CN-121974584-A - Method for preparing geopolymer from wet desulfurization electrolytic manganese slag

Abstract

The invention discloses a method for preparing a geopolymer by wet desulfurization electrolytic manganese slag, which comprises the following steps of firstly drying solid wastes such as electrolytic manganese slag, potassium salt wet desulfurization electrolytic manganese slag, fly ash, steel slag and the like, metakaolin, mechanically grinding and pre-treating quicklime and mixing according to a certain proportion to form a dry functional mixture, preparing an alkaline excitant solution by liquid sodium silicate and sodium hydroxide according to a certain proportion, uniformly stirring and mixing the alkaline excitant solution and the dry functional mixture, adding a proper amount of water to form a flowable slurry, and finally pouring, molding, curing and demolding to obtain a high-performance geopolymer product after pre-curing and standard curing. Compared with the prior art, the method realizes the complete recycling and high-value utilization of various large-scale industrial solid wastes, and has the advantages of simple process flow, low carbon and environmental protection. The prepared geopolymer has the advantages of excellent mechanical property, high solid-waste mixing ratio, low pollutant leaching amount, obvious curing effect on environment harmful components and the like, and can also effectively solve the problem of environmental pollution caused by the accumulation of a large amount of industrial solid wastes represented by electrolytic manganese slag. In addition, the method can be widely applied to the field of green building materials such as building blocks, roadbed materials and the like, and has important significance for realizing bulk digestion and high-value utilization of electrolytic manganese slag and promoting sustainable development of manganese industry.

Inventors

• SHU JIANCHENG
• YOU YANYAN
• ZHAO HONGYUAN
• CHEN SHAOQIN

Assignees

• 西南科技大学

Dates

Publication Date

20260505

Application Date

20260206

Claims (5)

1. 1. The method for preparing the geopolymer by wet desulfurization of electrolytic manganese slag is characterized by comprising the following steps of: S100, carrying out low-temperature drying and grinding treatment on solid wastes such as electrolytic manganese slag, potassium salt wet desulphurization electrolytic manganese slag, fly ash, steel slag and the like, metakaolin and quicklime, and mixing according to a preset proportion to form a dry functional mixture. S200, preparing an alkaline excitant solution, namely mixing liquid sodium silicate with sodium hydroxide according to a certain proportion to prepare the alkaline excitant solution for standby. S300, adding the dry functional mixture and water into a reaction tank according to a certain mass ratio, adding an alkaline excitant solution, and mechanically stirring to form uniform slurry with proper fluidity. S400, pouring the slurry into a mold for molding, curing and demolding in advance, and curing in a standard curing environment until the curing reaches a specified age to obtain a geopolymer product, and testing the mechanical property, leaching toxicity and erosion resistance of the geopolymer product.
2. 2. The method for preparing geopolymer by wet desulfurization electrolytic manganese slag according to claim 1, wherein in the step S100, the mixing amount of solid wastes such as electrolytic manganese slag, potassium salt wet desulfurization electrolytic manganese slag, fly ash, steel slag and the like and metakaolin and quicklime is respectively set to 0-100%.
3. 3. The method for preparing a geopolymer from the wet desulfurization electrolytic manganese slag according to claim 1, wherein in the step S200, the addition amount of sodium hydroxide and liquid sodium silicate is calculated according to the proportion of an alkaline activator of M=n (SiO2) /n (Na2O) =1.0-2.0.
4. 4. The method for preparing geopolymer by wet desulfurization electrolytic manganese slag according to claim 1, wherein in the step S300, the mass ratio of the dry functional mixture to water is set to be 0.25-0.68.
5. 5. The method for preparing the geopolymer by the wet desulfurization electrolytic manganese slag according to claim 1, wherein in the step S400, the stirred and mixed slurry is poured into a 40 mm multiplied by 40 multiplied by mm multiplied by 40 mm die, pre-curing, curing and demolding are carried out under the conditions of 0-80 ℃ and 6-12 hours, and the obtained product is placed in a standard curing box for curing for 3-28 d after demolding, and the mechanical property, leaching toxicity and erosion resistance of the product are tested.

Description

Method for preparing geopolymer from wet desulfurization electrolytic manganese slag Technical Field The invention belongs to the technical field of industrial solid waste recycling and novel cementing materials, and relates to a method for preparing a geopolymer by wet desulfurization of electrolytic manganese slag, a product obtained by the method and application thereof. Background The metal manganese is used as an important strategic basic raw material and has irreplaceable functions in the fields of ferrous metallurgy, battery materials, chemical industry, national defense and military industry and the like. China is the biggest electrolytic manganese producing country, consuming country and export country worldwide, the yield of Chinese manganese metal is more than 92% of the total yield worldwide, and the manganese metallurgy industry becomes the special dominant industry of China. However, the industry is accompanied by serious environmental challenges while creating great economic value, and the core problem is a large amount of solid waste, namely electrolytic manganese slag, generated in the electrolytic manganese production process. The electrolytic manganese slag is industrial solid waste with high water content generated after leaching manganese ore in the production process of electrolytic manganese metal, and 10-12 tons of electrolytic manganese slag is generated in the wet electrolytic manganese process per 1 ton of manganese metal produced in China, so that a large amount of discharged electrolytic manganese slag seriously pollutes the local ecological environment. The electrolytic manganese slag has complex components, is rich in high-concentration soluble sulfate (such as manganese sulfate and ammonium sulfate), ammonia nitrogen and various heavy metal ions, occupies a large amount of land resources after long-term storage, and has the advantages that pollutants in the electrolytic manganese slag are leached and migrated and diffused by rainwater, and the electrolytic manganese slag is a continuous threat to surrounding water, soil and groundwater ecosystems, so that the electrolytic manganese slag becomes a major bottleneck for restricting the green sustainable development of the industry. Therefore, development of a technique for utilizing electrolytic manganese slag in a large scale and a high value is urgent. The geopolymer is a three-dimensional network inorganic polymer material formed by dissolving, gelling, polymerizing and solidifying aluminosilicate raw materials under alkaline conditions, has the potential of rapid hardening, early strength, high temperature resistance, corrosion resistance and good solid sealing of heavy metal ions, and is regarded as an ideal carrier for green building materials and solid waste recycling. At present, many researchers at home and abroad develop researches on preparing geopolymer by electrolytic manganese slag. However, the electrolytic manganese slag, the barium slag and the fly ash are simply compounded, no mention is made of any pretreatment of the electrolytic manganese slag, and the later expansion and cracking risks caused by soluble sulfate in the electrolytic manganese slag and the inhibition effect on gel network formation cannot be fundamentally eliminated, so that the obtained material has fundamental defects of long-term volume stability and durability. As patent CN114772962B provides a method for efficiently and comprehensively disposing red mud-electrolytic manganese slag, which is to pretreat the electrolytic manganese slag by water washing, and mainly aims to extract sodium sulfate instead of permanently stabilizing sulfate, and not completely remove or convert sulfate in all forms, wherein residual sulfate still can be activated under the condition of later alkaline excitation, so that the polymer has the risk of long-term volume stability. Meanwhile, a large amount of wastewater to be treated is generated in the water washing process, so that the process complexity and the environmental burden are increased. In fact, electrolytic manganese slag is rich in aluminosilicate and is a potential feedstock for the preparation of geopolymers. However, the traditional electrolytic manganese slag contains a large amount of soluble sulfate, so that the product is cracked in the later stage and the strength is reduced, meanwhile, the heavy metal leaching risk is increased, and the engineering application requirements are difficult to meet. The prior art fails to fundamentally solve the problem of damage of sulfate. Therefore, there is an urgent need to develop a new method for preparing high-performance geopolymer by thoroughly eliminating sulfate interference and cooperating with various solid wastes. The invention aims to overcome the defects of the prior art, adopts the desulfurized electrolytic manganese slag after sulfate is efficiently removed by a potassium salt system, develops preparation and performance research of electrolytic