阅读说明：本技术 利用磷石膏制备高品质建筑石膏的方法 (Method for preparing high-quality building gypsum by using phosphogypsum ) 是由 周爱丽 于 2021-11-04 设计创作，主要内容包括：利用磷石膏制备高品质建筑石膏的方法,包括以下步骤：将化工厂排出的磷石膏渣先输送至振动分选机分选,然后送入清洗机中利用工业废水进行初步冲洗,去掉矿物杂质；再在清洗机中通过真空过滤、多次喷淋水洗,加入改性剂调节PH,抽干；将清洗过的磷石膏原料进行破碎,送入干燥机内进行烘干,干燥温度为100～150℃；烘干后再进行细磨,然后输送至煅烧炉进行煅烧,煅烧温度为180～240℃；煅烧后的物料通过冷却出料输送机构进行降温及输送,冷却后进行选粉,然后进入均化库进行均化；本发明可有效处理化工固废磷石膏,不仅能避免因堆放而引起的二次污染问题,还可以把副产石膏的化工工业和建材工业有机结合起来,变废为宝,实现磷肥和磷酸等工业的无废渣排放。(The method for preparing high-quality building gypsum by using phosphogypsum comprises the following steps: conveying phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, and then conveying the phosphogypsum slag to a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities; then vacuum filtering, spraying and washing for many times in a cleaning machine, adding a modifier to adjust the PH value, and pumping to dry; crushing the cleaned phosphogypsum raw material, and sending the crushed phosphogypsum raw material into a drier for drying, wherein the drying temperature is 100-150 ℃; drying, finely grinding, and then conveying to a calcining furnace for calcining, wherein the calcining temperature is 180-240 ℃; cooling and conveying the calcined material through a cooling discharge conveying mechanism, selecting powder after cooling, and then homogenizing in a homogenizing warehouse; the invention can effectively treat chemical solid waste phosphogypsum, not only can avoid the problem of secondary pollution caused by stacking, but also can organically combine the chemical industry and the building material industry of the byproduct gypsum, change waste into valuable and realize the non-waste residue discharge of the industries such as phosphate fertilizer, phosphoric acid and the like.)

1. The method for preparing high-quality building gypsum by using phosphogypsum is characterized by comprising the following steps:

(1) conveying phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, and then conveying the phosphogypsum slag to a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities;

(2) then vacuum filtering, spraying and washing for many times in a washing machine, adding a modifier to adjust the PH, and draining for later use;

(3) crushing the cleaned phosphogypsum raw material, and sending the crushed phosphogypsum raw material into a drier for primary drying, wherein the drying temperature is 100-150 ℃;

(4) the dried phosphogypsum is finely ground and then conveyed to a calcining furnace for calcining, wherein the calcining temperature is 180-240 ℃;

(5) the calcined material is cooled and conveyed by a cooling discharge conveying mechanism, and then is subjected to powder selection after being cooled, and then enters a homogenizing warehouse for homogenization.

2. The method for preparing high-quality building gypsum by using phosphogypsum according to claim 1, wherein in the step (2), the content of soluble phosphorus in the phosphogypsum is not more than 0.2% and the content of soluble fluorine in the phosphogypsum is not more than 0.1% through 3-5 times of filtering and spraying.

3. The method for preparing high-quality building gypsum by using phosphogypsum according to claim 1, wherein in the step (2), the modifier is one of calcium hydroxide solution and sodium hydroxide solution, and the pH value is adjusted to be between 5 and 7.

4. The method for preparing high-quality building gypsum by using phosphogypsum according to claim 1, wherein in the step (3), the particle size of the crushed raw material is less than 80 μm.

5. The method for preparing high-quality building gypsum by using phosphogypsum according to claim 1, wherein in the step (4), the particle size of the ground raw material is 5-60 μm.

6. The method for preparing high-quality building gypsum by using phosphogypsum according to claim 1, wherein the heat source used in the steps (3) and (4) is hot steam, and the waste heat discharged from the calcining furnace is introduced into a drier for recycling.

Technical Field

The invention relates to the field of utilization of phosphogypsum, in particular to a method for preparing high-quality building gypsum by using the phosphogypsum.

Background

The phosphogypsum is industrial waste residue generated in the process of preparing phosphoric acid by reacting phosphorite with sulfuric acid in the wet-process phosphoric acid production process. At present, the annual emission amount of the phosphogypsum all over the world reaches more than 2 hundred million tons, but the utilization rate of the phosphogypsum is less than 10 percent, and the treatment and the comprehensive utilization of the phosphogypsum become a worldwide problem. The yield of phosphate fertilizer is the first world in China, a large amount of phosphoric acid products are needed for producing the phosphate fertilizer, and a large amount of phosphogypsum waste residues are also produced. The stacking of the phosphogypsum occupies a large amount of land, and the soluble P, F and other harmful components diffuse and permeate to the surrounding environment through a medium to form a secondary pollution environment. Therefore, the phosphogypsum harmless treatment and comprehensive utilization become key research projects in the fields of solid waste treatment and disposal and resource utilization.

The treatment and disposal problem of the phosphogypsum becomes a main research object for treating the solid waste residue in the environment, and also becomes a key for restricting the sustainable development of the phosphate fertilizer industry, at present, a more effective treatment method is to calcine and prepare the building gypsum and carry out resource utilization on the building gypsum, and the treatment method has the advantages of large calcination amount, high utilization efficiency, simple equipment and low calcination cost; however, in the case of phosphogypsum, due to the existence of impurities such as phosphorus, fluorine, organic matters and the like, the building gypsum produced by the traditional preparation process often has the unfavorable results of overlong setting time, too low strength and the like, and the application of the phosphogypsum in a large amount is severely restricted, so that a method for preparing high-quality building gypsum is urgently needed.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for preparing high-quality building gypsum by using phosphogypsum, which improves the quality of the prepared building gypsum and can meet the requirements of producing various gypsum products.

The technical scheme adopted by the invention is as follows:

the method for preparing high-quality building gypsum by using phosphogypsum comprises the following steps:

(1) conveying phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, and then conveying the phosphogypsum slag to a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities;

(2) then vacuum filtering, spraying and washing for many times in a washing machine, adding a modifier to adjust the PH, and draining for later use;

(3) crushing the cleaned phosphogypsum raw material, and sending the crushed phosphogypsum raw material into a drier for primary drying, wherein the drying temperature is 100-150 ℃;

(4) the dried phosphogypsum is finely ground and then conveyed to a calcining furnace for calcining, wherein the calcining temperature is 180-240 ℃;

(5) the calcined material is cooled and conveyed by a cooling discharge conveying mechanism, and then is subjected to powder selection after being cooled, and then enters a homogenizing warehouse for homogenization.

Preferably, in the step (2), the content of soluble phosphorus and the content of soluble fluorine in the phosphogypsum are respectively not more than 0.2% and not more than 0.1% through 3-5 times of filtering and spraying.

Preferably, in the step (2), the modifier is one of a calcium hydroxide solution and a sodium hydroxide solution, and the adjusted pH value is between 5 and 7.

Preferably, in step (3), the particle size of the crushed raw material is less than 80 μm.

Preferably, in the step (4), the particle size of the ground raw material is 5-60 μm.

Preferably, the heat source used in steps (3) and (4) is hot steam, and the residual heat discharged from the calcining furnace is introduced into a dryer for recycling.

The invention has the beneficial effects that:

(1) by adding the processes of cleaning, spraying and filtering the phosphogypsum, the content of soluble phosphorus in the phosphogypsum is controlled to be not more than 0.2 percent and the content of soluble fluorine in the phosphogypsum is controlled to be not more than 0.1 percent, so that the quality of the produced building gypsum is improved, the requirement of producing various gypsum products can be met, and the application field of the phosphogypsum is widened;

(2) the building gypsum produced by the process has high content of semi-hydrated gypsum, good stability and high quality: the method comprises the following steps of removing free water and then removing crystal water by adopting a two-step method, wherein the whole process adopts an indirect heat exchange mode with steam as a heat source, and the steam is not directly contacted with raw materials, so that the product is not polluted, and the product quality is ensured;

(3) by adopting the process method, the development and utilization of the industrial byproduct gypsum such as phosphogypsum and the like can organically combine the chemical industry and the building material industry of the byproduct gypsum, realize the non-waste residue discharge of the industries such as phosphate fertilizer, phosphoric acid and the like, not only can avoid the secondary pollution problem caused by stacking, but also can change waste into valuable, promote the further development of the chemical industry in China, and have important practical significance for the economic construction and the environmental protection in China.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions will be clearly and completely described below with reference to the embodiments of the present invention. The following describes the embodiments of the present invention in detail with reference to specific examples.

Example 1

The invention relates to a method for preparing high-quality building gypsum by using phosphogypsum, which is industrial waste residue generated in the process of preparing phosphoric acid by reacting phosphorite with sulfuric acid in the production process of wet-process phosphoric acid, at present, the phosphogypsum is mostly treated in a stacking mode, occupies a large amount of land, and simultaneously, harmful components such as soluble P, soluble F and the like diffuse and permeate to the surrounding environment through a medium to form a secondary pollution environment.

(1) Conveying the phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, removing large-particle impurities, and then conveying the phosphogypsum slag into a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities;

(2) vacuum filtering, multiple spraying and water washing in a cleaning machine, and 3-5 times of filtering and spraying, so that the content of soluble phosphorus in the phosphogypsum is not more than 0.2 percent, and the content of soluble fluorine in the phosphogypsum is not more than 0.1 percent, the quality of the produced building gypsum is improved, the requirements of producing various gypsum products can be met, and the application field of the phosphogypsum is widened;

then adding a modifier to adjust the pH, wherein the modifier is any one of a calcium hydroxide solution or a sodium hydroxide solution, the adjusted pH value is between 5 and 7, and pumping to dry for later use;

(3) crushing the cleaned phosphogypsum raw material, wherein the particle size of the crushed raw material is less than 80 microns, and sending the crushed raw material into a drier for primary drying, wherein the drying temperature is 100 ℃, and the drying time is 10-12 minutes, and because the particle size of the crushed raw material is small and the surface area is increased, the subsequent drying efficiency can be improved, and the energy is saved;

(4) the dried phosphogypsum is finely ground, the particle size of the ground raw material is 5 microns, then the raw material is conveyed to a calcining furnace for calcining, the calcining temperature is 180 ℃, the calcining time is 6-8 minutes, the exchange between the ground raw material and hot steam is more sufficient, the phosphogypsum is more completely calcined, and the prepared building gypsum has high content of semi-hydrated gypsum, good stability and high quality;

(5) the calcined material is cooled and conveyed by a cooling discharge conveying mechanism, and then is subjected to powder selection after being cooled, and then enters a homogenizing warehouse for homogenization.

As a preferred scheme, the heat source used in the steps (3) and (4) is hot steam, the free water is removed firstly by adopting a two-step method, then the crystal water is removed, the whole process adopts an indirect heat exchange mode with the steam as the heat source, the steam is not directly contacted with the raw materials, the product is not polluted, and the product quality is ensured; meanwhile, the waste heat discharged from the calcining furnace is introduced into the dryer for cyclic utilization, so that the resource utilization of the phosphogypsum is realized, the energy is saved, the utilization rate of the fuel is greatly improved, and the adverse effect of the direct discharge of hot air on the environment is avoided.

By adopting the process method, the development and utilization of the industrial byproduct gypsum such as phosphogypsum and the like can organically combine the chemical industry and the building material industry of the byproduct gypsum, realize the non-waste residue discharge of the industries such as phosphate fertilizer, phosphoric acid and the like, not only can avoid the secondary pollution problem caused by stacking, but also can change waste into valuable, promote the further development of the chemical industry in China, and have important practical significance for the economic construction and the environmental protection in China.

Example 2

The invention relates to a method for preparing high-quality building gypsum by using phosphogypsum, which is industrial waste residue generated in the process of preparing phosphoric acid by reacting phosphorite with sulfuric acid in the production process of wet-process phosphoric acid, at present, the phosphogypsum is mostly treated in a stacking mode, occupies a large amount of land, and simultaneously, harmful components such as soluble P, soluble F and the like diffuse and permeate to the surrounding environment through a medium to form a secondary pollution environment.

(1) Conveying the phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, removing large-particle impurities, and then conveying the phosphogypsum slag into a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities;

(2) vacuum filtering, multiple spraying and water washing in a cleaning machine, and 3-5 times of filtering and spraying, so that the content of soluble phosphorus in the phosphogypsum is not more than 0.2 percent, and the content of soluble fluorine in the phosphogypsum is not more than 0.1 percent, the quality of the produced building gypsum is improved, the requirements of producing various gypsum products can be met, and the application field of the phosphogypsum is widened;

then adding a modifier to adjust the pH, wherein the modifier is any one of a calcium hydroxide solution or a sodium hydroxide solution, the adjusted pH value is between 5 and 7, and pumping to dry for later use;

(3) crushing the cleaned phosphogypsum raw material, wherein the particle size of the crushed raw material is less than 80 microns, and sending the crushed raw material into a drier for primary drying, wherein the drying temperature is 120 ℃, and the drying time is 8-10 minutes, and because the particle size of the crushed raw material is small and the surface area is increased, the subsequent drying efficiency can be improved, and the energy is saved;

(4) the dried phosphogypsum is finely ground, the particle size of the ground raw material is 30 microns, then the raw material is conveyed to a calcining furnace for calcining, the calcining temperature is 200 ℃, the calcining time is 3-5 minutes, the exchange between the ground raw material and hot steam is more sufficient, the phosphogypsum is more completely calcined, and the prepared building gypsum has high content of semi-hydrated gypsum, good stability and high quality;

(5) the calcined material is cooled and conveyed by a cooling discharge conveying mechanism, and then is subjected to powder selection after being cooled, and then enters a homogenizing warehouse for homogenization.

As a preferred scheme, the heat source used in the steps (3) and (4) is hot steam, the free water is removed firstly by adopting a two-step method, then the crystal water is removed, the whole process adopts an indirect heat exchange mode with the steam as the heat source, the steam is not directly contacted with the raw materials, the product is not polluted, and the product quality is ensured; meanwhile, the waste heat discharged from the calcining furnace is introduced into the dryer for cyclic utilization, so that the resource utilization of the phosphogypsum is realized, the energy is saved, the utilization rate of the fuel is greatly improved, and the adverse effect of the direct discharge of hot air on the environment is avoided.

By adopting the process method, the development and utilization of the industrial byproduct gypsum such as phosphogypsum and the like can organically combine the chemical industry and the building material industry of the byproduct gypsum, realize the non-waste residue discharge of the industries such as phosphate fertilizer, phosphoric acid and the like, not only can avoid the secondary pollution problem caused by stacking, but also can change waste into valuable, promote the further development of the chemical industry in China, and have important practical significance for the economic construction and the environmental protection in China.

Example 3

The invention relates to a method for preparing high-quality building gypsum by using phosphogypsum, which is industrial waste residue generated in the process of preparing phosphoric acid by reacting phosphorite with sulfuric acid in the production process of wet-process phosphoric acid, at present, the phosphogypsum is mostly treated in a stacking mode, occupies a large amount of land, and simultaneously, harmful components such as soluble P, soluble F and the like diffuse and permeate to the surrounding environment through a medium to form a secondary pollution environment.

(1) Conveying the phosphogypsum slag discharged from a chemical plant to a vibration separator for separation, removing large-particle impurities, and then conveying the phosphogypsum slag into a cleaning machine for primary washing by using industrial wastewater to remove mineral impurities;

(2) vacuum filtering, multiple spraying and water washing in a cleaning machine, and 3-5 times of filtering and spraying, so that the content of soluble phosphorus in the phosphogypsum is not more than 0.2 percent, and the content of soluble fluorine in the phosphogypsum is not more than 0.1 percent, the quality of the produced building gypsum is improved, the requirements of producing various gypsum products can be met, and the application field of the phosphogypsum is widened;

then adding a modifier to adjust the pH, wherein the modifier is any one of a calcium hydroxide solution or a sodium hydroxide solution, the adjusted pH value is between 5 and 7, and pumping to dry for later use;

(3) crushing the cleaned phosphogypsum raw material, wherein the particle size of the crushed raw material is less than 80 microns, and sending the crushed raw material into a drier for primary drying, wherein the drying temperature is 150 ℃, and the drying time is 5-7 minutes, and because the particle size of the crushed raw material is small and the surface area is increased, the subsequent drying efficiency can be improved, and the energy is saved;

(4) the dried phosphogypsum is finely ground, the particle size of the ground raw material is 60 microns, then the raw material is conveyed to a calcining furnace for calcining, the calcining temperature is 240 ℃, the calcining time is 2-4 minutes, the exchange between the ground raw material and hot steam is more sufficient, the phosphogypsum is more completely calcined, and the prepared building gypsum has high content of semi-hydrated gypsum, good stability and high quality;

(5) the calcined material is cooled and conveyed by a cooling discharge conveying mechanism, and then is subjected to powder selection after being cooled, and then enters a homogenizing warehouse for homogenization.

As a preferred scheme, the heat source used in the steps (3) and (4) is hot steam, the free water is removed firstly by adopting a two-step method, then the crystal water is removed, the whole process adopts an indirect heat exchange mode with the steam as the heat source, the steam is not directly contacted with the raw materials, the product is not polluted, and the product quality is ensured; meanwhile, the waste heat discharged from the calcining furnace is introduced into the dryer for cyclic utilization, so that the resource utilization of the phosphogypsum is realized, the energy is saved, the utilization rate of the fuel is greatly improved, and the adverse effect of the direct discharge of hot air on the environment is avoided.

By adopting the process method, the development and utilization of the industrial byproduct gypsum such as phosphogypsum and the like can organically combine the chemical industry and the building material industry of the byproduct gypsum, realize the non-waste residue discharge of the industries such as phosphate fertilizer, phosphoric acid and the like, not only can avoid the secondary pollution problem caused by stacking, but also can change waste into valuable, promote the further development of the chemical industry in China, and have important practical significance for the economic construction and the environmental protection in China.

In addition to the foregoing, the foregoing shows and describes the general principles, broad features and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.