阅读说明：本技术 一种用废硫酸生产硫酸钙的工艺 (Process for producing calcium sulfate by using waste sulfuric acid ) 是由 任杰 于 2020-12-01 设计创作，主要内容包括：本发明公开了一种用废硫酸生产硫酸钙的工艺,该工艺包括原料提取与处理、原料清洗、烘干脱水、废硫酸除杂脱色与稀释、硫酸钙制取和浆液过滤与烘干等步骤。本发明工艺流程简单,配方控制合理,制得的硫酸钙成品质量高,通过专业处理,能够达到水泥制造的使用标准,不仅可替代脱硫石膏,还可大幅降低水泥厂的石膏采购成本,通过新增一项废酸消化渠道,扩大了废酸处置量,增加了处置收益,解决了由于处置废酸形成的产物无法销售导致反向制约废酸处置能力发挥的问题,通过以处置废酸为目的的合成反应,有效解决了合成产物硫酸钙的去向,从而充分释放了废酸处置资质带来的经济效益,并且可循环利用,变废为宝,从而实现三方共赢。(The invention discloses a process for producing calcium sulfate by using waste sulfuric acid, which comprises the steps of raw material extraction and treatment, raw material cleaning, drying and dehydration, impurity removal, decoloration and dilution of the waste sulfuric acid, calcium sulfate preparation, slurry filtration and drying and the like. The invention has simple process flow and reasonable formula control, the prepared calcium sulfate finished product has high quality, can reach the use standard of cement manufacture through professional treatment, not only can replace desulfurized gypsum, but also can greatly reduce the gypsum purchase cost of a cement plant, enlarges the disposal quantity of waste acid by adding a waste acid digestion channel, increases the disposal income, solves the problem of reversely restricting the disposal capacity of the waste acid to play due to the fact that products formed by disposing the waste acid cannot be sold, effectively solves the destination of the synthetic product calcium sulfate through the synthetic reaction aiming at disposing the waste acid, fully releases the economic benefit caused by the disposal quality of the waste acid, can be recycled, changes waste into valuables, and realizes three-party win.)

1. A process for producing calcium sulfate by using waste sulfuric acid is characterized by comprising the following steps:

a: raw material extraction and treatment: crushing and grinding limestone to obtain a calcium carbonate material;

b: cleaning raw materials: b, putting the calcium carbonate material obtained in the step A into clear water for cleaning, and stirring the calcium carbonate material by stirring equipment in the cleaning process so as to remove dust and impurities attached to the surface of the calcium carbonate;

c: drying and dehydrating: c, heating and drying the calcium carbonate material obtained in the step B so as to remove residual moisture on the surface of the calcium carbonate material;

d: removing impurities, decoloring and diluting the waste sulfuric acid: adding activated carbon into the waste sulfuric acid solution so as to carry out decoloration and impurity removal on the waste sulfuric acid solution, and diluting the waste sulfuric acid solution after the decoloration and impurity removal of the waste sulfuric acid solution are finished;

e: preparing calcium sulfate: d, dripping the waste sulfuric acid solution obtained in the step D onto the calcium carbonate material obtained in the step C so as to enable the waste sulfuric acid and the calcium carbonate to generate a chemical reaction, thereby preparing calcium sulfate slurry, and stirring the calcium sulfate slurry by stirring equipment in the preparation process so as to enable the calcium carbonate material to be fully contacted with the waste sulfuric acid solution, thereby improving the reaction efficiency and effect;

f: filtering and drying the slurry: and E, filtering the calcium sulfate slurry obtained in the step E, and heating and drying to obtain dry calcium sulfate.

2. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and the grinding granularity of the calcium carbonate material in the step A is 500-1000 meshes.

3. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and B, the ratio of the calcium carbonate material to the clear water in the step B is 1: 10-30, and the cleaning time is 1-3 hours.

4. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and D, the molar concentration of the diluted waste sulfuric acid solution in the step D is 2-10 mol/L.

5. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and E, the mass ratio of the waste sulfuric acid solution to the calcium carbonate material in the step E is 5-20: 1.

6. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and E, rotating speed of the stirring equipment in the step E is 100-500 r/min, and stirring time is 30-150 min.

7. The process for producing calcium sulfate using spent sulfuric acid according to claim 1, wherein: and F, drying at the temperature of 80-130 ℃ for 2-4 h.

Technical Field

The invention relates to waste acid treatment, in particular to a process for producing calcium sulfate by using waste sulfuric acid.

Background

The domestic industry has no precedent for preparing calcium sulfate by specially using the reaction of sulfuric acid and calcium carbonate temporarily, because the chemical components of the gypsum are actually calcium sulfate, the gypsum exists widely in the natural world, and has wide distribution, low mining cost and no need of artificial synthesis. In addition, forced desulfurization and denitration of various chemical enterprises at present can produce the desulfurized gypsum in the desulfurization process, and the desulfurized gypsum has narrow application range and single use and is in a state of passing supply and demand in the market.

Because the product value formed by disposing the waste acid is low, the market capacity is small, the waste acid disposal amount of entrusters can not be completely digested, and a new project for digesting the waste acid to earn the disposal cost is urgently needed to be constructed, the process for producing the calcium sulfate by using the waste sulfuric acid is urgently needed to be invented.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a process for producing calcium sulfate by using waste sulfuric acid.

One of the purposes of the invention is realized by adopting the following technical scheme: a process for producing calcium sulfate by using waste sulfuric acid comprises the following steps:

a: raw material extraction and treatment: crushing and grinding limestone to obtain a calcium carbonate material;

b: cleaning raw materials: b, putting the calcium carbonate material obtained in the step A into clear water for cleaning, and stirring the calcium carbonate material by stirring equipment in the cleaning process so as to remove dust and impurities attached to the surface of the calcium carbonate;

c: drying and dehydrating: c, heating and drying the calcium carbonate material obtained in the step B so as to remove residual moisture on the surface of the calcium carbonate material;

d: removing impurities, decoloring and diluting the waste sulfuric acid: adding activated carbon into the waste sulfuric acid solution so as to carry out decoloration and impurity removal on the waste sulfuric acid solution, and diluting the waste sulfuric acid solution after the decoloration and impurity removal of the waste sulfuric acid solution are finished;

e: preparing calcium sulfate: d, dripping the waste sulfuric acid solution obtained in the step D onto the calcium carbonate material obtained in the step C so as to enable the waste sulfuric acid and the calcium carbonate to generate a chemical reaction, thereby preparing calcium sulfate slurry, and stirring the calcium sulfate slurry by stirring equipment in the preparation process so as to enable the calcium carbonate material to be fully contacted with the waste sulfuric acid solution, thereby improving the reaction efficiency and effect;

f: filtering and drying the slurry: and E, filtering the calcium sulfate slurry obtained in the step E, and heating and drying to obtain dry calcium sulfate.

Further, the grinding granularity of the calcium carbonate material in the step A is 500-1000 meshes.

Further, the ratio of the calcium carbonate material to the clear water in the step B is 1: 10-30, and the cleaning time is 1-3 hours.

Further, the molar concentration of the waste sulfuric acid solution diluted in the step D is 2-10 mol/L.

Further, the mass ratio of the waste sulfuric acid solution and the calcium carbonate material in the step E is 5-20: 1.

Furthermore, the rotating speed of the stirring equipment in the step E is 100-500 r/min, and the stirring time is 30-150 min.

Further, the drying temperature in the step F is 80-130 ℃, and the drying time is 2-4 hours.

Compared with the prior art, the invention has the beneficial effects that:

1. the method solves the destination of reaction products (or waste residues), effectively solves the destination of the synthetic product calcium sulfate through the synthetic reaction aiming at disposing the waste acid, fully releases the economic benefit brought by the disposal qualification of the waste acid, can be recycled, changes waste into valuable, and realizes the win-win of three parties;

2. by adding a waste acid digestion channel, the waste acid treatment capacity is enlarged, so that the treatment benefit is increased, and the problem that the waste acid treatment capacity is reversely restricted due to the fact that products formed by treating waste acid cannot be sold is effectively solved;

3. the process is simple, the formula is reasonably controlled, the quality of the prepared calcium sulfate finished product is high, the finished product can reach the use standard of cement manufacture through professional treatment, the performance of the finished product is superior to that of desulfurized gypsum, the finished product can replace the desulfurized gypsum, and the gypsum purchase cost of a cement plant can be greatly reduced.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a process flow diagram of the present embodiment.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example 1:

referring to fig. 1, a process for producing calcium sulfate from waste sulfuric acid includes the following steps:

a: raw material extraction and treatment: crushing and grinding limestone to obtain a calcium carbonate material, wherein the grinding granularity of the calcium carbonate material in the step A is 500 meshes;

b: cleaning raw materials: b, putting the calcium carbonate material obtained in the step A into clear water for cleaning, and stirring by using stirring equipment in the cleaning process so as to remove dust and impurities attached to the surface of the calcium carbonate, wherein the ratio of the calcium carbonate material to the clear water in the step B is 1:10, and the cleaning time is 1 h;

c: drying and dehydrating: c, heating and drying the calcium carbonate material obtained in the step B so as to remove residual moisture on the surface of the calcium carbonate material;

d: removing impurities, decoloring and diluting the waste sulfuric acid: adding activated carbon into the waste sulfuric acid solution so as to carry out decoloration and impurity removal on the waste sulfuric acid solution, and after the decoloration and impurity removal of the waste sulfuric acid solution are finished, diluting the waste sulfuric acid solution, wherein the molar concentration of the diluted waste sulfuric acid solution in the step D is 2 mol/L;

e: preparing calcium sulfate: d, dripping the waste sulfuric acid solution obtained in the step D onto the calcium carbonate material obtained in the step C so as to enable the waste sulfuric acid and calcium carbonate to perform chemical reaction to prepare calcium sulfate slurry, wherein the mass ratio of the waste sulfuric acid solution to the calcium carbonate material in the step E is 5:1, stirring is performed by stirring equipment in the preparation process so as to enable the calcium carbonate material to fully contact with the waste sulfuric acid solution, so that the reaction efficiency and effect are improved, the rotating speed of the stirring equipment in the step E is 100r/min, and the stirring time is 30 min;

f: filtering and drying the slurry: and D, filtering the calcium sulfate slurry obtained in the step E, and heating and drying to obtain dry calcium sulfate, wherein the drying temperature in the step F is 80 ℃, and the drying time is 2 hours.

Example 2:

referring to fig. 1, a process for producing calcium sulfate from waste sulfuric acid includes the following steps:

a: raw material extraction and treatment: crushing and grinding limestone to obtain a calcium carbonate material, wherein the grinding granularity of the calcium carbonate material in the step A is 750 meshes;

b: cleaning raw materials: b, putting the calcium carbonate material obtained in the step A into clear water for cleaning, and stirring by using stirring equipment in the cleaning process so as to remove dust and impurities attached to the surface of the calcium carbonate, wherein the ratio of the calcium carbonate material to the clear water in the step B is 1:20, and the cleaning time is 2 hours;

c: drying and dehydrating: c, heating and drying the calcium carbonate material obtained in the step B so as to remove residual moisture on the surface of the calcium carbonate material;

d: removing impurities, decoloring and diluting the waste sulfuric acid: adding activated carbon into the waste sulfuric acid solution so as to carry out decoloration and impurity removal on the waste sulfuric acid solution, and after the decoloration and impurity removal of the waste sulfuric acid solution are finished, diluting the waste sulfuric acid solution, wherein the molar concentration of the diluted waste sulfuric acid solution in the step D is 6 mol/L;

e: preparing calcium sulfate: d, dripping the waste sulfuric acid solution obtained in the step D onto the calcium carbonate material obtained in the step C so as to enable the waste sulfuric acid and calcium carbonate to perform chemical reaction to prepare calcium sulfate slurry, wherein the mass of the waste sulfuric acid solution and the calcium carbonate material in the step E is 12.5:1, stirring is performed by stirring equipment in the preparation process so as to enable the calcium carbonate material to fully contact with the waste sulfuric acid solution, so that the reaction efficiency and effect are improved, the rotating speed of the stirring equipment in the step E is 300r/min, and the stirring time is 90 min;

f: filtering and drying the slurry: and D, filtering the calcium sulfate slurry obtained in the step E, and heating and drying to obtain dry calcium sulfate, wherein the drying temperature in the step F is 105 ℃, and the drying time is 3 hours.

Example 3:

referring to fig. 1, a process for producing calcium sulfate from waste sulfuric acid includes the following steps:

a: raw material extraction and treatment: crushing and grinding limestone to obtain a calcium carbonate material, wherein the grinding granularity of the calcium carbonate material in the step A is 1000 meshes;

b: cleaning raw materials: b, putting the calcium carbonate material obtained in the step A into clear water for cleaning, and stirring by using stirring equipment in the cleaning process so as to remove dust and impurities attached to the surface of the calcium carbonate, wherein the ratio of the calcium carbonate material to the clear water in the step B is 1: 30, and the cleaning time is 3 hours;

c: drying and dehydrating: c, heating and drying the calcium carbonate material obtained in the step B so as to remove residual moisture on the surface of the calcium carbonate material;

d: removing impurities, decoloring and diluting the waste sulfuric acid: adding activated carbon into the waste sulfuric acid solution so as to carry out decoloration and impurity removal on the waste sulfuric acid solution, and after the decoloration and impurity removal of the waste sulfuric acid solution are finished, diluting the waste sulfuric acid solution, wherein the molar concentration of the diluted waste sulfuric acid solution in the step D is 10 mol/L;

e: preparing calcium sulfate: d, dripping the waste sulfuric acid solution obtained in the step D onto the calcium carbonate material obtained in the step C so as to enable the waste sulfuric acid and calcium carbonate to perform chemical reaction to prepare calcium sulfate slurry, wherein the mass ratio of the waste sulfuric acid solution to the calcium carbonate material in the step E is 20:1, stirring is performed by stirring equipment in the preparation process so as to enable the calcium carbonate material to fully contact with the waste sulfuric acid solution, so that the reaction efficiency and effect are improved, the rotating speed of the stirring equipment in the step E is 500r/min, and the stirring time is 150 min;

f: filtering and drying the slurry: and D, filtering the calcium sulfate slurry obtained in the step E, and heating and drying to obtain dry calcium sulfate, wherein the drying temperature in the step F is 130 ℃, and the drying time is 4 hours.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.