Method for preparing white carbon black from silicon-aluminum-rich solid waste alkaline leaching residues
By treating the alkaline leaching residue of silicon-aluminum solid waste through acid leaching, precipitated silica and polyaluminum chloride as a byproduct are produced. This method solves the problems of complex processes, high energy consumption, and environmental pollution in existing technologies, and achieves efficient resource reuse and low-cost production.
Patent Information
- Application Number
- CN202511961397.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-01-23
AI Technical Summary
In existing technologies, the methods for preparing precipitated silica from industrial waste have problems such as complex processes, high energy consumption, easy product agglomeration, limited application scenarios, and high processing costs. Furthermore, the direct disposal of alkaline leaching residue can lead to soil salinization and environmental pollution.
The acid leaching method is used to treat the alkaline leaching residue of silicon-aluminum solid waste. The acid leaching solution is generated by reacting hydrochloric acid with the alkaline leaching residue. After alkaline precipitation, drying and acid washing, precipitated silica is prepared and polyaluminum chloride is produced as a by-product. This method simplifies the process and improves resource utilization.
This method enables efficient extraction of silicon and aluminum resources, producing standard-compliant silica and byproduct polyaluminum chloride, thereby reducing energy consumption and processing costs, and is suitable for green and environmentally friendly resource reuse.
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Figure CN121373042A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of white carbon black preparation, and particularly relates to a method for preparing white carbon black from silicon-rich aluminum solid waste alkali leaching residue. BACKGROUND
[0002] Industrial waste such as fly ash, lithium slag and water slag is reacted with sodium hydroxide solution to prepare products such as white carbon black. The remaining alkali leaching residue has a high pH, and direct disposal will lead to land salinization and damage to the agricultural environment. In addition, the silicon-aluminum bond in the alkali leaching residue is destroyed, and it does not react with alkali but can be dissolved by acid to obtain an acid solution rich in silicon and aluminum.
[0003] In the prior art, the method of preparing white carbon black from industrial waste residue is alkali leaching to obtain a sodium silicate solution, and the sodium silicate solution is carbonized and impurity-removed to obtain white carbon black. The waste residue obtained after alkali leaching still contains elements such as silicon, aluminum and calcium, and it is difficult to reduce the pH to neutral by water washing alone. The alkaline waste residue is not suitable for stacking or landfill, so it is treated by acid leaching and other operations to extract the remaining value. Industrial waste residue recovery of aluminum generally adds hydrochloric acid, concentrates, and recrystallizes multiple times to prepare crystalline aluminum chloride; or dissolves by adding acid, and then prepares crude sodium metaaluminate by adding alkali; or is processed into high-purity refined aluminum hydroxide by impurity removal and other operations. The above methods have problems such as complex process and high treatment cost. In the method of preparing white carbon black by carbonization of industrial waste residue, the white carbon black is prone to agglomeration, resulting in a small specific surface area of the white carbon black and limiting the application scenarios; the solution after carbonization is concentrated to prepare sodium carbonate, which has high energy consumption and low income.
[0004] Therefore, it is of great significance to provide a method for preparing white carbon black from silicon-rich aluminum solid waste alkali leaching residue, which has a simple process, low energy consumption and meets the requirements of the product. SUMMARY
[0005] The present application aims to provide a method for preparing white carbon black from silicon-rich aluminum solid waste alkali leaching residue.
[0006] In order to achieve the above-mentioned application purpose, the present application provides the following technical solution: The present application provides a method for preparing white carbon black from silicon-rich aluminum solid waste alkali leaching residue, comprising the following steps: 1) mixing the silicon-rich aluminum solid waste alkali leaching residue and acid to perform acid leaching to obtain an acid leaching solution; 2) adding alkali to the acid leaching solution to perform a silicon precipitation reaction, and then performing solid-liquid separation to obtain a silicon precipitation solution and silicon gel; drying the silicon gel and refining to obtain silicon powder; 3) mixing the silicon powder and acid to perform acid leaching, and then performing solid-liquid separation to obtain an acid leaching solution and a solid powder; washing and drying the solid powder to obtain white carbon black.
[0007] Preferably, the acid in step 1) is hydrochloric acid with a concentration of 1~4 mol / L; the mass ratio of the alkaline leaching residue of silicon-aluminum solid waste to the acid is 1:3~15.
[0008] As a preferred option, the silicon-aluminum solid waste alkali leaching residue is obtained by leaching industrial waste residue with alkali, and the industrial waste residue includes one or more of fly ash, lithium slag and water slag.
[0009] Preferably, the alkali in step 2) is a sodium hydroxide solution with a mass fraction of 8-32%, and the endpoint of the silica precipitation reaction is a pH value of 3-3.5 in the reaction system.
[0010] Preferably, the drying temperature in step 2) is 80~160℃, and the D90 of the silicon powder is ≤45μm.
[0011] Preferably, the acid in step 3) is hydrochloric acid, the concentration of which is 1.5~3 mol / L, and the mass ratio of silicon powder to hydrochloric acid is 1:2~4.
[0012] Preferably, the acid leaching temperature in step 3) is 60~80℃, and the drying temperature is 150~170℃.
[0013] Preferably, the silica precipitation solution in step 2) and the acid leaching solution in step 3) are mixed, and the mixture is sequentially adjusted for pH, aged, and concentrated by evaporation to obtain polyaluminum chloride.
[0014] Preferably, the reagent for adjusting the pH value is sodium hydroxide solution, the pH value is adjusted to 4~5, the aging temperature is 20~80℃, and the aging time is 4~36h.
[0015] The beneficial effects of this invention are: This invention involves directly acid leaching the alkaline leaching residue of silicon-aluminum-rich solid waste, thereby dissolving the silicon and aluminum in the waste residue to obtain a silicon-aluminum-rich acid leaching solution. The leaching rate of silicon in the waste residue can reach over 50%, and the leaching rate of aluminum can reach over 90%. The pH of the acid leaching solution is adjusted by alkali, allowing silicic acid to precipitate as silica gel. The silica gel is then dried to remove hydroxyl groups, followed by acid washing to remove impurities, yielding precipitated silica. The main component of the silica precipitation solution and the acid washing solution is aluminum chloride. After adjusting the pH of the silica precipitation solution and the acid washing solution, polyaluminum chloride is obtained through aging, evaporation, and concentration. This invention features a simple process that enables the reuse of silicon and aluminum resources in industrial waste, producing polyaluminum chloride as a byproduct in the production of precipitated silica, resulting in high economic value. Attached Figure Description
[0016] Figure 1 The process flow diagram for preparing silica and polyaluminum chloride from the alkaline leaching residue of silicon-rich aluminum solid waste of the present invention is shown below. Figure 2 The image shows the XRD pattern of the solid polyaluminum chloride prepared in Example 1. Detailed Implementation
[0017] This invention provides a method for preparing silica from alkaline leaching residue of silicon-aluminum rich solid waste, comprising the following steps: 1) The alkaline leaching residue of silicon-aluminum solid waste is mixed with acid for acid leaching to obtain acid leaching solution; 2) After adding alkali to the acid leaching solution to carry out the silica precipitation reaction, the solid and liquid are separated to obtain silica precipitation solution and silica gel; the silica gel is dried and refined to obtain silica powder; 3) After mixing silicon powder and acid for acid leaching, solid-liquid separation is performed to obtain acid leaching solution and solid powder; the solid powder is washed and dried to obtain silica.
[0018] In this invention, the acid in step 1) is preferably hydrochloric acid, and the concentration of hydrochloric acid is preferably 1~4 mol / L, more preferably 2~3 mol / L, and even more preferably 2.5 mol / L; the mass ratio of silicon-aluminum solid waste alkali leaching residue to acid is preferably 1:3~15, more preferably 1:5~12, and even more preferably 1:8~10.
[0019] In this invention, the alkaline leaching residue of silicon-aluminum solid waste is preferably obtained by leaching industrial waste residue with alkali, and the industrial waste residue preferably includes one or more of fly ash, lithium slag and water slag.
[0020] In this invention, the alkali mentioned in step 2) is preferably a sodium hydroxide solution, and the mass fraction of the sodium hydroxide solution is preferably 8-32%, more preferably 15-27%, and even more preferably 20-25%. The endpoint of the silica precipitation reaction is preferably a pH value of 3-3.5, and more preferably 3.2-3.3.
[0021] In this invention, the drying temperature in step 2) is preferably 80~160℃, more preferably 100~140℃, and even more preferably 120~130℃. The D90 of the silicon powder is preferably ≤45μm, and even more preferably ≤40μm.
[0022] In this invention, the acid in step 3) is preferably hydrochloric acid, the concentration of hydrochloric acid is preferably 1.5~3 mol / L, more preferably 2~2.5 mol / L, and the mass ratio of silicon powder to hydrochloric acid is preferably 1:2~4, more preferably 1:2.5~3.5, and more preferably 1:3.
[0023] In this invention, the acid leaching temperature in step 3) is preferably 60~80℃, more preferably 65~75℃, and even more preferably 70℃, and the drying temperature is preferably 150~170℃, more preferably 155~165℃, and even more preferably 160℃.
[0024] In this invention, the silica precipitation solution in step 2) and the acid leaching solution in step 3) are mixed, and the mixture is sequentially adjusted for pH, aged, and concentrated by evaporation to obtain polyaluminum chloride.
[0025] In this invention, the reagent for adjusting the pH value is preferably a sodium hydroxide solution, and the mass fraction of the sodium hydroxide solution is preferably 8-32%, more preferably 12-25%, and even more preferably 15-20%; the pH value is preferably adjusted to 4-5, and even more preferably to 4.5; the aging temperature is preferably 20-80℃, more preferably 40-60℃, and even more preferably 50℃; the aging time is preferably 4-36h, more preferably 8-30h, and even more preferably 15-25h.
[0026] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0027] In the embodiments, lithium slag and fly ash are from Ganfeng Lithium Industry, and water slag is from Xinyu Iron and Steel Group; the alkaline leaching process for obtaining alkaline leaching residue (alkaline leached lithium slag, alkaline leached fly ash, and alkaline leached water slag) from lithium slag, fly ash, and water slag is as follows: a 20% sodium hydroxide solution is mixed with industrial solid waste (lithium slag, fly ash, or water slag) at a liquid-to-solid mass ratio of 2.5:1, and the mixture is subjected to hydrothermal reaction at 220°C for 1 hour, followed by filtration to obtain alkaline leaching residue; The sample preparation machine is an intelligent vibratory mill sample preparation machine, model: RK / 3ZM-100, purchased from Wuhan Locke Grinding Equipment Manufacturing Co., Ltd.
[0028] Example 1
[0029] (1) Mix 50g of alkaline-leached lithium residue with 1mol / L hydrochloric acid at a solid-liquid ratio of 1:15, react at room temperature for 30min, filter and rinse with water to obtain an acid leaching solution rich in silicon and aluminum.
[0030] (2) At room temperature, add 8% NaOH solution to the acid leaching solution to precipitate silicon. The amount of NaOH solution added is to make the pH value of the reaction system 3. A mixture of silicon precipitation solution and silicon gel is obtained. The mixture is filtered to obtain silicon precipitation solution and silicon gel. The silicon gel is dried at 120℃ for 5h and finely ground for 4min using a sample preparation machine to obtain silicon powder with D90≤40μm.
[0031] (3) Mix silicon powder and 3 mol / L hydrochloric acid at a solid-liquid ratio of 1:2, and leach at 60°C for 30 min. Filter to obtain the leaching solution and solid powder. After rinsing the solid powder with water, dry it at 160°C to obtain powdered silica (dry product).
[0032] (4) Mix the silica precipitation solution from step (2) and the acid leaching solution from step (3) to obtain a mixed solution. Adjust the pH of the mixed solution to 4.5 with an 8% NaOH solution. Then, mature the solution at 60°C for 12 hours and evaporate and concentrate it to obtain solid polyaluminum chloride.
[0033] The purity of the powdered silica (dry product) in this embodiment is 91.68%, and the loss on ignition at 1000°C is 4.83%; the mass fraction of alumina in the solid polyaluminum chloride is 29.27%.
[0034] Example 2
[0035] (1) Mix 30g of alkaline leaching residue with 2mol / L hydrochloric acid at a solid-liquid ratio of 1:7.5, react at room temperature for 60min, filter and rinse with water to obtain an acid leaching solution rich in silicon and aluminum.
[0036] (2) At room temperature, add 32% NaOH solution to the acid leaching solution to precipitate silicon. The amount of NaOH solution added is to make the pH value of the reaction system 3.5. A mixture of silicon precipitation solution and silicon gel is obtained. The mixture is filtered to obtain silicon precipitation solution and silicon gel. The silicon gel is dried at 80℃ for 6 hours and finely ground for 3 minutes using a sample preparation machine to obtain silicon powder with D90≤30μm.
[0037] (3) Mix silicon powder and 1.5 mol / L hydrochloric acid at a solid-liquid ratio of 1:4, and leach at 60°C for 30 min. Filter to obtain leaching solution and solid powder. After rinsing the solid powder with water, dry it at 160°C to obtain powdered silica (dry product).
[0038] (4) Mix the silica precipitation solution from step (2) and the acid leaching solution from step (3) to obtain a mixed solution. Adjust the pH of the mixed solution to 4.5 with an 8% NaOH solution. Then, age it at 80°C for 4 hours and evaporate and concentrate it to obtain solid polyaluminum chloride.
[0039] The purity of the powdered silica (dry product) in this embodiment is 90.26%, and the loss on ignition at 1000°C is 5.09%; the mass fraction of alumina in the solid polyaluminum chloride is 31.69%.
[0040] Example 3
[0041] (1) 100g of alkaline-leached fly ash was mixed with 3mol / L hydrochloric acid at a solid-liquid ratio of 1:5. The mixture was reacted at room temperature for 60min, filtered, and rinsed with water to obtain an acid leaching solution rich in silicon and aluminum.
[0042] (2) At room temperature, add 16% NaOH solution to the acid leaching solution to precipitate silicon. The amount of NaOH solution added is to make the pH value of the reaction system 3.5. A mixture of silicon precipitation solution and silicon gel is obtained. The mixture is filtered to obtain silicon precipitation solution and silicon gel. The silicon gel is dried at 160℃ for 4 hours and finely ground for 4 minutes using a sample preparation machine to obtain silicon powder with D90≤40μm.
[0043] (3) Mix silicon powder and 2 mol / L hydrochloric acid at a solid-liquid ratio of 1:3, and leach at 60°C for 30 min. Filter to obtain leaching solution and solid powder. After rinsing the solid powder with water, dry it at 160°C to obtain powdered silica (dry product).
[0044] (4) Mix the silica precipitation solution from step (2) and the acid leaching solution from step (3) to obtain a mixed solution. Adjust the pH of the mixed solution to 4.5 with an 8% NaOH solution. Then, mature the solution at 20°C for 36 hours and evaporate and concentrate it to obtain solid polyaluminum chloride.
[0045] The purity of the powdered silica (dry product) in this embodiment is 92.47%, and the loss on ignition at 1000°C is 3.81%; the mass fraction of alumina in the solid polyaluminum chloride is 28.43%.
[0046] Example 4
[0047] (1) 200g of alkaline-leached lithium residue was mixed with 4mol / L hydrochloric acid at a solid-liquid ratio of 1:3.5 and reacted at room temperature for 20min. The mixture was then filtered and rinsed with water to obtain an acid leaching solution rich in silicon and aluminum.
[0048] (2) At room temperature, add 32% NaOH solution to the acid leaching solution to precipitate silicon. The amount of NaOH solution added is to make the pH value of the reaction system 3. A mixture of silicon precipitation solution and silicon gel is obtained. The mixture is filtered to obtain silicon precipitation solution and silicon gel. The silicon gel is dried at 100℃ for 4 hours and finely ground for 6 minutes using a sample preparation machine to obtain silicon powder with D90≤35μm.
[0049] (3) Mix silicon powder and 3 mol / L hydrochloric acid at a solid-liquid ratio of 1:2, and leach at 80°C for 30 min. Filter to obtain the leaching solution and solid powder. After rinsing the solid powder with water, dry it at 160°C to obtain powdered silica (dry product).
[0050] (4) Mix the silica precipitation solution from step (2) and the acid leaching solution from step (3) to obtain a mixed solution. Adjust the pH of the mixed solution to 4.5 with a 32% NaOH solution. Then, mature the solution at 60°C for 8 hours and evaporate and concentrate it to obtain solid polyaluminum chloride.
[0051] The purity of the powdered silica (dry product) in this embodiment is 89.44%, and the loss on ignition at 1000°C is 6.39%; the mass fraction of alumina in the solid polyaluminum chloride is 30.13%.
[0052] This invention provides a method for preparing precipitated silica from alkaline leaching residue of silicon-aluminum-rich solid waste. The method involves acid leaching the residue after alkaline leaching with hydrochloric acid to obtain an acid leaching solution rich in silicon and aluminum. The pH of the acid leaching solution is adjusted with sodium hydroxide solution to obtain an aluminum-rich silica precipitation solution and silica gel. The silica gel is dried, ground, and then purified with acid to increase the specific surface area of the precipitated silica. The mixture of the purified precipitated silica acid solution and the silica precipitation solution is then adjusted to pH and matured to directly obtain liquid polyaluminum chloride. The liquid polyaluminum chloride can be evaporated and concentrated to obtain solid polyaluminum chloride. This method is simple, uses inexpensive equipment, and has a short operation process. The prepared precipitated silica meets the requirements of HG / T 3061-2020, and the byproduct polyaluminum chloride meets the requirements of GB / T 22627-2022. Furthermore, the raw materials are recycled industrial waste, which is in line with the concept of green development.
[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing silica from alkaline leaching residue of silicon-aluminum rich solid waste, characterized in that, It includes the following steps: 1) The alkaline leaching residue of silicon-aluminum solid waste is mixed with acid for acid leaching to obtain acid leaching solution; 2) After adding alkali to the acid leaching solution to carry out the silica precipitation reaction, the solid and liquid are separated to obtain silica precipitation solution and silica gel; the silica gel is dried and refined to obtain silica powder; 3) After mixing silicon powder and acid for acid leaching, solid-liquid separation is performed to obtain acid leaching solution and solid powder; the solid powder is washed and dried to obtain silica.
2. The method according to claim 1, characterized in that, Step 1) The acid is hydrochloric acid, and the concentration of hydrochloric acid is 1~4 mol / L; the mass ratio of the alkaline leaching residue of silicon-aluminum solid waste to acid is 1:3~15.
3. The method according to claim 1 or 2, characterized in that, The silicon-aluminum-rich solid waste alkali leaching residue is obtained by leaching industrial waste residue with alkali. The industrial waste residue includes one or more of fly ash, lithium slag and water slag.
4. The method according to claim 3, characterized in that, Step 2) The alkali is a sodium hydroxide solution with a mass fraction of 8-32%, and the endpoint of the silica precipitation reaction is the pH value of the reaction system being 3-3.
5.
5. The method according to claim 4, characterized in that, Step 2) The drying temperature is 80~160℃, and the D90 of the silicon powder is ≤45μm.
6. The method according to claim 4 or 5, characterized in that, Step 3) The acid is hydrochloric acid, with a concentration of 1.5~3 mol / L, and the mass ratio of silicon powder to hydrochloric acid is 1:2~4.
7. The method according to claim 6, characterized in that, Step 3) The acid leaching temperature is 60~80℃, and the drying temperature is 150~170℃.
8. The method according to claim 7, characterized in that, The silica precipitation solution in step 2) and the acid leaching solution in step 3) are mixed, and the mixture is sequentially adjusted for pH, aged, and concentrated by evaporation to obtain polyaluminum chloride.
9. The method according to claim 8, characterized in that, The pH value was adjusted using sodium hydroxide solution to a value of 4-5. The aging temperature was 20-80℃ and the aging time was 4-36 hours.