sulfur elements in the sulfuric acid-containing wastewater to prepare sulfur, so that resources are fully utilized, wherein the removal efficiency of hydrogen sulfide is more than or equal to 99%, 0.2-0.4 part of sulfur products can be obtained from each part of acid waste gypsum, and the yield of the sulfur in the final organic phase catalytic oxidation reactor is more than or equal to 97%; the purity of the refined sulfur product reaches the standard of industrial sulfur second grade product.
2. The process can effectively utilize the surface adsorption effect of the carbonaceous material, can effectively adsorb partial organic components in the sulfuric acid wastewater, and obviously reduce the chemical oxygen demand of the wastewater, and simultaneously can effectively reduce the thermal catalytic reduction temperature of the waste gypsum and reduce the energy consumption, wherein the pyrolysis temperature of the waste gypsum and the carbonaceous material is 700-1450 ℃, which is obviously lower than that of 900-1450 ℃ in the prior art.
3. Effectively neutralizing sulfuric acid wastewater: in the step (4), the solid clinker of the sulfuric acid wastewater is added, and not only can the solid clinker react to generate H in the process of adding the sulfuric acid wastewater2The S gas provides accumulation of precursor substances for preparing sulfur and can effectively neutralize sulfuric acid wastewater. Meanwhile, after the reaction of the solid clinker and the sulfuric acid wastewater is finished, when the pH value of the sulfuric acid wastewater is still less than 6, one or two of lime milk and quicklime are selectively added and mixed, so that the sulfuric acid wastewater can be continuously neutralized to reach the recovery standard of the sulfuric acid wastewater, calcium in a reaction system is supplemented to a certain extent, the loss of calcium in the reaction process is filled, and acidic waste gypsum precipitates generated by the lime milk or the quicklime and the sulfuric acid wastewater in the reaction system can be continuously returned to the steps (1) to (5) of the acidic waste gypsum comprehensive treatment process for circulation.
4. The reaction system effectively circulates calcium element: in the step (4), the acidic waste gypsum precipitate which is generated by the reaction of the solid clinker and the sulfuric acid wastewater and takes calcium sulfate as a main component can be fed back to the step (1) to be used as a supplementary raw material of the acidic waste gypsum and enter the circulation of the reaction system again, so that the cyclic utilization of calcium in the system is maintained, and the use amount of lime milk or quicklime is obviously reduced.
5. The reaction is mixed evenly, the mixing cost is reduced: in the step (4), after the sulfuric acid wastewater is neutralized, a carbonaceous material can be selectively added into the sulfuric acid wastewater, on one hand, the carbonaceous material can react with lime milk or quicklime added in the last step of the reaction system to generate an acidic waste gypsum precipitate, and on the other hand, under the condition that the sulfuric acid wastewater is used as a reaction medium, the carbonaceous material can be more fully and uniformly mixed with the acidic waste gypsum precipitate in the reaction system, and raw materials do not need to be respectively dried and mixed, so that the reaction cost is greatly reduced, and meanwhile, the reaction in the circulation is more fully realized through the mixing.
It should be noted that the technical effect of the comprehensive treatment and recycling process of the acid waste gypsum is the result of mutual cooperation and interaction of the technical characteristics and method characteristics of each component and each process link, and is not the superposition of simple technical characteristics, and the effect produced by the organic combination and cooperation of the technical characteristics of each component and each process link far exceeds the superposition of functions and effects of each single technical characteristic, so that the comprehensive treatment and recycling process of the acid waste gypsum has better advancement and practicability.
Drawings
FIG. 1 is a process for comprehensive treatment and recycling of acid waste gypsum (method 1);
FIG. 2 shows the comprehensive treatment and recycling process of acid waste gypsum (method 2).
Detailed Description
The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications in the components and amounts of the materials used in these embodiments can be made without departing from the spirit and scope of the invention.
Example 1
Referring to the attached figure 1 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum comprises the following steps:
(1) respectively drying the acid waste gypsum and the carbonaceous material, wherein the water content after drying is 4%, and the molar mass ratio of carbon in the carbonaceous material to calcium in the acid waste gypsum is 3.5: 1, mixing.
Wherein, the carbonaceous material is selected from activated carbon, and the mass fraction omega (C) of the simple substance carbon content in the activated carbon is 85 percent; the acid waste gypsum is a mixture of industrial acid waste gypsum and acid waste gypsum precipitate generated in the step (4), and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4) The content was 85%.
(2) The mixture of the acid waste gypsum and the carbonaceous material is ball-milled and screened to prepare the raw material, and the particle size of the raw material is 60 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking conditions of the high-temperature thermal cracking furnace are that the oxygen concentration is 0.5 percent, the reaction temperature is 750 ℃, and the reaction time is 1 h; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 70%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 3.0, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 15%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; and after the reaction is finished and the pH value of the sulfuric acid wastewater is 5.0, adding lime milk into the sulfuric acid wastewater, adjusting the pH value of the sulfuric acid wastewater to 7.0, and reacting the lime milk with the sulfuric acid wastewater to continuously generate the acidic waste gypsum.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 20:1, the particle size of the prepared crude sulfur is 40 mu m, the melt separation temperature is 135 ℃, the hydrogen sulfide removal efficiency reaches 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) carrying out plate-and-frame filter pressing on the acidic wastewater after the reaction in the step (4) to obtain an acidic waste gypsum precipitate, and circulating according to the steps (1) to (5).
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.35 part of sulfur product can be obtained from each part of the acid waste gypsum.
Example 2
Referring to the attached figure 1 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum comprises the following steps:
(1) respectively drying the acid waste gypsum and the carbonaceous material, wherein the water content of the dried acid waste gypsum is 3 percent, the water content of the carbonaceous material is 2 percent, and the ratio of carbon in the carbonaceous material to calcium in the acid waste gypsum is 1.5: 1, mixing.
WhereinThe carbonaceous material is selected from coke and petroleum coke which are mixed according to any proportion, the mass fraction omega (C) of the content of simple substance carbon in the coke and petroleum coke mixture is 80 percent, the acid waste gypsum is the acid waste gypsum precipitate generated in the step (4), and the mass fraction omega (CaSO) of the content of calcium sulfate in the acid waste gypsum is4) 80 percent;
(2) the mixture of the acid waste gypsum and the carbonaceous material is ball-milled and screened to prepare the raw material, and the particle size of the raw material is 20 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking condition of the high-temperature thermal cracking furnace is that the oxygen concentration is 0.1 percent, the reaction temperature is 700 ℃, and the reaction time is 1 h; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 45%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 4.5, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 0.5%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; after the reaction is finished, the pH value of the sulfuric acid wastewater is 5.5; adding quicklime into the sulfuric acid wastewater, adjusting the pH of the sulfuric acid wastewater to 7.5, reacting limestone with the sulfuric acid wastewater to continuously generate acidic waste gypsum, and reacting lime milk with the sulfuric acid wastewater to continuously generate the acidic waste gypsum.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 15:1, the particle size of the prepared crude sulfur is 10 mu m, the melt separation temperature is 130 ℃, the hydrogen sulfide removal efficiency is 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) carrying out plate-and-frame filter pressing on the acidic wastewater after the reaction in the step (4) to obtain an acidic waste gypsum precipitate, and circulating according to the steps (1) to (5).
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.2 part of sulfur product can be obtained in each part of the acid waste gypsum.
Example 3
Referring to the attached figure 1 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum comprises the following steps:
(1) respectively drying the acidic waste gypsum and the carbonaceous material, wherein the water content after drying is less than or equal to 5 percent, and the acidic waste gypsum and the carbonaceous material are prepared according to the carbonaceous material
The molar mass ratio of carbon (b) to calcium (c) of the acidic waste gypsum is 5:1, mixing.
Wherein, the carbonaceous material selects carbon-containing waste residues, and the mass fraction omega (C) of the carbon-containing waste residues is 90 percent; the acid waste gypsum is a mixture of industrial acid waste gypsum and the acid waste gypsum generated in the step (4), and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4) The content was 90%.
(2) The mixture of the acid waste gypsum and the carbonaceous material is ball-milled and screened to prepare the raw material, and the particle size of the raw material is 100 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking condition of the high-temperature thermal cracking furnace is that the oxygen concentration is 1 percent, the reaction temperature is 850 ℃, and the reaction time is 1.5 h; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 80%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 0.5, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 30%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; and after the reaction is finished and the pH value of the sulfuric acid wastewater is 3.2, adding a mixture of lime milk and quicklime into the sulfuric acid wastewater, adjusting the pH value of the sulfuric acid wastewater to 7.5, and reacting the lime milk and the sulfuric acid wastewater to continuously generate the acidic waste gypsum.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 25:1, the particle size of the prepared crude sulfur is 70 mu m, the melt separation temperature is 140 ℃, the hydrogen sulfide removal efficiency is 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) carrying out plate-and-frame filter pressing on the acidic wastewater after the reaction in the step (4) to obtain an acidic waste gypsum precipitate, and circulating according to the steps (1) to (5).
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.38 part of sulfur product can be obtained from each part of the acid waste gypsum.
Example 4
Referring to the attached figure 2 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum comprises the following steps:
(1) respectively drying the acid waste gypsum and the carbonaceous material, wherein the water content of the dried material is 3%, and the molar mass ratio of carbon in the carbonaceous material to calcium in the acid waste gypsum is 3: 1, mixing.
Wherein the carbonaceous material is a mixture of biomass carbon and carbon-containing waste residue, and the mass fraction omega (C) of the simple substance carbon content is 85%; the acid waste gypsum is industrial acid waste gypsum, and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4) The content was 85%.
(2) The mixture of the acid waste gypsum and the carbonaceous material is ball-milled and screened to prepare the raw material, and the particle size of the raw material is 70 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking conditions of the high-temperature thermal cracking furnace are that the oxygen concentration is 0.5 percent, the reaction temperature is 750 ℃, and the reaction time is 1 h; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 60%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 1.0, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 10%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; after the reaction is finished and the pH value of the sulfuric acid wastewater is 4.0, adding lime milk into the sulfuric acid wastewater, adjusting the pH value of the sulfuric acid wastewater to 9.0, and reacting the lime milk with the sulfuric acid wastewater to continuously generate acidic waste gypsum;
after the pH value of the sulfuric acid wastewater is adjusted, adding a certain amount of carbonaceous reducing material into the reaction system, and adjusting the molar mass ratio of carbon to calcium in the reaction system to 3: 1, uniformly mixing the carbonaceous material and the acidic waste gypsum precipitate in the sulfuric acid wastewater, and carrying out plate-and-frame filter pressing on the sulfuric acid wastewater to obtain a mixture of the acidic waste gypsum precipitate and the carbonaceous material, wherein the operation pressure of the plate-and-frame filter pressing is 0.7 MPa.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 20:1, the particle size of the prepared crude sulfur is 30 mu m, the melt separation temperature is 130 ℃, the hydrogen sulfide removal efficiency is 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) drying the mixture of the acidic waste gypsum precipitate and the carbonaceous material in the step (4), and then circulating according to the steps (2) to (5), wherein the water content of the dried mixture of the waste gypsum precipitate and the carbonaceous material is 3%.
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.3 part of sulfur product can be obtained in each part of the acid waste gypsum.
Example 5
Referring to the attached figure 2 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum is characterized by comprising the following steps:
(1) respectively drying the acid waste gypsum and the carbonaceous material, wherein after drying, the water content of the acid waste gypsum is 2%, the water content of the carbonaceous material is 3%, and the ratio of carbon in the carbonaceous material to calcium in the acid waste gypsum is 4: 1, mixing.
The carbon material is prepared by mixing activated carbon and biomass carbon, and the mass fraction omega (C) of the elemental carbon content in the carbon material is 80%; the acid waste gypsum is one or a mixture of industrial acid waste gypsum or acid waste gypsum precipitate generated in the step (4), and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4)≥80%;
(2) The mixture of the acid waste gypsum and the carbonaceous material is ball-milled and sieved to prepare the raw material, and the particle size of the raw material is 80 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking conditions of the high-temperature thermal cracking furnace are that the oxygen concentration is 0.8 percent, the reaction temperature is 750 ℃, and the reaction time is 1.2 hours; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 60%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 2.0, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 15%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; after the reaction is finished, the pH value is 6.5;
then, adding a certain amount of carbonaceous reducing material into the reaction system, and adjusting the molar mass ratio of carbon to calcium in the reaction system to be 4: 1, uniformly mixing a carbonaceous material and the acidic waste gypsum precipitate in sulfuric acid wastewater, and carrying out plate-and-frame filter pressing on the sulfuric acid wastewater to obtain a mixture of the acidic waste gypsum precipitate and the carbonaceous material, wherein the operating pressure of the plate-and-frame filter pressing is 0.3 Mpa.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 20:1, the particle size of the prepared crude sulfur is 50 μm, the melt separation temperature is 135 ℃, the hydrogen sulfide removal efficiency is 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) drying the mixture of the acidic waste gypsum precipitate in the step (4) and the carbonaceous material, and then circulating according to the steps (2) to (5), wherein the water content of the dried mixture is 2%.
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.35 part of sulfur product can be obtained from each part of the acid waste gypsum.
Example 6
Referring to the attached figure 2 of the specification, the comprehensive treatment and recycling process of the acid waste gypsum is characterized by comprising the following steps:
(1) respectively drying the acid waste gypsum and the carbonaceous material, wherein after drying, the water content of the acid waste gypsum is 5 percent, the water content of the carbonaceous material is 3 percent, and the ratio of carbon in the carbonaceous material to calcium in the acid waste gypsum is 5:1, mixing.
Wherein, the carbonaceous material is selected from the mixture of activated carbon and carbon-containing waste residue, and the mass fraction omega (C) of the content of simple substance carbon in the carbonaceous material is 85 percent; the acid waste gypsum is one or a mixture of industrial acid waste gypsum or acid waste gypsum precipitate generated in the step (4), and the mass fraction omega (CaSO) of the calcium sulfate content in the acid waste gypsum4) 80 percent;
(2) the mixture of the acid waste gypsum and the carbonaceous material is ball-milled and sieved to prepare the raw material, and the particle size of the raw material is 80 meshes.
(3) Feeding the raw materials into a thermal cracking furnace for thermal cracking to obtain solid clinker; the thermal cracking conditions of the high-temperature thermal cracking furnace are that the oxygen concentration is 0.4 percent, the reaction temperature is 750 ℃, and the reaction time is 1 h; the mass fraction omega (CaS) of the calcium sulfide content in the solid clinker is 60%.
(4) Putting the solid clinker into sulfuric acid wastewater with initial pH of 1.6, wherein the initial sulfuric acid mass concentration in the sulfuric acid wastewater is 20%; obtaining acid waste gypsum precipitate and hydrogen sulfide gas; after the reaction is finished; adding lime milk into the sulfuric acid wastewater, adjusting the pH value of the sulfuric acid wastewater to 8.0, and reacting the lime milk with the sulfuric acid wastewater to continuously generate acidic waste gypsum;
then adding a certain amount of carbonaceous reducing material into the reaction system, and adjusting the molar mass ratio of carbon to calcium in the reaction system to 5:1, uniformly mixing a carbonaceous material and the acidic waste gypsum precipitate in sulfuric acid wastewater, and carrying out plate-and-frame filter pressing on the sulfuric acid wastewater to obtain a mixture of the acidic waste gypsum precipitate and the carbonaceous material, wherein the operating pressure of the plate-and-frame filter pressing is 1.6 Mpa.
(5) Introducing hydrogen sulfide gas into an organic phase catalytic oxidation reactor, preparing crude sulfur under the catalytic oxidation action of an organic desulfurizer, performing solid-liquid separation, melt separation and cooling to obtain a refined sulfur product, and recycling the regenerated organic desulfurizer, wherein the liquid-gas ratio of the desulfurizer to the hydrogen sulfide gas is 22:1, the particle size of the prepared crude sulfur is 25 mu m, the melt separation temperature is 130 ℃, the hydrogen sulfide removal efficiency is 100%, and the purity of the refined sulfur product reaches the second grade standard of industrial sulfur.
(6) And (3) drying the mixture of the acidic waste gypsum precipitate in the step (4) and the carbonaceous material, and then circulating according to the steps (2) to (5), wherein the water content of the dried mixture is 3%.
In the comprehensive treatment and recycling process of the acid waste gypsum, 0.4 part of sulfur product can be obtained in each part of the acid waste gypsum.