Method for resourceful treatment of bagasse white mud and electrolytic manganese residue and application thereof

Abstract

The application provides a resource processing method and application of bagasse white mud and electrolytic manganese residue, and relates to the technical field of waste resource. Specifically, slurry containing bagasse white mud and electrolytic manganese residue after crushing treatment is aged to obtain a manganese white mud coagulant. The application simultaneously recycles and processes the bagasse white mud and the electrolytic manganese residue and resources the bagasse white mud and the electrolytic manganese residue through a simple and feasible process route at a low cost of energy, additional raw materials and manpower, and a high-value coagulant product is obtained, the harmless treatment route of the bagasse white mud and the electrolytic manganese residue is effectively widened, the defects of waste of manpower and material resources and high cost caused by conventional treatment methods of the two solid wastes are overcome, and the application has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of waste resource utilization technology, and more specifically, to a method and application for the resource utilization of bagasse mud and electrolytic manganese slag. Background Technology

[0002] Bagasse white mud is a solid waste generated from sugarcane bagasse pulping and papermaking. It is a molten substance obtained from the extraction, evaporation, concentration, and alkali furnace combustion of black liquor during the papermaking process. This molten substance is then dissolved in water and subjected to a causticization reaction to produce a white precipitate, primarily composed of calcium carbonate and calcium hydroxide. Due to limitations such as insufficient technological maturity or high processing costs, most papermaking white mud from these enterprises still relies on landfilling or stockpiling. This is because even with separation and purification processes to collect calcium carbonate and calcium hydroxide, the market value of the collected products is low. Therefore, bagasse white mud is currently difficult to recycle and is generally disposed of through stockpiling or landfilling; however, this not only leads to resource waste but also causes environmental pollution. With the increasing stockpiles of papermaking white mud from enterprises and the continuously rising requirements for ecological and environmental protection, the disposal of papermaking white mud has become a key factor restricting the green development of pulp and paper enterprises.

[0003] Patent CN115724470A discloses a method for purifying manganese sulfate solution. The method involves adding modified bentonite and bagasse mud to the manganese sulfate solution, stirring and reacting, filtering to obtain a primary purified solution with COD removal; adding manganese fluoride to the primary purified solution, filtering to obtain a secondary purified solution with calcium and magnesium ions removed; and adding aluminum sulfate to the secondary purified solution, filtering to obtain a tertiary purified solution with fluoride ions removed. This invention utilizes bagasse mud to adjust the pH, maintaining the structure of the modified bentonite and improving the COD removal rate through reheat acidification of the modified bentonite. However, considering the consumption of bagasse mud, this method requires the use of thermally acidified modified bentonite, which would consume significant energy in large-scale processing. The process also requires manganese fluoride and aluminum sulfate, making the steps cumbersome. Furthermore, the method for harmlessly disposing of the final purified filtrate and waste residue is not clearly defined, making it difficult to widely apply to the treatment of bagasse mud.

[0004] Electrolytic manganese slag is a major byproduct of manganese refining. It appears as a powdery or fine granular solid, black in color, and its main component is calcium sulfate. Producing 1 ton of electrolytic manganese generates 8-12 tons of electrolytic manganese slag; simultaneously, as the grade of manganese ore decreases sharply, the amount of slag produced from electrolytic manganese is increasing. Currently, electrolytic manganese slag is mainly disposed of through dry open-air stockpiling. However, this method not only wastes a large amount of land resources but also causes soil acidification, damages soil structure, and biodiversity. Furthermore, many manganese slag stockpiles have inadequate or no seepage prevention measures, allowing soluble heavy metal ions and pollutants such as ammonia nitrogen in the slag to be washed into rivers or seep into the ground with rainwater, causing pollution of soil, groundwater, and surface water. Moreover, manganese slag in open-air stockpiles, exposed to sun and wind for many years, gradually enters the air with air currents, exacerbating air pollution.

[0005] In summary, the environmental pollution caused by bagasse white mud and electrolytic manganese slag has become a significant social problem. If a simple, practical, and low-cost method could be designed to directly convert all of these materials into usable resources, it would be of great significance for enterprises to reduce costs and increase efficiency, as well as for improving social benefits. Therefore, this invention is proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide a method for the resource-based treatment of bagasse white mud and electrolytic manganese slag, thereby enabling the simultaneous recycling and resource utilization of both bagasse white mud and electrolytic manganese slag, effectively broadening the harmless treatment pathways for bagasse white mud and electrolytic manganese slag.

[0007] The second objective of this invention is to provide a cement setting regulator that has the advantages of low cost and high setting regulation effect, while its preparation method is simple and inexpensive and has good workability.

[0008] A third object of the present invention is to provide the use of the aforementioned cement setting regulator in the field of concrete.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] A method for the resource utilization of bagasse mud and electrolytic manganese slag includes the following steps:

[0011] A slurry containing bagasse mud and crushed electrolytic manganese slag is aged to obtain a manganese mud coagulant.

[0012] A cement setting regulator, comprising the manganese white mud setting regulator prepared by the resource-based treatment method of bagasse white mud and electrolytic manganese slag.

[0013] The use of the aforementioned cement setting regulator in the field of concrete.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention analyzes and designs the physicochemical properties of bagasse white mud and electrolytic manganese slag, and combines the characteristics of building material enterprises using gypsum for setting regulation. It proposes a method for preparing manganese white mud setting regulator by resource utilization of bagasse white mud and electrolytic manganese slag to overcome the waste of manpower and material resources and high cost caused by conventional treatment methods.

[0016] Specifically, this invention utilizes alkaline bagasse mud to neutralize the acid in electrolytic manganese slag. Through aging, the electrolytic manganese slag is further modified and other impurities are solidified, improving the retarding effect of the manganese mud setting regulator. The method is simple, convenient to operate, and highly safe, thereby reducing the environmental and safety risks for enterprises. Furthermore, the aging treatment converts anhydrous calcium sulfate and / or calcium sulfite in the electrolytic manganese slag into calcium sulfate dihydrate, which is its main component for use as a setting regulator in cement. This reduces cement companies' dependence on conventional setting regulators (desulfurized gypsum, phosphogypsum, natural gypsum, etc.) and production costs while disposing of solid waste; effectively reducing cement companies' production costs while alleviating the environmental and economic pressures on the paper and electrolytic manganese industries.

[0017] This invention modifies and combines two inexpensive and difficult-to-treat wastes to achieve the economicalization of solid waste. It has a positive promoting effect and very broad application prospects in solving the environmental pressures and improving economic benefits faced by the building materials industry. Specifically, on the one hand, the manganese white mud setting regulator of this invention can be added at a maximum dosage of 3% in cement production, which can reduce the amount of desulfurized gypsum by 3%. Taking a 5000t / d production line as an example, it can reduce the amount of desulfurized gypsum by 60,000 tons per year. Based on a desulfurized gypsum price of 30 yuan / ton, this translates to an annual saving of 1.8 million yuan in setting regulator costs. On the other hand, after adding 3% manganese white mud setting regulator, the cement strength increases by 1MPa. Based on experience, this can increase the admixture dosage by 1% and reduce the clinker dosage by 1%. Based on a clinker cost of 180 yuan / ton, this can reduce clinker costs by 1.5 million tons * 180 yuan / ton * 1% = 2.7 million yuan. The two aspects combined can generate direct economic benefits of approximately 4.5 million yuan per year, providing very direct economic benefits. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] The first aspect of the present invention is to provide a method for the resource-based treatment of bagasse white mud and electrolytic manganese slag.

[0020] While existing processes can process bagasse white mud separately, the market value of the calcium compounds obtained through resource recovery is very low, failing to cover the cost of resource recovery. If bagasse white mud is used as a filler or raw material for other calcium-based materials, the pH of the bagasse white mud needs to be adjusted, its modified bentonite structure needs to be stabilized, and it needs to undergo thermal acidification treatment. Large-scale disposal consumes a lot of energy, and the amount of bagasse white mud consumed is relatively small. Therefore, it is difficult to achieve widespread application and can only be disposed of through landfill or dumping.

[0021] For electrolytic manganese slag, due to its high impurity content, ion purification agents are required to remove impurities during separate resource utilization. For example, for high calcium and magnesium ion content, ion purification agents such as manganese fluoride and aluminum sulfate are required. Moreover, the purification agents will have a certain impact on the application of the final product. In addition, the treatment process consumes reagents and heat energy, the steps are cumbersome, and there are safety and environmental risks. This does not conform to the development trend of dual carbon targets and is likely to cause a waste of human and material resources, thus limiting its further promotion and application.

[0022] Therefore, the present invention aims to provide a resource-based treatment method for bagasse white mud and electrolytic manganese slag, with the intention of forming a product with certain market value through a simple process route with lower energy, additional raw material and labor costs, so as to provide an effective and scalable treatment path for bagasse white mud and electrolytic manganese slag.

[0023] The preparation method mainly includes the following steps: aging a slurry containing bagasse white mud and crushed electrolytic manganese slag to obtain a manganese white mud coagulant.

[0024] The bagasse white mud in this invention is a waste product generated during the pulping and papermaking process of sugarcane bagasse. Its main components include calcium carbonate and calcium hydroxide, with a small amount of bagasse. It appears as a white, muddy substance, hence the name bagasse white mud. It is worth noting that the bagasse white mud obtained through the causticization reaction during papermaking contains a certain amount of fine sugarcane fiber, which can play a role in toughening and strengthening, thus improving cement strength. Simultaneously, the calcium carbonate particles in the bagasse white mud are extremely fine, and based on the theory of close packing, they can act as fillers in the cement, further contributing to improved cement strength.

[0025] In a preferred embodiment, the bagasse white mud further includes pretreatment to reduce its moisture content; in some more preferred embodiments, the pretreatment includes either sun drying or solid-liquid separation. In some optional embodiments, for cost reasons, sun drying in a sun-supported shed is preferred. By using a shed constructed with transparent shade panels, sunlight can pass through while rainwater cannot, ensuring effective evaporation of moisture from the bagasse white mud through sunlight and the enclosed shed environment; for efficiency reasons, pressure filtration is preferred to avoid the long time required for sun drying.

[0026] As a more preferred embodiment, the initial material of the bagasse white mud typically has a moisture content of ≥70%, but it is understood that this moisture content value is strongly affected by factors such as the source of the material, storage and transportation time, and stacking environment; the moisture content of the bagasse white mud after the pretreatment is 5% to 20%.

[0027] In a preferred embodiment, the particle size of the bagasse white mud is 0.05 mm to 0.5 mm.

[0028] The electrolytic manganese slag in this invention is the waste residue discharged during the electrolytic preparation of metallic manganese. Since electrolytic manganese is usually produced using manganese ore as raw material, after grinding, acidification, oxidation, neutralization and electrolytic extraction of metallic manganese, the electrolytic manganese slag is a weakly acidic industrial waste residue containing dihydrate gypsum, and also contains high concentrations of sulfate, ammonia nitrogen and manganese ions, as well as heavy metal ions such as selenium, lead and nickel from the ore raw material.

[0029] In a preferred embodiment, the particle size of the electrolytic manganese slag after the crushing treatment is ≤10mm.

[0030] As a preferred embodiment, the crushing process includes, but is not limited to, mechanical crushing, shearing crushing, grinding, etc. Those skilled in the art can select equipment such as jaw crushers, hammer crushers, and ball mills to implement the process according to the actual situation.

[0031] In one preferred embodiment, the electrolytic manganese slag further includes pretreatment to reduce the moisture content of the bagasse white mud; the specific implementation method here has the same selection range as the bagasse white mud method described above, so it will not be repeated here.

[0032] In a more preferred embodiment, the moisture content of the electrolytic manganese slag after the pretreatment is 5% to 10%, including but not limited to any one or any two of the following values: 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, and 10%.

[0033] In a preferred embodiment, the electrolytic manganese slag further includes pretreatment, which includes neutralizing the electrolytic manganese slag to avoid the electrolytic manganese slag having strong acidity that could negatively affect subsequent aging, or causing interference with the subsequent aging material composition due to excessive acidity.

[0034] In a more preferred embodiment, the neutralization agent includes soda lime; in some more preferred embodiments, the pH of the electrolytic manganese slag after neutralization is 7 to 8, including but not limited to any one or any two of 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, and 8.

[0035] It is understood that the above-mentioned pretreatment methods for bagasse white mud and electrolytic manganese slag provided in this invention are, according to conventional understanding in the art, performed before the preparation method of this invention, that is: the pretreated bagasse white mud and the pretreated electrolytic manganese slag are mixed to form a slurry and aged to obtain the manganese white mud coagulant.

[0036] In a preferred embodiment, the slurry comprises bagasse mud, electrolytic manganese slag, and water, with a mass ratio of (1-3):(6-8):1. In some optional embodiments, the mass ratio includes, but is not limited to, any one of 1:6:1, 1:7:1, 1:8:1, 2:6:1, 2:7:1, 2:8:1, 3:6:1, 3:7:1, and 3:8:1; more preferably, 2:7:1 is selected.

[0037] As a more preferred embodiment, tap water can be used, which has good feasibility and convenience; and the trace ions or impurities in tap water will not have any impact on the performance of the manganese white mud coagulant of the present invention.

[0038] In a preferred embodiment, the slurry further includes a modifier for regulating the aging process or enhancing the performance of the manganese white mud setting agent.

[0039] In a more preferred embodiment, the modifier includes bagasse white mud wastewater, which is a liquid waste product obtained from the solid-liquid separation of the raw material of bagasse white mud during pretreatment. This wastewater is alkaline and can promote aging. In some optional embodiments, the amount of bagasse white mud wastewater added is 0.1% to 3% of the mass of the slurry.

[0040] In a more preferred embodiment, the modifier includes desulfurization ash from a float glass plant, a solid waste generated during flue gas desulfurization in float glass production. Its main components are calcium sulfite, calcium sulfate, and small amounts of calcium carbonate and calcium hydroxide, which can enhance the setting effect of the manganese mud setting agent. In some optional embodiments, the amount of desulfurization ash added is 0.01% to 1% of the mass of the slurry.

[0041] In a more preferred embodiment, the modifier includes sugarcane fiber, which can be replaced with other fibers, etc. However, considering that one of the main processing targets of this invention is sugarcane white mud, sugarcane fiber is the preferred fiber choice based on raw material source and cost considerations, as it can effectively enhance the cement strength after the application of the manganese white mud setting regulator. In some optional embodiments, the amount of sugarcane fiber added is 0.1% to 3% of the mass of the slurry.

[0042] In a preferred embodiment, the aging time is 5 to 10 days; in some more preferred embodiments, the aging time is 7 days.

[0043] In this invention, the particle size distribution of the materials in the slurry system is uneven, with large particles of electrolytic manganese slag and small particles of bagasse mud. As aging progresses, the small particles in the bagasse mud continuously dissolve and diffuse around the large particles of electrolytic manganese slag, eventually adhering to the surface of the large particles. Under the activation effect of an alkaline environment, the electrolytic manganese slag is modified, ultimately yielding a manganese mud setting regulator. It is worth noting that the term "manganese mud setting regulator" is the product name used in this invention; essentially, the resulting product is still a cement / concrete setting regulator.

[0044] In a preferred embodiment, stirring is also performed during the aging process; the shear force of the stirring makes the slurry more uniform and delicate, while preventing material segregation, separation, stratification, etc.

[0045] In a preferred embodiment, the aging process is carried out under sealed conditions, and the aging environment is a slightly negative pressure environment; the ambient temperature of the aging environment is ≤30℃, preferably 20℃~30℃; and the relative humidity of the aging environment is 45%~55%.

[0046] A second aspect of the present invention is to provide a setting regulator for cement.

[0047] The cement setting regulator includes the manganese white mud setting regulator prepared by the resource utilization treatment method of bagasse white mud and electrolytic manganese slag as described in the first aspect. It is understood that, in addition to the manganese white mud setting regulator, the cement setting regulator may also include other functional components, and the present invention does not impose any restrictions on the specific composition of the cement setting regulator.

[0048] A third aspect of the invention is to provide the use of the cement setting regulator as described in the second aspect in the field of concrete.

[0049] It is understood that the uses include, but are not limited to, cement products or building products made with the cement setting regulator, cement preparation methods or construction methods based on the cement setting regulator, etc.; provided that the cement setting regulator is included, any product or method can be used as an embodiment of the third aspect of the present invention.

[0050] In the embodiments of this invention, the electrolytic manganese slag is all from the waste residue discharged during the production process of an electrolytic manganese enterprise in Southwest China, and the bagasse white mud is all from the waste residue discharged during the production process of a papermaking enterprise in Southwest China.

[0051] Example 1

[0052] S1: The high-moisture-content electrolytic manganese slag raw material is sun-dried and then crushed by a jaw crusher to obtain electrolytic manganese slag with a particle size ≤10mm.

[0053] S2: The bagasse white mud with high moisture content is filtered to separate solid material with a moisture content of ≤5% and bagasse white mud wastewater for later use.

[0054] S3: Mix 70 parts electrolytic manganese slag, 20 parts bagasse white mud, and 10 parts tap water according to the mass ratio, and input the mixture into a sealed aging tank. Maintain the air pressure in the aging tank at less than 1 atmosphere, the temperature at 25 degrees Celsius, and the relative humidity at 50%. Install a mixer in the aging tank and continuously stir at a stirring speed of 50 rpm. Aging continues for 7 days (7*24h), and then the manganese white mud coagulant is obtained from the aging tank.

[0055] Example 2

[0056] It is basically the same as Example 1, except that it is mixed according to the mass ratio of 85 parts of electrolytic manganese slag, 5 parts of bagasse white mud and 10 parts of tap water.

[0057] Example 3

[0058] It is basically the same as Example 1, except that it is mixed according to the mass ratio of 80 parts of electrolytic manganese slag, 10 parts of bagasse white mud and 10 parts of tap water.

[0059] Example 4

[0060] It is basically the same as Example 1, except that:

[0061] In step S3, an additional 1 part of bagasse white mud wastewater (separated in S2) and 2 parts of sugarcane fiber are added to the aging tank.

[0062] Example 5

[0063] It is basically the same as Example 1, except that:

[0064] In step S3, an additional 0.1 parts of float glass desulfurization ash and 1 part of sugarcane fiber are added to the aging tank.

[0065] Experimental Example 1

[0066] The optimal dosage of manganese white mud setting regulator in cement was determined by small-scale grinding tests using raw materials from a cement plant, based on the manganese white mud setting regulator prepared in Example 1. Different addition ratios of manganese white mud setting regulator were used in Examples 1-6 shown in Table 1 below. All values ​​in Table 1 are in parts by mass (dimensionless).

[0067] Table 1

[0068]

[0069]

[0070] Table 2 below shows the physical test results for Examples 1 to 6 in the small grinding test.

[0071] Table 2

[0072]

[0073] As shown in Table 2, the manganese white mud setting modifier of this invention has a weaker ability to regulate cement setting time than ordinary desulfurized gypsum. With increasing dosage of the manganese white mud setting modifier, the cement setting time tends to shorten. The manganese white mud setting modifier has a significant impact on the fluidity of cement paste; with increasing dosage, the cement fluidity deteriorates, and the loss of fluidity in the paste increases. The manganese white mud setting modifier promotes the compressive strength of cement; with increasing dosage, the compressive strength tends to increase. This is because the excess alkali in the manganese white mud setting modifier has a certain activating effect on the cement paste, promoting the improvement of cement strength. The manganese white mud setting modifier prepared from bagasse white mud alkali-modified electrolytic manganese slag can be used in cement production.

[0074] Experimental Example 2

[0075] Based on the performance in Example 1, cement was prepared using the proportions in Example 4 of Example 1, and the manganese white mud setting modifier was replaced sequentially with the manganese white mud setting modifiers in Examples 2 to 5; small-scale grinding tests were conducted under the same conditions as in Example 1, and the physical test results are shown in Table 3.

[0076] Table 3

[0077]

[0078] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for the resource-based treatment of bagasse white mud and electrolytic manganese slag, characterized in that, Includes the following steps: A slurry containing bagasse white mud and crushed electrolytic manganese slag is aged to obtain a manganese white mud coagulant; the mass ratio of the bagasse white mud, the electrolytic manganese slag and water is (1~3):(6~8):1; The aging period is 5 to 10 days, the aging is carried out under sealed conditions, the ambient temperature during aging is ≤30℃, and the relative humidity during aging is 45% to 55%. The process before the resource recovery method includes: reducing the moisture content of bagasse mud to 5%~20%; The slurry comprises bagasse mud, electrolytic manganese slag, and water.

2. The resource recovery method according to claim 1, characterized in that, The bagasse white mud is treated by at least one of sun drying or solid-liquid separation.

3. The resource recovery method according to claim 1, characterized in that, The particle size of the electrolytic manganese slag after the crushing process is ≤10mm.

4. The resource recovery method according to claim 1, characterized in that, The resource recovery process includes the following steps before the above method: Reduce the moisture content of electrolytic manganese slag to 5%~10%; And / or, neutralize the pH of the electrolytic manganese slag to 7-8.

5. The resource recovery method according to claim 1, characterized in that, The slurry includes a modifier; the modifier includes at least one of bagasse white mud wastewater, float glass desulfurization ash, or sugarcane fiber.

6. The resource recovery method according to claim 5, characterized in that, The amount of the modifier added is 0.01% to 5% of the mass of the slurry.

7. A cement setting regulator, characterized in that, The manganese white mud coagulant prepared by the resource utilization treatment method of bagasse white mud and electrolytic manganese slag as described in any one of claims 1 to 6.

8. The use of the cement setting regulator as described in claim 7 in the field of concrete.

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