A method for high value-added comprehensive utilization of calcium silicate or calcium silicate phase materials

Abstract

The application discloses a method for comprehensively utilizing calcium silicate or calcium silicate phase-containing materials with high added value, and belongs to the fields of resource comprehensive utilization, solid waste resource and mineral material processing. The method selects various solid materials, by-products and waste materials containing calcium silicate or calcium silicate phase generated in the fields of ore mining and processing, metallurgy, materials, chemical industry, environment and the like, including but not limited to one or more of the mixtures of common high-calcium fly ash, yellow phosphorus slag, red mud, blast furnace slag and various materials containing calcium silicate or calcium silicate after artificial modification as raw materials, carries out selective nitric acid leaching, leaching liquid hydrolysis, uses the hydrolysis liquid to produce high-purity gypsum and regenerated nitric acid, returns the regenerated nitric acid to the leaching procedure, and sequentially carries out washing, drying, acid leaching and calcination on the obtained solid phase after hydrolysis to prepare white carbon black, porous silicon dioxide or high-purity silicon dioxide. The method has mild process conditions, the product has high added value, and can completely solve the bottleneck problems in sustainable development in multiple fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of resource comprehensive utilization, solid waste resource and mineral material processing, and particularly relates to a method for high value-added comprehensive utilization of calcium silicate or calcium silicate phase-containing material. BACKGROUND

[0002] The top five elements in the earth's crust are oxygen, silicon, aluminum, iron and calcium, with contents of O (45.2%), Si (27.2%), Al (8%), Fe (5.8%) and Ca (5.06%), respectively. Although the content of calcium silicate minerals in the earth's crust is not abundant, it is very easy to produce calcium silicate or calcium silicate in human production activities. For example, the calcium silicate in cement is the main component of cement, accounting for about 70% of the volume of cement. There are three common ways to generate calcium silicate or calcium silicate in human activities: 1. Hydrothermal reaction, by mixing silicic acid, lime and water in a certain proportion and then performing hydrothermal reaction to generate calcium silicate. 2. High-temperature calcination, calcium oxide and silicon dioxide are easily fused to generate calcium silicate or various calcium silicates at high temperatures. 3. Limestone and silicon dioxide reaction, first, limestone is calcined to obtain lime, and then the lime is reacted with silicon dioxide to generate calcium silicate. Therefore, a large amount of calcium silicate and / or calcium silicate materials or solid waste will be generated in the fields of ore mining, mineral processing, metallurgy, materials, chemical industry, etc., including but not limited to common high-calcium fly ash, yellow phosphorus slag, red mud, smelting slag, etc. and various materials containing calcium silicate and / or calcium silicate after artificial modification. In addition to containing a large amount of calcium and silicon resources, the above-mentioned materials also contain a considerable amount of non-ferrous metals, rare earths, rare metals, etc., but most of them can only be used as industrial solid waste or hazardous waste at present, which not only causes serious environmental pressure, but also leads to a large amount of resource waste.

[0003] In addition, a large amount of solid waste in China, such as coal gangue, gasification slag, fly ash, beneficiation tailings, smelting slag and other solid waste contains a large amount of aluminum, silicon and valuable lithium, gallium, rare earth and other resources, and the resource utilization of these solid wastes can reduce the exploitation of mineral resources. A large number of studies recover and utilize valuable metal components in the above-mentioned large solid waste, but the large amount of associated silicon elements are difficult to effectively utilize, which inevitably brings certain secondary pollution, so the resource utilization of a large amount of silicon in the above-mentioned solid waste is the main factor limiting the complete harmless and reduction of large industrial solid waste. Under the current technical conditions, the utilization mode of silicon resources in the above-mentioned solid waste mainly includes the preparation of silica-based materials such as aerogel, hydrated calcium silicate and white carbon black, and the preparation process of products such as aerogel and white carbon black has problems such as large difference in product performance, complex process flow, and difficulty in recycling of alkali medium, which is difficult to realize large-scale utilization. However, it is very easy and low-cost to prepare calcium silicate using the associated silicon elements in the above-mentioned materials, and a large number of studies have confirmed that it is easy and low-cost to synthesize calcium silicate using a large amount of associated silicon resources in various large industrial solid wastes.

[0004] Therefore, the research and development of a high-efficiency resource utilization, harmless and high-value method for various materials or solid wastes containing calcium silicate or calcium silicate, and a green and environmentally friendly production process can produce important economic value, environmental value and important practical significance. SUMMARY

[0005] In view of the above technical problems, the present application provides a method for high-value comprehensive utilization of materials containing calcium silicate or calcium silicate phase.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a method for high-value comprehensive utilization of materials containing calcium silicate or calcium silicate phase, comprising the following steps:

[0007] (1) taking the material containing calcium silicate and / or calcium silicate phase generated in various industrial fields as raw material;

[0008] (2) grinding the raw material selected in step (1) for large block size, then carrying out nitric acid leaching at room temperature, and after leaching, solid-liquid separation is carried out to obtain leaching liquid and leaching residue;

[0009] (3) heating the leaching liquid obtained in step (2) to carry out chemical reaction, and after reaction, solid-liquid separation is carried out to obtain solid phase and liquid phase;

[0010] (4) adding sulfuric acid to the liquid phase obtained in step (3) to carry out precipitation reaction, and after precipitation, solid-liquid separation is carried out to obtain liquid phase and high-purity gypsum product;

[0011] (5) distilling the liquid phase obtained in step (4) with a sulfuric acid solution, distilling to obtain vapor and solid phase crystallization, condensing the vapor to obtain regenerated nitric acid, and returning the regenerated nitric acid to step (2) for leaching reaction;

[0012] (6) sequentially washing and drying the solid phase obtained in step (3) to obtain dried solid phase, and returning the washing liquid obtained by solid-liquid separation during the washing to the nitric acid leaching process of step (2);

[0013] (7) acid leaching the dried solid phase obtained in step (6), and obtaining leaching liquid and solid phase by solid-liquid separation after the acid leaching is completed;

[0014] (8) calcining the solid phase obtained in step (7) to obtain silicon-based material. The silicon-based material is white carbon black, porous silicon dioxide or high-purity silicon dioxide.

[0015] As a preferred embodiment of the present application, the calcium silicate and / or calcium silicate containing material is various solid materials, intermediate products, by-products and waste materials containing calcium silicate or calcium silicate phase generated in the fields of ore mining and processing, metallurgy, materials, chemical industry, energy, environment, etc. The chemical composition of the calcium silicate and / or calcium silicate containing material contains CaO and SiO2, including but not limited to common high-calcium fly ash, yellow phosphorus slag, red mud, blast furnace slag, artificially modified synthetic calcium silicate or calcium silicate containing materials and the like. More preferably, the calcium silicate and / or calcium silicate containing material is at least one of high-calcium fly ash, yellow phosphorus slag, red mud, blast furnace slag, artificially modified synthetic calcium silicate or calcium silicate containing materials and by-products.

[0016] As a preferred embodiment of the present application, in step (2), the conditions of nitric acid leaching are as follows: the leaching temperature is 10-40℃, the volume concentration of nitric acid is 10%-50%, the liquid-solid mass ratio is 10:1-3:1, and the leaching time is 0.5-3h.

[0017] As a preferred embodiment of the present application, in step (3), the heating temperature is 60-100℃, and the time is 0.5-3h.

[0018] As a preferred embodiment of the present application, in step (4), the mass concentration of the sulfuric acid solution is 50%-98%, the volume ratio of the liquid to the sulfuric acid solution is 1:5-1:50, the temperature of the precipitation reaction is 10-100℃, and the time is 0.5-3h.

[0019] As a preferred embodiment of the present application, in step (5), the mass concentration of the sulfuric acid solution is 50%-98%, the volume ratio of the sulfuric acid solution to the liquid phase is 1:2-1:10, and the distillation temperature is 80-100℃.

[0020] As the preferred embodiment of the present application, the solvent used for washing is water or nitric acid solution, when water is used for washing, the washing temperature is 10-100℃, the solid-liquid mass ratio of the washing liquid is 8:1-3:1, the washing time is 0.5-3h, and the washing times are 1-3 times of countercurrent washing; when water is used for washing, the volume concentration of the nitric acid solution is 3%-10%, and the rest conditions are the same as those of water washing; the drying temperature is 100-300℃, and the drying time is 0.5-10h.

[0021] As the preferred embodiment of the present application, the acid leaching conditions in the step (7) are as follows: the leaching agent is at least one of sulfuric acid, nitric acid and hydrochloric acid, the acid volume concentration is 5%-80%, the leaching reaction temperature is 50-200℃, the solid-liquid mass ratio of the leaching liquid is 8:1-2:1, the leaching time is 0.5-3h, and the leaching reaction section number is 1-5 times of countercurrent leaching.

[0022] As the preferred embodiment of the present application, in the step (8), the calcination conditions of the solid phase are as follows: the calcination temperature is 700-2500℃, and the calcination time is 0.5-3h.

[0023] As the preferred embodiment of the present application, the purity of the high-purity gypsum is above 80%, and the highest can be more than 95%; the purity of the high-purity silicon dioxide is higher than 99%, and the highest can be higher than 99.99%-99.9999%.

[0024] The principle of the present application is as follows:

[0025] Firstly, the raw material is selectively leached by nitric acid under mild conditions to leach silicon in calcium silicate or calcium silicate, and the valuable elements in the leaching residue can be further separated and recovered. Secondly, the silicon in the leaching liquid is crystallized and precipitated in the form of solid phase by heating hydrolysis, and the separation and purification of silicon and the recovery of silicon are realized by further solid-liquid separation, and the heating hydrolysis of silicon in the solution does not need additional reagents but only needs heating. Thirdly, the impurities in the silicon dioxide are removed by further acid leaching. Finally, the silicon dioxide in the material is separated from other components in the process of leaching, precipitation and leaching and impurity removal, and is polymerized into silicon dioxide again, and the crystal structure and microstructure are changed in the process, and according to the differences of the raw materials and the process conditions, the purity and pore structure of the final obtained silicon dioxide are different, so according to the differences of the raw materials and the process conditions, the final obtained silicon dioxide can be white carbon black, porous silicon dioxide or high-purity silicon dioxide. The hydrolysis liquid realizes the recycling of nitric acid in the process by regenerating the nitric acid therein, which is beneficial to further reducing the cost of reagents.

[0026] Compared with the prior art, the method has the beneficial effects that: the method can comprehensively utilize the material containing calcium silicate or calcium silicate phase, including a large amount of material or solid waste containing calcium silicate and / or calcium silicate phase generated in the fields of ore mining, mineral processing, metallurgy, materials, chemical industry and the like, including but not limited to common high-calcium fly ash, yellow phosphorus slag, red mud, smelting slag and the like and various materials containing calcium silicate and / or calcium silicate after artificial modification, and the method realizes the conversion of a large amount of silicon, calcium and the like in the material into high-value products or intermediate products through a mild reaction condition system, compared with the traditional field, the method realizes fine resource utilization of multiple components, can generate higher added value, and completely solves the sustainable development and environmental protection problems faced in multiple fields. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A flow chart of the method for high-value comprehensive utilization of the material containing calcium silicate or calcium silicate phase.

[0028] Figure 2 A BET graph of the mesoporous silicon dioxide prepared in Example 3. DETAILED DESCRIPTION

[0029] The present application is not limited to the following examples, and various modifications and improvements can be made without departing from the spirit and scope of the present application. In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0030] A method for high-value comprehensive utilization of a material containing calcium silicate or calcium silicate phase, comprising the following steps:

[0031] (1) taking the material containing calcium silicate and / or calcium silicate generated in various industrial fields as raw material, common high-calcium fly ash, yellow phosphorus slag, red mud, blast furnace slag and various materials containing calcium silicate or calcium silicate after artificial modification and by-products, and selecting a mixture of one or more materials.

[0032] (2) crushing and grinding the selected raw material in step (1) for large block size, and then carrying out nitric acid leaching under room temperature conditions, and after the leaching is completed, solid-liquid separation is carried out to obtain a leaching solution and a leaching residue.

[0033] (3) heating the leaching solution obtained in step (2) to carry out chemical reaction, and after the reaction is completed, solid-liquid separation is carried out to obtain a solid phase and a liquid phase.

[0034] (4) adding a sulfuric acid solution to the liquid phase obtained in step (3) to carry out a precipitation reaction, and after the precipitation is completed, solid-liquid separation is carried out to obtain a liquid phase and a high-purity gypsum product.

[0035] (5) Distill the liquid phase obtained in step (4) with sulfuric acid solution, distill to obtain steam and solid phase crystallization, condense the steam to obtain regenerated nitric acid, and return the regenerated nitric acid to step (2) for leaching reaction.

[0036] (6) The solid phase obtained in step (3) is sequentially washed and dried to obtain a dried solid phase, and the washing liquid obtained by solid-liquid separation in the washing process is returned to the nitric acid leaching process of step (2).

[0037] (7) The solid phase obtained after drying in step (6) is subjected to acid leaching, and after acid leaching, solid-liquid separation is performed to obtain leaching liquid and solid phase.

[0038] (8) The solid phase obtained in step (7) is calcined to obtain a silicon-based material: white carbon black, porous silica or high-purity silica. In the process of leaching, precipitation, and leaching impurity removal, silicon oxide in the material is separated from other components and re-polymerized into silicon dioxide, and the crystal structure and microstructure change. According to the differences in raw materials and process condition parameters, the purity and pore structure of the final obtained silicon dioxide are different. Therefore, according to the differences in raw materials and process condition parameters, the final obtained silicon dioxide can be white carbon black, porous silica or high-purity silica.

[0039] (9) The leaching residue obtained in step (2) can be further separated and recovered for valuable components.

[0040] (10) The solid phase crystallization obtained in step (5) can be further separated and recovered for valuable metals.

[0041] (11) The leaching liquid obtained in step (7) can be further separated and recovered for valuable metals and regenerated leaching agent.

[0042] In step (2) of the present application, the reaction conditions for nitric acid leaching at room temperature are as follows: the leaching reaction temperature is preferably 10-40℃, further preferably 20-40℃, and more preferably 25-35℃. The volume concentration of nitric acid is preferably 10%-50%, further preferably 20%-40%, and more preferably 20%-30%. The solid-liquid ratio of the leaching liquid is preferably 10:1-3:1, further preferably 8:1-4:1, and more preferably 8:1-5:1. The leaching time is preferably 0.5-3h, further preferably 1-3h, and more preferably 1.5-2.5h.

[0043] In step (3) of the present application, the heating conditions are as follows: the reaction temperature is preferably 60-100℃, further preferably 80-100℃, and more preferably 90-100℃; and the reaction time is preferably 0.5-3h, further preferably 1-3h, and more preferably 1.5-3h.

[0044] In step (4) of the present application, the conditions for adding sulfuric acid for precipitation reaction are as follows: the mass concentration of the added sulfuric acid solution is preferably 50% to 98%, further preferably 70% to 98%, and more preferably 98%; the volume ratio of the sulfuric acid solution to the liquid phase to be precipitated is preferably 1:5 to 1:50, further preferably 1:8 to 1:40, and more preferably 1:8 to 1:20; the reaction temperature is preferably 10 to 100℃, further preferably 10 to 70℃, and more preferably 15 to 40℃; and the reaction time is preferably 0.5 to 3h, further preferably 0.5 to 2h, and more preferably 0.5 to 1.5h.

[0045] In step (5) of the present application, the conditions for adding sulfuric acid solution for reaction and nitric acid distillation regeneration are as follows: the mass concentration of the added sulfuric acid solution is preferably 50% to 98%, further preferably 70% to 98%, and more preferably 98%; the volume ratio of the sulfuric acid solution to the liquid phase is preferably 1:2 to 1:10, further preferably 1:2 to 1:8, and more preferably 1:3 to 1:6; and the reaction temperature is preferably 80 to 100℃, further preferably 85 to 100℃, and more preferably 85 to 95℃.

[0046] In step (6) of the present application, the washing conditions are as follows: the solvent used for washing is preferably water or a nitric acid solution, and further preferably water is used for washing; when water is used as the solvent, the reaction temperature is preferably room temperature to 100℃, further preferably 20 to 40℃, and more preferably 25 to 40℃. The solid-liquid mass ratio is preferably 8:1 to 3:1, further preferably 6:1 to 3:1, and more preferably 5:1 to 3:1. The washing time is preferably 0.5 to 3h, further preferably 1 to 3h, and more preferably 1 to 2h. The washing times are preferably 1 to 3 times of countercurrent washing, further preferably 2 to 3 times of countercurrent washing, and more preferably 2 times of countercurrent washing. When a nitric acid solution is used as the solvent, the volume concentration of the nitric acid is preferably 3% to 10%, further preferably 3% to 8%, and more preferably 3% to 6%. The remaining conditions are the same as those for water washing.

[0047] In step (6) of the present application, the drying conditions are as follows: the drying temperature is preferably 100 to 300℃, further preferably 120 to 200℃, and more preferably 130 to 180℃; and the drying time is preferably 0.5 to 10h, further preferably 1 to 10h, and more preferably 2 to 10h.

[0048] In step (7) of the present application, the acid leaching reaction conditions are as follows: the leaching agent is preferably at least one of sulfuric acid, nitric acid and hydrochloric acid, more preferably sulfuric acid; the acid volume concentration is preferably 5% to 80%, further preferably 10% to 80%, more preferably 30% to 80%; the leaching reaction temperature is preferably 50 to 200°C, further preferably 80 to 200°C, more preferably 90 to 200°C; the leaching liquid-solid ratio is preferably 8:1 to 2:1, further preferably 6:1 to 3:1, more preferably 5:1 to 3:1; the leaching time is preferably 0.5 to 3h, further preferably 1 to 3h, more preferably 1.5 to 3h; and the leaching reaction stage number is preferably 1 to 5 stages of countercurrent leaching, more preferably 2 to 3 stages of countercurrent leaching.

[0049] In step (8) of the present application, the calcination conditions of the solid phase obtained by acid leaching are as follows: the calcination temperature is preferably 700 to 2500°C, further preferably 700 to 2300°C, more preferably 700 to 2000°C; and the calcination time is preferably 0.5 to 3h, more preferably 1 to 3h.

[0050] The purity of the high-purity gypsum prepared by the method is above 80%, and can be more than 95%; the purity of the silicon-based material high-purity silicon dioxide prepared by the method is higher than 99%, and can be higher than 99.99% to 99.9999%.

[0051] Example 1

[0052] A method for high-value comprehensive utilization of calcium silicate or calcium silicate phase-containing material, which comprises the following specific steps:

[0053] (1) The raw material selected is a certain high-calcium fly ash, and the chemical composition thereof is as follows: CaO content 46.3%, Al2O3 content 12.9%, SiO2 content 28.7%, and other component content 12.1%. The high-calcium fly ash is ground to a particle size of less than 0.074 mm, and the ground high-calcium fly ash is subjected to nitric acid leaching under room temperature conditions, and the leaching reaction conditions are as follows: leaching reaction temperature 30°C, nitric acid volume concentration 30%, leaching liquid-solid volume ratio 6:1, and leaching time 2h. After the leaching reaction is completed, solid-liquid separation is performed by filtration to obtain a leaching liquid and a leaching residue. The leaching residue can be used as an intermediate product for further recovery of metal and non-metal valuable components therein.

[0054] (2) The leaching liquid is heated to 90°C for hydrolysis reaction, and the hydrolysis reaction time is 2h. After the reaction is completed, filtration is performed to obtain a hydrolysis solid phase and a hydrolysis liquid phase.

[0055] (3) The hydrolyzed solid phase is washed with water, the washing temperature is 25°C, the washing liquid to solid mass ratio is 4:1, the washing time is 2h, and after washing, solid-liquid separation is performed to obtain a washing liquid and a washed solid phase, and the washing liquid is returned to the nitric acid normal temperature leaching process. The washed solid phase is dried by heating, the drying temperature is 150°C, and the drying time is 3h.

[0056] (4) The dried solid phase is subjected to acid leaching purification, the leaching agent for acid leaching purification is sulfuric acid, the acid volume concentration is 40%, the leaching reaction temperature is 90°C, the leaching liquid to solid ratio is 4:1, the leaching time is 2h, the leaching reaction section number is 2 sections of countercurrent leaching, and after acid leaching, solid-liquid separation is performed to obtain an acid leaching liquid and an acid leaching residue. The acid leached acid leaching residue is calcined at 800°C for 1h to obtain white carbon black. The obtained white carbon black includes the following mass percentage chemical components: TiO2, SiO2, Al2O3, CaO, MgO and Fe2O3, which are 0.19%, 82.07%, 0.11%, 0.62%, 0.031% and 0.024% respectively, and the balance is other components. The purity of the white carbon black is 99.2%. The acid leaching liquid can be further recovered for metal elements.

[0057] (5) The hydrolyzed liquid phase is subjected to a precipitation reaction by adding sulfuric acid, the mass concentration of the added sulfuric acid is 98%, the sulfuric acid addition amount is a sulfuric acid volume to the volume of the liquid phase to be precipitated ratio of 1:10, the precipitation reaction temperature is 30°C, and the reaction time is 1h. After the reaction is completed, high-purity gypsum and a precipitated liquid phase are obtained by filtration. The high-purity gypsum includes the following mass percentage chemical components: CaO content 31.80%, MgO content 0.081%, Al2O3 content 0.058%, TiO2 content 0.0028%, and SiO2 content less than 0.02%. The purity of the high-purity gypsum is 95%, which meets the product index requirements of high-purity gypsum.

[0058] (6) The precipitated liquid phase is further added with sulfuric acid and subjected to distillation. The mass concentration of the added sulfuric acid is 98%, the sulfuric acid addition amount is a sulfuric acid volume to the volume of the liquid phase to be precipitated ratio of 1:4, and the distillation temperature is 80°C. After distillation, steam and a crystallized solid phase are obtained. The steam is condensed to obtain dilute nitric acid, which is returned to the leaching process. The regenerated nitric acid and the new nitric acid have the same leaching effect under the same conditions. The crystallized solid phase obtained by distillation can be further recovered for valuable components.

[0059] Example 2

[0060] A method for comprehensively utilizing calcium silicate or calcium silicate phase-containing material with high added value, which specifically comprises the following steps:

[0061] (1) In this embodiment, the selected raw material is a certain yellow phosphorus slag, and the chemical composition thereof is as follows: CaO content 46.78%, SiO2 content 41.01%, MgO content 1.03%, Al2O3 content 3.65%, Fe2O3 content 0.056%, P2O5 content 3.07%, and other component content 4.404%. The yellow phosphorus slag is ground to a particle size of 100% of 0.074 mm, and the ground yellow phosphorus slag is subjected to nitric acid leaching at room temperature. The leaching reaction conditions are as follows: leaching reaction temperature 25°C, nitric acid volume concentration 25%, leaching liquid to solid volume ratio 7:1, and leaching time 2 h. After the leaching reaction is completed, solid-liquid separation is performed by filtration to obtain a leaching liquid and a leaching residue. The leaching residue can be used as an intermediate product for further recovery of metal and non-metal valuable components.

[0062] (2) The leaching liquid is heated to 95°C for hydrolysis reaction, and the hydrolysis reaction time is 2 h. After the reaction is completed, filtration is performed to obtain a hydrolysis solid phase and a hydrolysis liquid phase.

[0063] (3) The hydrolysis solid phase is washed with water at a washing temperature of 25°C, a washing liquid to solid mass ratio of 4:1, and a washing time of 2 h. After washing, solid-liquid separation is performed to obtain a washing liquid and a washed solid phase. The washing liquid is returned to the nitric acid normal temperature leaching process. The washed solid phase is dried by heating, and the drying temperature is 150°C and the drying time is 5 h.

[0064] (4) After drying, the hydrolysis solid phase is subjected to acid leaching purification. The leaching agent for acid leaching purification is sulfuric acid, the acid volume concentration is 70%, the leaching reaction temperature is 150°C, the leaching liquid to solid ratio is 4:1, and the leaching time is 2 h. The acid leaching is performed by 3-stage countercurrent leaching. After acid leaching, solid-liquid separation is performed to obtain a leaching liquid and a solid phase. The purity of silicon dioxide in the obtained acid leaching solid phase is as high as 99.99%. The acid leaching solid phase is calcined at 2000°C for 2 h to obtain high-purity quartz. The leaching liquid can be further used to recover metal elements.

[0065] (5) The hydrolysis liquid phase is subjected to precipitation reaction by adding sulfuric acid. The mass concentration of the added sulfuric acid is 98%, the sulfuric acid addition amount is 1:10 of the volume ratio of sulfuric acid to the hydrolysis liquid phase to be precipitated, the precipitation reaction temperature is 25°C, and the reaction time is 1 h. After the reaction is completed, high-purity gypsum and a precipitation liquid phase are obtained by filtration. The high-purity gypsum includes the following mass percentage chemical components: CaO content 32.01%, MgO content 0.072%, Al2O3 content 0.051%, and SiO2 content less than 0.018%. The high-purity gypsum meets the product index requirements, and the purity of the high-purity gypsum is more than 93.5%.

[0066] (6) The precipitated liquid phase is further added with sulfuric acid and distilled, the mass concentration of the added sulfuric acid is 98%, the volume ratio of the added sulfuric acid to the liquid phase to be precipitated is 1:4, the distillation temperature is 90°C, and after distillation, steam and crystalline solid phase are obtained, the steam is condensed to obtain dilute nitric acid, the dilute nitric acid is returned to the leaching process, regenerated nitric acid and new nitric acid have the same leaching effect under the same conditions, and the crystalline solid phase obtained by distillation can be further recovered for valuable components.

[0067] Example 3

[0068] A method for comprehensively utilizing high-value calcium silicate or calcium silicate phase materials, the specific steps are as follows:

[0069] (1) In this embodiment, the selected raw material is a certain hot liquid blast furnace slag, and the chemical composition is: CaO content 33.12%, SiO2 content 31.99%, MgO content 9.08%, Al2O3 content 13.82%, K2O content 0.39%, Na2O content 0.71%, CaF2 content 1.23%, TiO2 content 1.39%, rare earth content 0.81%, TFe content 1.11%, and other components content 6.35%. After water quenching of the hot liquid blast furnace slag, the slag is ground to a particle size of -0.045 mm, and then the ground blast furnace slag is subjected to nitric acid leaching at room temperature, and the leaching reaction conditions are: leaching reaction temperature 30°C, nitric acid volume concentration 30%, liquid to solid volume ratio 7:1, and leaching time 2h. After the leaching reaction is completed, solid-liquid separation is performed by filtration to obtain a leaching liquid and a leaching residue. The leaching residue is used as an intermediate product to further recover valuable metal and non-metal components therein.

[0070] (2) The leaching liquid is heated to 95°C for hydrolysis reaction, the hydrolysis reaction time is 2h, and after the reaction is completed, filtration is performed to obtain a hydrolysis solid phase and a hydrolysis liquid phase.

[0071] (3) The hydrolysis solid phase is washed with water, the washing temperature is 25°C, the washing liquid to solid mass ratio is 4:1, and the washing time is 2h. After washing, solid-liquid separation is performed to obtain a washing liquid and a washed solid phase, and the washing liquid is returned to the nitric acid normal temperature leaching process; the washed solid phase is dried by heating, and the drying temperature is 150°C and the drying time is 3h.

[0072] (4) The dried hydrolysis solid phase is subjected to acid leaching purification, and the leaching agent for acid leaching is sulfuric acid, the acid volume concentration is 40%, the leaching reaction temperature is 100°C, the liquid to solid ratio is 4:1, the leaching time is 2h, and the acid leaching is performed by 2-stage countercurrent leaching. After acid leaching, solid-liquid separation is performed to obtain an acid leaching liquid and mesoporous silicon dioxide. The leaching liquid can be further recovered for metal elements.

[0073] The chemical multi-element analysis result of the obtained mesoporous silica is SiO2 content 99.5%, Al2O3 content 0.08%, CaO content 0.05%, MgO content 0.06%, Fe2O3 content 0.03%, and the balance is inevitable impurities. For example Figure 2 , the BET analysis result of the obtained mesoporous silica shows that the BET specific surface area of the obtained mesoporous silica is 552.1689 m 2 / g, the pore volume is 0.756234 cm 3 / g, and the average pore size is The type of the obtained adsorption isotherm can be seen that the adsorption isotherm belongs to H2 type of type IV, between H 2a type and H 2b type, closer to H 2b type, which shows that the pore structure of the material is complex, which may include typical "ink bottle" pores, tubular pores with uneven pore size distribution, and interstitial pores of densely packed spherical particles. H 2a type hysteresis loop is common in silica gels and some ordered three-dimensional mesoporous materials. H 2b type relative to H 2a type, the size distribution of the neck width is much wider, which is common in mesoporous foam silica (MCFs) and some ordered mesoporous silica materials after hydrothermal treatment. Therefore, it can be determined that the material belongs to mesoporous material.

[0074] (5) The hydrolysis liquid phase is precipitated by adding sulfuric acid, the mass concentration of the added sulfuric acid is 98%, the sulfuric acid addition amount is 1:10 of the volume ratio of sulfuric acid to the liquid phase to be precipitated, the precipitation reaction temperature is 25°C, and the reaction time is 1h. After the reaction is completed, high-purity gypsum and precipitated liquid phase are obtained by filtration, the high-purity gypsum includes the following mass percentage chemical components: CaO content 31.09%, MgO content 0.078%, Al2O3 content 0.031%, SiO2 content less than 0.019%, which meets the product index requirements of high-purity gypsum, and the purity of the high-purity gypsum is 98%.

[0075] (6) The precipitated liquid phase is further added with sulfuric acid and distilled, the mass concentration of the added sulfuric acid is 98%, the sulfuric acid addition amount is 1:4 of the volume ratio of sulfuric acid to the liquid phase to be precipitated, and the distillation temperature is 90°C. After distillation, steam and crystalline solid phase are obtained, the steam is condensed to obtain dilute nitric acid, which is returned to the leaching process, and the regenerated nitric acid and the new nitric acid have the same leaching effect under the same conditions. The crystalline solid phase obtained by distillation can be further recovered for valuable components.

[0076] The above is the whole content of the present application. Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for high value-added comprehensive utilization of a calcium silicate or calcium silicate phase-containing material, characterized in that, The method comprises the following steps: (1) selecting at least one of a material containing calcium silicate and / or calcium silicate as a raw material; (2) crushing and grinding the raw material selected in step (1), and then performing nitric acid leaching at room temperature, and after the leaching is completed, solid-liquid separation is performed to obtain a leaching solution and a leaching residue; (3) heating the leaching solution obtained in step (2) to perform a chemical reaction, and after the reaction is completed, solid-liquid separation is performed to obtain a solid phase and a liquid phase; (4) performing a precipitation reaction on the liquid phase obtained in step (3) by adding a sulfuric acid solution, and after the precipitation is completed, solid-liquid separation is performed to obtain a liquid phase and high-purity gypsum; (5) adding a sulfuric acid solution to the liquid phase obtained in step (4) to perform distillation, and distillation is performed to obtain steam and a solid phase crystal, the steam is condensed to obtain regenerated nitric acid, and the regenerated nitric acid is returned to step (2) to perform leaching reaction; (6) sequentially performing washing and drying on the solid phase obtained in step (3) to obtain a dried solid phase, and the washing liquid obtained through solid-liquid separation in the washing process is returned to the nitric acid leaching process of step (2); (7) performing acid leaching on the dried solid phase obtained in step (6), and after the acid leaching is completed, solid-liquid separation is performed to obtain a leaching solution and a solid phase; (8) performing calcination on the solid phase obtained in step (7) to obtain a silicon-based material.

2. The method for high value-added comprehensive utilization of the calcium silicate or calcium silicate phase-containing material according to claim 1, characterized in that, In step (1), the material containing calcium silicate and / or calcium silicate is various solid materials, intermediate products, by-products or waste materials containing calcium silicate or calcium silicate phases generated in the fields of ore mining and processing, metallurgy, materials, chemical industry, energy and environment; the chemical composition of the material containing calcium silicate and / or calcium silicate includes CaO and SiO2.

3. The method for high value-added comprehensive utilization of the calcium silicate or calcium silicate phase-containing material according to claim 1, characterized in that, In step (2), the conditions for nitric acid leaching are as follows: the leaching temperature is 10-40°C, the volume concentration of nitric acid is 10%-50%, the liquid-solid mass ratio is 10:1-2:1, and the leaching time is 0.5-3h.

4. The method for high value-added comprehensive utilization of the calcium silicate or calcium silicate phase-containing material according to claim 1, characterized in that, In step (3), the heating temperature is 60-100°C, and the heating time is 0.5-3h.

5. The method for high value-added comprehensive utilization of the calcium silicate or calcium silicate phase-containing material according to claim 1, characterized in that, In step (4), the mass concentration of the sulfuric acid solution is 50%-98%, the volume ratio of the liquid phase to the sulfuric acid solution is 1:5-1:50, the precipitation reaction temperature is 10-100°C, and the precipitation reaction time is 0.5-3h.

6. The method of claim 1, wherein the calcium silicate or calcium silicate phase-containing material is a calcium silicate or calcium silicate phase-containing material having a high added value. In step (5), the mass concentration of the sulfuric acid solution is 50%-98%, the volume ratio of the sulfuric acid solution to the liquid phase is 1:2-1:10, and the distillation temperature is 80-100°C.

7. The method of claim 1, wherein the calcium silicate or calcium silicate phase-containing material is a calcium silicate or calcium silicate phase-containing material having a high added value. In step (6), the washing solvent is water or a nitric acid solution, the washing temperature is 10-100°C, the washing liquid-solid mass ratio is 8:1-3:1, the washing time is 0.5-3h, the washing number is 1-3 times of countercurrent washing, the volume concentration of the nitric acid solution is 3%-10%, the drying temperature is 100-300°C, and the drying time is 0.5-10h.

8. The method of claim 1, wherein the calcium silicate or calcium silicate phase-containing material is used in a high value-added manner. In step (7), the acid leaching conditions are as follows: the leaching agent is at least one of sulfuric acid, nitric acid and hydrochloric acid, the acid volume concentration is 5%-80%, the leaching reaction temperature is 50-200°C, the leaching liquid-solid mass ratio is 8:1-2:1, the leaching time is 0.5-3h, and the leaching reaction section number is 1-5 times of countercurrent leaching.

9. The method of claim 1, wherein the calcium silicate or calcium silicate phase-containing material is a calcium silicate or calcium silicate phase-containing material having a high added value. The temperature of the calcination is 700-2500 DEG C, and the time of the calcination is 0.5-3h.

10. The method of claim 1, wherein the calcium silicate or calcium silicate phase-containing material is used in a high value-added manner. The silicon-based material is white carbon black, porous silica or high-purity silica, the purity of the high-purity silica is higher than 99%, and the purity of the high-purity gypsum is higher than 80%.

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