Preparation method and application of manganese gypsum

Abstract

The application discloses a preparation method and application of manganese gypsum, and the method is characterized by the following steps: uniformly mixing manganese sulfate residue, red mud, desulfurization ash and water, stirring into slurry, and aging for a period of time to obtain the product manganese gypsum which can be used as a cement retarder. In the application, the alkaline solid waste red mud and desulfurization ash are added to the manganese residue, and the calcium sulfite in the desulfurization ash is oxidized in the mixing process, thereby modifying the manganese residue and improving the sulfur content in the manganese gypsum and the retarding effect. The preparation method is simple, the manganese residue disposal amount is large, the manganese residue is innovatively prepared into the retarder required by cement production, and the preparation method does not need high-temperature treatment and does not consume electric energy, so that the energy consumption is reduced. Finally, the difficult-to-handle manganese residue, red mud and desulfurization ash are solidified and treated to prepare the retarder required by cement production, the manganese residue is converted into a resource which can be directly used in the building material industry, the resource utilization of the waste is realized, the application is simple and practical, and the purpose of reducing cost and increasing efficiency is achieved.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a method for preparing manganese gypsum and its application. Background Technology

[0002] In related technologies, producing 1 ton of metallic manganese may generate 8-10 tons of manganese slag. Manganese slag contains a large amount of soluble salt compounds, has a complex composition, and improper disposal can easily cause significant environmental risks. Currently, manganese slag is mainly disposed of through landfill, which not only occupies a large amount of land and incurs high disposal costs, but also causes serious environmental pollution. Red mud is an alkaline solid waste discharged during alumina production. Its main components are iron oxide, silicon dioxide, calcium oxide, aluminum oxide, sodium oxide, and titanium dioxide, as well as certain amounts of rare elements and trace amounts of radioactive elements. Currently, producing 1 ton of alumina may generate 1.5-2 tons of red mud, and a large amount of red mud is disposed of through landfill or stockpiling. Due to the high alkalinity and large quantity of red mud, traditional treatment methods cause serious pollution to surrounding water bodies, air, and soil.

[0003] Currently, besides landfilling or direct stockpiling, most manganese slag is treated by converting it into usable resources for the cement and other building materials industries. However, manganese slag contains many impurities, which limits the application of its final products; moreover, the disposal process requires the consumption of reagents and electricity, and large-scale disposal will result in huge energy consumption and reagent input; in addition, the process is cumbersome, poses safety and environmental risks, and easily leads to a waste of human and material resources, which further restricts its widespread application.

[0004] Therefore, solving the problems of high energy consumption, complicated procedures, and limited application of end products in the treatment of manganese slag is of great environmental significance and production value. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for preparing manganese gypsum and its application, aiming to provide a method for directly converting manganese slag into manganese gypsum—a resource usable in the building materials industry—and solving the current problems in manganese slag treatment.

[0006] In a first aspect, the present invention provides a method for preparing manganese gypsum, comprising the steps of:

[0007] S1. Mix manganese slag, red mud, desulfurization ash and water evenly according to the predetermined ratio and stir into a slurry;

[0008] S2. After aging the slurry for a predetermined time, the manganese gypsum is obtained.

[0009] The method for preparing manganese gypsum according to embodiments of the present invention has at least the following beneficial effects: The method for preparing manganese gypsum provided by the present invention involves adding alkaline solid waste—red mud and desulfurization ash—to manganese slag. During the mixing process, the calcium sulfite in the desulfurization ash is oxidized, modifying the manganese slag and increasing the sulfur content and retarding effect in the manganese gypsum. The preparation method of the present invention is simple, allows for the disposal of large quantities of manganese slag, and can alleviate environmental pressure. Moreover, the preparation method of the present invention does not require high-temperature treatment or consume electricity, greatly saving resources, reducing energy consumption, and further reducing costs. Ultimately, the present invention solidifies the difficult-to-treat manganese slag, red mud, and desulfurization ash to prepare a retarder suitable for cement production, converting manganese slag into a resource that can be directly utilized by the building materials industry, realizing the resource utilization of waste, and is simple and practical. The present invention not only achieves efficient utilization of manganese slag, improves the production efficiency of cement enterprises, and reduces the environmental and economic pressure on the manganese industry, but also offers an economical and practical solution with low cost, convenient operation, and high safety, greatly reducing the environmental and safety risks for enterprises and bringing good social and economic benefits.

[0010] In some preferred embodiments of the present invention, the mass fractions of the manganese slag, red mud, desulfurization ash, and water are as follows:

[0011]

[0012] In some more preferred embodiments of the present invention, the mass ratio of the manganese slag, red mud, desulfurization ash, and water is 7:0.5:0.5:2. For example, the mass parts of the manganese slag, red mud, desulfurization ash, and water are 70, 5, 5, and 20 parts, respectively.

[0013] In some preferred embodiments of the present invention, the manganese slag is selected from manganese sulfate slag.

[0014] In some preferred embodiments of the present invention, the desulfurization ash comprises, by mass percentage: 65%–70% calcium sulfate, 5%–10% calcium sulfite, 20%–25% calcium hydroxide, and 0%–10% impurities. The impurities are selected from one or more of calcite and microcline.

[0015] More preferably, the desulfurization ash comes from solid waste generated during desulfurization in glass factories, and its main components are 65% calcium sulfate, 10% calcium sulfite, 20% calcium hydroxide, and 5% impurities (by mass). The main active component in cement retarder is calcium sulfate dihydrate. In this invention, the solid waste generated during glass factory desulfurization is mixed with manganese sulfate slag and red mud, and then aged. This process converts the calcium sulfate into calcium sulfate dihydrate, the effective component of the retarder, thus improving the retarding effect. Furthermore, the use of desulfurization ash to capture carbon dioxide can be extended to the cement industry, showing broad application prospects in solving environmental problems faced by the building materials industry.

[0016] Manganese slag contains a certain amount of ammonia nitrogen, posing environmental risks when directly applied industrially. While existing technologies, such as high-pressure rinsing with anolyte and high-pressure filtration, suffer from low product yields and high energy consumption, limiting large-scale application, this invention addresses these shortcomings. By studying, analyzing, and comparing the characteristics of electrolytic manganese slag, and considering the high calcium hydroxide content in desulfurization ash from glass factories, this invention proposes a method for preparing manganese gypsum for cement production. This method overcomes the waste of manpower and resources and high costs associated with conventional disposal methods. By adding alkaline solid waste red mud and high-calcium desulfurization ash, the calcium sulfite in the desulfurization ash is oxidized, modifying the manganese sulfate slag and increasing the sulfur content and retarding effect of the manganese gypsum. The method is convenient and safe, reducing environmental and safety risks for enterprises. It eliminates the need for high-temperature treatment and electricity consumption, significantly saving resources, reducing energy consumption, and further lowering costs. This method enables efficient utilization of manganese sulfate slag, improves the production efficiency of cement enterprises, alleviates the environmental and economic pressures on the manganese industry, and is economical, practical, and cost-effective.

[0017] In some preferred embodiments of the present invention, before step S1, the step of crushing the manganese slag to a particle size of less than 5 mm is included.

[0018] In some preferred embodiments of the present invention, in step S2, the slurry is aged for 5-10 days to obtain the manganese gypsum. More preferably, the slurry is aged for 7 days.

[0019] In a second aspect, the present invention provides manganese gypsum prepared by the above-described method.

[0020] In some preferred embodiments of the present invention, the raw materials of the manganese gypsum include 60-70 parts manganese slag, 5-10 parts red mud, 5-10 parts desulfurization ash, and 15-25 parts water by mass.

[0021] More preferably, the manganese gypsum comprises 70 parts manganese slag, 5 parts red mud, 5 parts desulfurization ash, and 20 parts water by weight.

[0022] The manganese gypsum obtained according to the embodiments of the present invention has at least the following beneficial effects: the manganese gypsum is obtained by solidification treatment of difficult-to-treat manganese sulfate slag, red mud, and desulfurization ash, and is suitable as a retarder required for cement production, realizing the resource utilization of waste and bringing good social and economic benefits; at the same time, by adding alkaline solid waste red mud and high-calcium desulfurization ash to oxidize calcium sulfite in desulfurization ash and modify manganese sulfate slag, the sulfur content and retarding effect in manganese gypsum are improved.

[0023] In a third aspect, the present invention proposes the application of the above-mentioned manganese gypsum as a cement retarder.

[0024] In the cement production process, natural gypsum was initially used as a cement retarder. However, with the increasing demand for retarders, natural gypsum, as a natural non-renewable resource, can no longer meet the needs of the cement industry. Therefore, researching how to modify environmentally polluting solid waste manganese sulfate slag into manganese gypsum for use as a retarder in cement production is of great significance for alleviating environmental pressure and reducing production costs. The manganese gypsum produced by this invention can be used in cement production. A 5000t / d cement production line can consume 30,000 tons of manganese slag annually, showing broad prospects and significant advantages.

[0025] In some preferred embodiments of the present invention, the manganese gypsum is added to the cement at a mass percentage of 0.65% to 5.0%.

[0026] More preferably, the manganese gypsum is added to the cement at a mass percentage of approximately 1.8%.

[0027] In a fourth aspect, the present invention provides a cement in which the above-mentioned manganese gypsum is doped, wherein the manganese gypsum is doped in the cement at a mass percentage of 0.65% to 5.0%.

[0028] The cement obtained according to the embodiments of the present invention has at least the following beneficial effects: the cement is doped with manganese gypsum prepared by modifying solid waste manganese sulfate slag, which can act as a retarder, effectively reducing cement production costs and alleviating environmental pressure. Detailed Implementation

[0029] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0030] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] Unless otherwise specified in the following examples, the techniques or conditions described in the literature in this field or in accordance with the product instructions shall apply. All reagents or instruments without a specified manufacturer are commercially available conventional products.

[0032] Examples 1-3

[0033] Examples 1-3 are examples of manganese gypsum preparation, and the raw material proportions are shown in Table 1. The raw material proportions are by mass percentage; the manganese sulfate slag comes from industrial waste discharged by a certain enterprise, the red mud comes from an electrolytic aluminum enterprise, and the desulfurization ash comes from a glass enterprise. Its composition is 65% calcium sulfate, 10% calcium sulfite, 20% calcium hydroxide, and 5% impurities. The above raw materials are crushed to a particle size of 0-5 mm using a crusher, then stirred and mixed evenly. The resulting slurry is then piled up and aged for one week to obtain manganese gypsum.

[0034] Table 1

[0035] Manganese sulfate residue (%) Desulfurization ash (%) Red mud (%) water(%) Example 1 60 10 10 20 Example 2 65 8 7 20 Example 3 70 5 5 20

[0036] Example 4

[0037] A small-scale grinding test was conducted using the manganese gypsum prepared in Example 3 to determine the dosage of manganese gypsum in cement. The mix proportions for the small-scale grinding test of manganese gypsum are shown in Table 2. The raw material proportions are by mass percentage; other raw materials and equipment used in the table are conventional materials and equipment in the field.

[0038] Table 2

[0039]

[0040] The physical test results of the small grinding test are shown in Table 3.

[0041]

[0042] Therefore, the manganese gypsum prepared in the embodiments of the present invention can meet the retarding requirements of industrial cement and improve the flexural strength and 3-day compressive strength of cement. Thus, the method for preparing manganese gypsum by alkalizing and modifying manganese sulfate slag according to the present invention can be used in cement enterprises for the co-processing of manganese sulfate slag, and the product can be used as a retarder for cement production, possessing certain practical application value.

[0043] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A method for preparing manganese gypsum, characterized in that, Including the following steps: According to the predetermined ratio, manganese slag, red mud, desulfurization ash and water are mixed evenly and stirred into a slurry; After aging the slurry for 5-10 days, the manganese gypsum is obtained. The mass fractions of the manganese slag, red mud, desulfurization ash, and water are as follows: 60-70 parts of manganese slag; 5-10 parts red mud; 5-10 parts of desulfurization ash; 15-25 parts water; The manganese slag is selected from manganese sulfate slag; The desulfurization ash comprises, by mass percentage: 65%–70% calcium sulfate, 5%–10% calcium sulfite, 20%–25% calcium hydroxide, and 0%–10% impurities.

2. The method for preparing manganese gypsum according to claim 1, characterized in that, Before mixing the manganese slag, red mud, desulfurization ash, and water evenly, the process also includes the step of crushing the manganese slag to a particle size of less than 5 mm.

3. Manganese gypsum prepared by the method of any one of claims 1-2.

4. An application of manganese gypsum as described in claim 3 as a cement retarder.

5. The application according to claim 4, characterized in that, The manganese gypsum is added to the cement at a mass percentage of 0.65% to 5.0%.

6. A type of cement, characterized in that, The cement is doped with manganese gypsum as described in claim 3, wherein the mass percentage of manganese gypsum in the cement is 0.65% to 5.0%.

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