阅读说明：本技术 一种含卤石膏脱色制备新型钙镁质胶凝材料的工艺 (Process for preparing novel calcium-magnesium cementing material by decoloring halogen-containing gypsum ) 是由 王彦栋 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种含卤石膏脱色制备新型钙镁质胶凝材料的工艺,步骤如下：粉碎、酸浸、中和、固定游离卤素离子、煅烧、粉碎包装；本发明利用含卤石膏合成的含钙镁新型钙镁质胶凝材料,主要成分为β型半水石膏,环保无毒,并且由MgO与卤素离子反应生成的晶须结构,提高了本产品的机械强度,所以其一些性能优于传统的石膏胶凝材料,而且本发明的工艺简单、过程可操作性强、成本低廉,因此本发明可以解决大量含卤石膏堆积所产生的社会问题。(The invention discloses a process for preparing a novel calcium-magnesium cementing material by decoloring halogenous gypsum, which comprises the following steps: crushing, acid leaching, neutralizing, fixing free halogen ions, calcining, crushing and packaging; the novel calcium-magnesium containing cementing material synthesized by utilizing the halogen-containing gypsum, disclosed by the invention, has the main component of beta-type semi-hydrated gypsum, is environment-friendly and non-toxic, and the mechanical strength of the product is improved by a crystal whisker structure generated by the reaction of MgO and halogen ions, so that some performances of the novel calcium-magnesium containing cementing material are superior to those of the traditional gypsum cementing material.)

1. A process for preparing a novel calcium-magnesium cementing material by decoloring halogen-containing gypsum is characterized by comprising the following steps:

s1, crushing: drying the halogen-containing gypsum in the air or by a dryer, and then crushing the halogen-containing gypsum by a crusher;

s2, acid leaching: putting the crushed halogen-containing gypsum particles into a forced stirrer, starting the stirrer to stir, then adding sulfuric acid to mix, continuing to stir uniformly, and finally discharging, stacking and curing;

s3, neutralization: putting the material finally obtained in the step S2 into a forced stirrer for stirring, adding water into the material, uniformly mixing, then adding quicklime or dolomite and sulfuric acid for neutralization reaction, discharging after the reaction, stacking and curing to ensure that free acid in the material completely reacts;

s4, immobilized free halogen ion: putting the material finally obtained in the step S3 into a forced stirrer for stirring, adding light-burned magnesium oxide into the material, stirring for reaction, uniformly mixing, stacking and curing;

s5, calcining: putting the materials into a calcining furnace, calcining until the weight of the materials is constant, taking out the materials, and cooling to room temperature to obtain white blocky solid materials which are easy to break;

s6, crushing and packaging: and crushing the calcined material to obtain a finished product, and hermetically packaging the obtained finished product.

2. The process for preparing the novel calcium-magnesium binding material by decoloring the halogen-containing gypsum according to claim 1, wherein in the step S1, the halogen-containing gypsum is dried in a dryer at 100-110 ℃; the halogen-containing gypsum is crushed into particles with the particle size of less than 20 meshes.

3. The process for preparing a novel calcium-magnesium binding material by decoloring the halogenous gypsum according to claim 1, wherein the sulfuric acid in the step S2 is 98% industrial-grade concentrated sulfuric acid.

4. The process for preparing the novel calcium-magnesium binding material by decoloring the halogenous gypsum according to claim 1, wherein in the step S2, the mass ratio of the halogenous gypsum to the sulfuric acid is 5: 1; stirring for 10-30 min after the sulfuric acid is added; the material heat release temperature is between 80 and 90 ℃; stacking and curing for 2-5 hours.

5. The process for preparing the novel calcium-magnesium cementing material by decoloring the halogenous gypsum according to claim 1, wherein in the step S3, the mass ratio of the materials to the water is 3: 0.5-1.5; the curing time is 5-10 hours.

6. The process for preparing the novel calcium-magnesium cementing material by decoloring the halogenous gypsum according to claim 1, wherein in the step S4, the mass ratio of the material to the light-burned magnesium oxide is 10: 1-3, the stirring reaction is carried out for 30 minutes, and the stacking and curing are carried out for 3-5 hours.

7. The process for preparing the novel calcium-magnesium binding material by decoloring the halogen-containing gypsum according to claim 1, wherein in the step S5, the material is calcined at the temperature of 150-160 ℃ until the material has a constant weight.

8. The process for preparing a novel calcium-magnesium binding material by decoloring halogen-containing gypsum according to claim 1, wherein in the step S6, the calcined material is pulverized into 120-mesh powder.

Technical Field

The invention relates to a process for preparing a novel calcium-magnesium cementing material by decoloring halogenous gypsum.

Background

The halogen-containing gypsum is the main waste residue in the sea salt industry, the main component of the halogen-containing gypsum is calcium sulfate dihydrate, three large salt farms and countless small and medium-sized salt farms in China are located in coastal areas, a large amount of halogen-containing gypsum is discharged every year, most of the halogen-containing gypsum is randomly stacked, the occupied space is occupied, the surrounding sea area environment is polluted, and the limit is brought to the re-expansion of the salt farms. In addition, most of the soda plants in China are located in coastal areas, and they will contain a large amount of CaCl₂The wastewater is discharged into the sea through the salt field, which causes the displacement of the halogen-containing gypsum in the salt field to increase greatly. It is reported that only Shandong discharges nearly 15 million tons of halogen-containing gypsum waste residue per year, which corresponds to a medium-sized waste residueAnnual yield of gypsum mine; coastal areas are areas with faster economic development, and with the development of the building industry in China, the development and utilization of novel building materials are social problems to be solved urgently; compared with other developed countries, China has a certain gap in the development and utilization of gypsum, the development and utilization of natural gypsum have not yet formed a scale, and the utilization of chemical gypsum is just started. At present, all the gypsum decoloring technologies in China mostly mix broken gypsum with a large amount of water, add a pickling agent mixed by hydrochloric acid, oxalic acid, acetic acid and other acids, decolor, filter and wash. The process not only produces a large amount of waste water, but also is labor-consuming, time-consuming and energy-consuming.

Disclosure of Invention

Aiming at the defects of the prior art, the invention solves the problems that: provides a process for preparing the novel calcium-magnesium cementing material by decoloring the halogen-containing gypsum, which has low cost, energy conservation and emission reduction.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a process for preparing a novel calcium-magnesium cementing material by decoloring halogenous gypsum comprises the following steps:

s1, crushing: drying the halogen-containing gypsum in the air or by a dryer, and then crushing the halogen-containing gypsum by a crusher;

s2, acid leaching: putting the crushed halogen-containing gypsum particles into a forced stirrer, starting the stirrer to stir, then adding sulfuric acid to mix, continuing to stir uniformly, and finally discharging, stacking and curing;

s3, neutralization: putting the material finally obtained in the step S2 into a forced stirrer for stirring, adding water into the material, uniformly mixing, then adding quicklime or dolomite and sulfuric acid for neutralization reaction, discharging after the reaction, stacking and curing to ensure that free acid in the material completely reacts;

s4, immobilized free halogen ion: putting the material finally obtained in the step S3 into a forced stirrer for stirring, adding light-burned magnesium oxide into the material, stirring for reaction, uniformly mixing, stacking and curing;

s5, calcining: putting the materials into a calcining furnace, calcining until the weight of the materials is constant, taking out the materials, and cooling to room temperature to obtain white blocky solid materials which are easy to break;

s6, crushing and packaging: and crushing the calcined material to obtain a finished product, and hermetically packaging the obtained finished product.

Further, in the step S1, the halogen-containing gypsum is dried in a dryer at 100 to 110 ℃; the halogen-containing gypsum is crushed into particles with the particle size of less than 20 meshes.

Further, the sulfuric acid in the step S2 is 98% industrial-grade concentrated sulfuric acid.

Further, in the step S2, the mass ratio of the halogen-containing gypsum to the sulfuric acid is 5: 1; stirring for 10-30 min after the sulfuric acid is added; the material heat release temperature is between 80 and 90 ℃; stacking and curing for 2-5 hours.

Further, in the step S3, the mass ratio of the materials to the water is 3: 0.5-1.5; the curing time is 5-10 hours.

Further, in the step S4, the mass ratio of the materials to the light-burned magnesia is 10: 1-3, the materials are stirred to react for 30 minutes, and the materials are stacked and cured for 3-5 hours.

Further, in the step S5, the material is calcined at the temperature of 150-160 ℃ until the weight of the material is constant.

Further, in the step S6, the calcined material is pulverized into a powder of 120 mesh.

The invention has the following beneficial effects:

1. the novel calcium-magnesium containing cementing material synthesized by utilizing the halogen-containing gypsum, disclosed by the invention, has the main component of beta-type semi-hydrated gypsum, is environment-friendly and non-toxic, and the mechanical strength of the product is improved by a crystal whisker structure generated by the reaction of MgO and halogen ions, so that some performances of the novel calcium-magnesium containing cementing material are superior to those of the traditional gypsum cementing material.

2. The method does not need to wash and screen the halogen-containing gypsum in the production process, compared with the traditional gypsum decolorization process, the method improves the utilization rate of the halogen-containing gypsum to the maximum extent, does not discharge waste acid and waste water, does not cause secondary pollution, reasonably utilizes the reaction in the production process to release heat, and has lower energy consumption, so the method not only meets the requirement of developing novel building materials, but also plays a positive role in protecting the ecological environment.

3. The invention utilizes the dehydration property of concentrated sulfuric acid to dehydrate the halogen-containing gypsum, wherein the dehydration refers to the process of removing non-free water molecules by the concentrated sulfuric acid or removing oxyhydrogen elements in organic matters according to the composition ratio of oxyhydrogen atoms of water, after dehydration, the crystal structure is destroyed, and then the property of double salt and inorganic salt whisker can be formed by the magnesium oxide which is the main component in light-burned magnesium oxide, and halogen ions and other inorganic ions can be fixed, such as 5Mg (OH) are formed₂·MgCl₂·8H₂O and 3Mg (OH)₂·MgCl₂·8H₂The whiteness and strength of the material are improved, and the novel building material containing calcium and magnesium elements is prepared by calcining and crushing, so that the social problems that the halogenated gypsum is stacked in a large quantity, occupies space and can form secondary pollution are solved.

Drawings

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

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Example 1

As shown in figure 1, the process for preparing the novel calcium-magnesium cementing material by decoloring the halogenous gypsum comprises the following steps:

s1, crushing: drying the halogen-containing gypsum at 105 ℃, and then crushing the halogen-containing gypsum into particles with the particle size of less than 20 meshes by using a crusher.

S2, acid leaching: 1000Kg of crushed halogenous gypsum is put into a forced stirrer, the stirrer is started, 200Kg of sulfuric acid is added, the mixture is stirred for 20 minutes after the sulfuric acid is added, the temperature can reach 88 ℃ at most, the materials are discharged, and the materials are stacked and cured for 4 hours, so that the materials are gradually changed into light cyan from earthy yellow.

S3, neutralization: and (4) putting the material finally obtained in the step S2 into a forced stirrer, starting stirring, adding 400Kg of water into the material, gradually adding 143Kg of quicklime after uniform mixing, generating a large amount of heat in the reaction process, continuing stirring for 30 minutes after the quicklime is added, discharging, stacking and curing for 10 hours.

S4, immobilized free halogen ion: and (5) putting the materials obtained in the step S3 into a forced stirrer, starting stirring, adding 140Kg of light-burned magnesium oxide into the materials, stirring for 30 minutes, discharging and curing for 5 hours.

S5, calcining: the materials are put into a calcining furnace and calcined at 155 ℃ until the weight of the materials is constant, and the materials are taken out and cooled to room temperature.

S6, crushing and packaging: and crushing the calcined material into 120-mesh powder to obtain a finished product, and hermetically packaging the obtained finished product.

Example 2

As shown in figure 1, the process for preparing the novel calcium-magnesium cementing material by decoloring the halogenous gypsum comprises the following steps:

s1, crushing: drying the halogen-containing gypsum at 105 ℃, and then crushing the halogen-containing gypsum into particles with the particle size of less than 20 meshes by using a crusher.

S2, acid leaching: putting 500Kg of crushed halogenous gypsum into a forced stirrer, starting the stirrer, adding 100Kg of sulfuric acid, stirring for 15 minutes after the acid is added, and enabling the temperature to be up to 84 ℃; the mixture is piled and aged for 3 hours, and the material gradually changes from earthy yellow to light cyan.

S3, neutralization: and (3) putting the materials obtained in the step S2 into a forced stirrer, starting stirring, adding 170Kg of water into the materials, gradually adding 111Kg of dolomite after uniform mixing, generating a large amount of heat and carbon dioxide in the reaction process, continuously stirring for 30 minutes after the addition of the dolomite is finished, discharging, stacking and curing for 8 hours.

S4, immobilized free halogen ion: and (4) putting the materials obtained in the step S3 into a forced stirrer, starting stirring, adding 125Kg of light-burned magnesium oxide into the materials, stirring for 30 minutes, uniformly mixing, discharging and curing for 4 hours.

S5, calcining: the materials are put into a calcining furnace and calcined at 150 ℃ until the weight of the materials is constant, and the materials are taken out and cooled to room temperature.

S6, crushing and packaging: and crushing the calcined material into 120-mesh powder to obtain a finished product, and hermetically packaging the obtained finished product.

Example 3

As shown in figure 1, the process for preparing the novel calcium-magnesium cementing material by decoloring the halogenous gypsum comprises the following steps:

s1, crushing: drying the halogen-containing gypsum at 105 ℃, and then crushing the halogen-containing gypsum into particles with the particle size of less than 20 meshes by using a crusher.

S2, acid leaching: 500Kg of crushed halogenous gypsum is put into a forced stirrer, the stirrer is started, 100Kg of sulfuric acid is added, after the acid is added, the mixture is stirred for 15 minutes and uniformly mixed, and the temperature can reach 83 ℃ at most. Discharging, stacking and curing for 3 hours, and gradually changing the material from earthy yellow to light cyan.

S3, neutralization: and (3) putting the materials obtained in the step S2 into a forced stirrer, starting stirring, adding 200Kg of water into the materials, gradually adding 71Kg of quicklime after uniform mixing, generating a large amount of heat in the reaction process, continuously stirring for 30 minutes after the quicklime is added, discharging, stacking and curing for 6 hours.

S4, immobilized free halogen ion: and (4) putting the materials obtained in the step S3 into a forced stirrer, starting stirring, adding 125Kg of light-burned magnesium oxide into the materials, stirring for 30 minutes, discharging and curing for 4 hours.

S5, calcining: the materials are put into a calcining furnace and calcined at 150 ℃ until the weight of the materials is constant, and the materials are taken out and cooled to room temperature.

S6, crushing and packaging: and crushing the calcined material into 120-mesh powder to obtain a finished product, and hermetically packaging the obtained finished product.

The total calcium oxide content of the halogen-containing gypsum used in the above three examples was 28.67%; the calcium oxide content of the used quicklime is 79.39 percent; the content of magnesium oxide in the used light-burned magnesium oxide is 91.72%; the dolomite used has a total calcium oxide content of 30.31% and a total magnesium oxide content of 15.24%.

The properties of the materials prepared in the examples were measured as follows.

The data in the table show that the novel calcium and magnesium-containing building material produced by the process in the scheme of the invention can be compared favorably with the traditional gypsum cementing material, and some performances are superior to those of the traditional gypsum cementing building material.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.