Method for hydrothermal synergistic treatment and resource utilization of brown corundum dust and carbide slag

Abstract

The application discloses a method for hydrothermal synergic treatment and resource utilization of brown corundum dust and carbide slag, and belongs to the technical field of solid waste resource recovery. The application takes brown corundum dust and carbide slag as raw materials, adds caustic solution to strengthen calcification leaching reaction, separates liquid and solid after the reaction is completed, and the filter cake is silicon fertilizer; the leaching filtrate is subjected to carbonation precipitation to obtain a gallium-containing product, the carbonation solution is recycled after causticization, and potassium in the brown corundum dust enters the leaching solution, so that new alkali does not need to be supplemented in the recycling. The application adopts the idea of 'waste treatment with waste', fully utilizes the silicon-calcium synergic strengthening reaction effect of the brown corundum dust and the carbide slag, and realizes resource utilization and zero emission of the two types of solid wastes.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource recovery, and in particular relates to a method for zero-emission resource recovery by hydrothermal coordinated treatment of brown corundum dust removal ash and carbide slag. Background Art

[0002] Brown corundum has the advantages of high hardness, strong wear resistance and good thermal stability. It is widely used in the processing and polishing of materials such as metals, ceramics, and glass. It is an indispensable basic material in the fields of abrasives, grinding tools, and refractory materials. However, the smelting process of brown corundum not only consumes a large amount of electricity, but also produces a large amount of difficult-to-handle brown corundum dust, which not only restricts the development of the brown corundum industry but also causes serious damage to the environment. However, due to the extremely high temperature required for the smelting process of brown corundum (about 2200℃), in addition to being rich in SiO2 and Al2O3, brown corundum dust also enriches most of the low-boiling point metal oxides such as K and Ga in the raw materials, making it an important potential resource for obtaining potassium and gallium. Given the unsustainable nature of the brown corundum industry and the importance of Ga and K resources, it is also of great significance to achieve green and large-scale consumption of brown corundum dust while achieving efficient extraction and recovery of Ga and K resources.

[0003] Currently reported treatment methods for brown corundum dust removal ash can be mainly divided into two categories: acid method and acid-base combined method. Although efficient leaching of Ga can be achieved, the acid and alkali used in the reaction process are difficult to recycle and a large amount of acid-containing waste liquid is generated. At the same time, due to poor leaching selectivity, a large amount of impurities enter the leachate together with Ga, which also brings difficulties to the subsequent extraction and separation of Ga. In addition, current processes focus more on the extraction of gallium from brown corundum dust removal ash, while there is less research on the extraction and utilization of coexisting resources such as K and Si. Summary of the Invention

[0004] In order to overcome the shortcomings of the acid method and the acid-base combined method in the treatment of brown corundum dust ash, such as the inability to circulate the reaction medium, poor component leaching selectivity, and difficulty in subsequent separation and extraction, the present invention proposes a method for the hydrothermal synergistic treatment of brown corundum dust ash and carbide slag to achieve zero-emission resource utilization. Brown corundum dust ash and carbide slag are synergistically treated to produce silicon fertilizer while recovering Ga and K. This process uses carbide slag as a cheap calcium source, and gradually extracts and recovers valuable components from brown corundum dust ash through the steps of calcification leaching, carbonation precipitation, and alkali solution regeneration, and converts the SiO2 therein into effective SiO2 that can be absorbed by plants, so as to be used as silicon fertilizer in agricultural production. The regenerated alkali solution can be reused for the treatment of brown corundum dust ash, and no waste residue or wastewater is generated during the reaction process.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for resource-based zero-emission hydrothermal synergistic treatment of brown corundum dust and carbide slag comprises the following steps: using brown corundum dust and carbide slag as raw materials, adding a caustic soda solution to strengthen the calcification leaching reaction, separating the liquid and solid after the reaction is completed, and obtaining a filter cake as silicon fertilizer; obtaining a gallium-containing product through a carbonation precipitation reaction of the leaching filtrate, and recycling the carbonated solution after causticization, thereby achieving zero waste emission.

[0007] The relationship between the Gibbs free energy and temperature of the reactions that may occur during the calcification leaching process was calculated using HSC Chemical 10.3.4 software. The results are shown in Figure (1). Under the action of alkali solution, the silicon-containing and aluminum-containing components (such as SiO2, Al2O3, KAlSi3O8, Al2SiO5 and Ga(OH)3) in the brown corundum dust removal are first decomposed into H4SiO4 and Al(OH)3, and K and Ga are respectively converted into K + and Ga(OH)4 - Enters into the alkali solution in the form of (Formula (1)-(5), Figure 1 a). However, Al(OH)3 and H4SiO4 are not stable in alkali solution and will further react with OH in alkali solution. - Reaction to generate Al(OH)4 - 、H3SiO4 - 、H2SiO4 2- 、HSiO4 3- and SiO4 4- (Formula (6)-(10), Figure 1 b). Without adding other components, as the concentration of aluminate ions and orthosilicate ions in the alkali solution increases, gelation will further occur. The generated gel will be deposited on the surface of the brown corundum to form a coating, hindering the continuation of the reaction.

[0008] SiO2(s)+2OH - (aq)+2H + (aq)=H4SiO4(aq) (1)

[0009] Al2O3(s)+3OH - (aq)+3H + (aq)=2Al(OH)3(aq) (2)

[0010] KAlSi3O8(s)+7OH - (aq)+8H + (aq) = K + (aq)+Al(OH)3(aq)+3H4SiO4(aq) (3)

[0011] Al2SiO5(s)+5OH -(aq) + 5H + (aq) = 2Al(OH)3(aq) + H4SiO4(aq) (4)

[0012] Ga(OH)3(s) + OH - (aq) = Ga(OH)4 - (aq) (5)

[0013] Al(OH)3(aq) + OH - (aq) = Al(OH)4 - (aq) (6)

[0014] H4SiO4(aq) + OH - (aq) = H3SiO4 - (aq) + H2O (I) (7)

[0015] H3SiO4 - (aq) + OH - (aq) = H2SiO4 2- (aq) + H2O (I) (8)

[0016] H2SiO4 2- (aq) + OH - (aq) = HSiO4 3- (aq) + H2O (I) (9)

[0017] HSiO4 3- (aq) + OH - (aq) = SiO4 4- (aq) + H2O (I) (10)

[0018] When calcium carbide slag is added into lye (no caustic alkali is added because the solubility of Ca(OH)2 in water is low, which will cause slow and incomplete reaction. Therefore, no caustic alkali can also be added in the present application), the calcium carbide slag will first react with water to generate Ca 2+ and OH - , which is limited by the low solubility of Ca 2+ in lye. The dissolved Ca 2+ and OH - will combine again to generate Ca(OH)2 (formula (11)-(12), Figure 1 c) in the calcification leaching process. Ca(OH)2 can not only react with free silicate in the solution to generate stable Ca2SiO4 and other calcium silicate compounds to inhibit the progress of gelation reaction, but also release OH - into lye, thereby further promoting the reaction of lye and brown corundum dust (formula (13)-(17), Figure 1 d) in the presence of calcium carbonate. Addition of carbide slag can greatly reduce the required caustic content in the solution.

[0019] CaO(s) + H2O(I) = Ca 2+ (aq) + 2OH - (aq) (11)

[0020] Ca 2+ (aq) + 2OH - (aq) = Ca(OH)2(s) (12)

[0021] 2Ca(OH)2(s) + H4SiO4(aq) = Ca2SiO4(s) + 4H2O(I) (13)

[0022] 2Ca(OH)2(s) + H3SiO4 - (aq) = Ca2SiO4(s) + 3H2O(I) + OH - (aq) (14)

[0023] 2Ca(OH)2(s) + H2SiO4 2- (aq) = Ca2SiO4(s) + 2H2O(I) + 2OH - (aq) (15)

[0024] 2Ca(OH)2(s) + HSiO4 3- (aq) = Ca2SiO4(s) + H2O(I) + 3OH - (aq) (16)

[0025] 2Ca(OH)2(s) + SiO4 4- (aq) = 2Ca2SiO4(s) + 4OH - (aq) (17)

[0026] The main ions in the calcified leaching solution are OH - , Al(OH)4 - and Ga(OH)4 - . Although Ga in the brown corundum dust enters the solution, the concentration is still difficult to meet the requirements of the currently industrialized resin adsorption separation, and further enrichment is needed. Carbonation precipitation is to use CO2 to dissolve in the alkali solution, reduce the pH value of the solution, and make the aluminum and gallium in the solution co-precipitate and precipitate out, and the main reactions are shown as formulas (18)-(20).

[0027] OH - (aq) + CO2(g) = HCO3 - (aq) (18)

[0028] Al(OH)4 - (aq) + CO2(g) = Al(OH)3(s) + HCO3 - (aq) (19)

[0029] Ga(OH)4 - (aq) + CO2(g) = Ga(OH)3(s) + HCO3 - (aq) (20)

[0030] The main components of the filtrate after carbonation are H2CO3, HCO3 - and CO3 2- , add carbide slag to the carbonated solution, and through a simple causticization reaction (Formula (21)-(23)), the CO2 in the carbonated solution can be removed, and the regenerated alkali solution can be reused to treat brown corundum dust and carbide slag.

[0031] CO3 2- (aq)+Ca(OH)2(s)=CaCO3(s)+2OH - (aq) (21)

[0032] HCO3 - (aq) + Ca(OH)2(s) = CaCO3(s) + OH - (aq)+H2O(I) (22)

[0033] H2CO3(aq)+Ca(OH)2(s)=CaCO3(s)+2H2O(I) (23)

[0034] Preferably, the brown corundum dust ash and carbide slag are mixed in a ratio of Ca / Si in the system of 0.6-1.5.

[0035] Preferably, the liquid-to-solid ratio of the caustic soda solution to the raw material is 5-40 mL / g.

[0036] More preferably, the caustic soda solution is sodium hydroxide or potassium hydroxide with a concentration of 0-80 g / L. A concentration of 0 means that no caustic soda solution is added and an equal volume of deionized water is used instead.

[0037] Preferably, the calcification leaching reaction is carried out at 120-240° C. for 30-180 minutes.

[0038] Preferably, during the carbonation precipitation process, the end point pH is controlled to be 7.0-9.0, the carbonation temperature is room temperature-100° C., and the time is 20-150 min.

[0039] Preferably, during the causticizing reaction, the carbonation filtrate and carbide slag are used as raw materials, the causticizing temperature is room temperature-100° C., and the time is 30-90 min.

[0040] More preferably, the carbonation filtrate and carbide slag are mixed in a molar ratio of Ca to K / Na of 0.9-1.5.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] The present invention's treatment process is clean and energy-efficient, enabling full resource utilization of brown corundum dust and carbide slag. It effectively recovers Ga and K from the brown corundum dust and converts Si into effective silicon that can be absorbed by plants. The method simultaneously addresses the pollution problems associated with the accumulation of brown corundum dust and carbide slag, and provides a valuable reference for the coordinated, high-value utilization of multiple solid wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0044] Figure 1 The relationship between Gibbs free energy of possible reactions during calcification leaching and temperature;

[0045] Figure 2 It is a schematic diagram of the process of the present invention;

[0046] Figure 3 This is a physical picture of the calcified leaching residue obtained in the method of Example 1 of the present invention;

[0047] Figure 4 The effective SiO2, effective CaO, effective K2O and leaching pH value in the brown corundum dust removal ash, carbide slag and calcified leaching residue in the method of Example 1 of the present invention;

[0048] Figure 5 This is a photo of the gallium aluminum carbonation precipitation in the method of Example 1 of the present invention;

[0049] Figure 6 The changes in Ga and Al concentrations in the solution before and after carbonation precipitation and the carbonation precipitation efficiency in the method of Example 1 of the present invention are shown;

[0050] Figure 7 It is the causticizing efficiency and the loss efficiency of Ga in the alkali solution regeneration process in the method of Example 1 of the present invention. DETAILED DESCRIPTION

[0051] Various exemplary embodiments of the present application will now be described in detail, with reference to the figures. These embodiments are described herein for illustrative purposes only and are not intended to limit the scope of the application, which is defined by the appended claims as interpreted in light of the full written disclosure and its equivalents.

[0052] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. In addition, where particular ranges of values are given, understand that each intervening value, to the upper or lower limit of the ranges is also specifically included. Each smaller range that falls within the broader ranges is also specifically included in the present application. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0053] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the patents, patent applications, publications, and descriptions are cited.

[0054] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof. Other implementations of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The examples and embodiments described herein are exemplary only and are not intended to be limiting.

[0055] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having" and the like are open-ended terms that are intended to permit but not limit the inclusion of elements or the number of elements, and that do not on their own recite a complete list of elements or method steps.

[0056] As used herein, the term "room temperature" means 25°C, unless otherwise specified.

[0057] The starting materials used in the following examples of the present application are commercially available.

[0058] The present invention discloses a method for synergistically treating brown corundum dust removal ash and carbide slag and achieving zero waste discharge, which belongs to the technical field of solid waste resource recovery. It mainly comprises the following steps: mixing brown corundum dust removal ash, carbide slag and a certain concentration of KOH or NaOH solution, stirring evenly, reacting under closed conditions to obtain a filtrate and a solid product. The filtrate is further separated by carbonation precipitation to obtain a gallium-containing product. A certain amount of carbide slag is added to the carbonated alkali solution, and the alkali solution can be regenerated through a causticization reaction. The solid product obtained in the calcification leaching process can be used as silicon fertilizer in agricultural production after washing and drying. The present invention adopts the research idea of ​​"treating waste with waste", realizes the full resource utilization of brown corundum dust removal ash and carbide slag, and efficiently recovers Ga and K in brown corundum smoke, which is of great significance to the high-value utilization of brown corundum smoke and carbide slag. The specific technical scheme is as follows:

[0059] The invention provides a method for resource-based zero-emission hydrothermal synergistic treatment of brown corundum dust and carbide slag. The method comprises the following steps: uniformly mixing brown corundum dust, carbide slag and a certain concentration of KOH or NaOH solution, and then transferring the mixture to a closed reactor for reaction for a certain period of time. After the reaction is completed, the solid product and the filtrate are filtered and separated. The solid product can be used as silicon fertilizer in agricultural production after washing and drying. The filtrate is subjected to carbonation precipitation and then filtered and separated to obtain a gallium-containing product and a carbonated alkali solution. A certain amount of carbide slag is added to the carbonated alkali solution for causticization reaction, thereby regenerating the alkali solution. The causticized slag can be reused after being regenerated by roasting.

[0060] In some preferred embodiments of the present invention, the Ca / Si molar ratio in the co-processing system is 0.6-1.5, preferably 0.9; the concentration of the KOH solution or NaOH solution is 0-80 g / L, preferably 10 g / L. During the specific reaction process, the amount of brown corundum dust is fixed, and the Ca / Si molar ratio in the system is adjusted by adjusting the amount of carbide slag.

[0061] In some preferred embodiments of the present invention, the leaching temperature is 120-240° C., preferably 180° C., and the leaching time is 30-180 min, preferably 120 min.

[0062] In some preferred embodiments of the present invention, in the co-processing system, the liquid-to-solid ratio of KOH or NaOH solution to raw materials (brown corundum dust and carbide slag) is 5-40 mL / g, preferably 20 mL / g.

[0063] In some preferred embodiments of the present invention, during the carbonation precipitation process of the filtrate, the endpoint pH is controlled to be 8.0-9.0 (cooled to room temperature), the carbonation temperature is room temperature-100°C, preferably 90°C, and the time is 20-150 min, preferably 60 min.

[0064] In some preferred embodiments of the present application, the molar ratio of Ca / K or Na in the causticization process is 0.9-1.5, preferably 1.2; the causticization temperature is room temperature-100℃, preferably room temperature, and the time is 30-90min, preferably 60min.

[0065] The following examples are further illustrations of the technical solutions of the present application.

[0066] Example 1

[0067] The brown corundum dust ash used in this example was obtained from a brown corundum abrasive factory, and the carbide slag was obtained from an acetylene gas production factory. The chemical compositions are shown in Table 1.

[0068] Table 1 Main element contents (wt.%) of brown corundum dust ash and carbide slag

[0069] type Si Al K Ca Fe Na Ti Mn Ga Brown corundum dust removal ash 27.78 9.22 11.02 0.08 1.54 0.67 0.2 0.25 0.117 carbide slag 1.33 0.33 — 63.97 0.21 0.16 — — —

[0070] The test process of the present application mainly includes three main processes of calcification leaching, carbonation precipitation and lye regeneration. The process schematic diagram is shown in Figure 2 .

[0071] Calcification leaching method and effect: 6.0g of brown corundum dust ash was weighed, and carbide slag was added according to the Ca / Si molar ratio of 0.9, and 180mL of 10g / L KOH solution was added into the reactor, and then stirred uniformly, and reacted at 180℃ for 120min. When the temperature decreased to 80-90℃, filtration separation was carried out, and the filter cake was the silicon fertilizer. The filtrate was used for subsequent gallium extraction. The extraction efficiency of Ga and K was calculated by formula (24), and the extraction efficiency of Ga and K was 94.02% and 85.32% respectively. The effective SiO2, effective K2O, effective CaO in the solid sample and the leaching pH value were analyzed according to the standards of NY / T2272-2012, NYT2273-2012 and HJ557-2010. Figure 3 The physical map of the calcification leaching residue is shown in Figure 4 Table 2 Main chemical components of the calcification leaching residue, wherein the effective SiO2 and effective CaO are 34.71wt.% and 33.02wt.% respectively, which meet the silicon fertilizer standard.

[0072] Table 2 Main element contents (wt.%) of the calcification residue and carbonation precipitation of Ga and Al

[0073]

[0074]

[0075] Wherein, η1 is the extraction efficiency of Ga or K (%); m0 and m1 are the masses (g) of brown corundum dust ash and calcified leaching residue, respectively; ω0 and ω1 are the contents (wt.%) of Ga or K in brown corundum dust ash and calcified leaching residue, respectively.

[0076] Carbonation precipitation process: 150mL of calcified leaching filtrate was measured and placed in a reactor. CO2 was introduced at 90°C and the pressure was maintained at 1.5MPa for 60 minutes. When the pH value dropped to 7.0-9.0, the pressure was released, the liquid and solid were separated, and the filtrate was recycled. The carbonation precipitation efficiency of Ga and Al in the solid was calculated using formula (25). The carbonation precipitation rates of Ga and Al were 97.70% and 99.89%, respectively. The Al and Ga contents in the precipitated solid were 32.99wt.% and 2.1429wt.%, respectively (Table 2). The Ga content was 18.3 times higher than that of the dust ash. See the actual picture. Figure 5 As shown, Figure 6 Figure 3 shows the concentration changes of Ga and Al in the solution before and after carbonation and the carbonation precipitation efficiency, which shows the high extraction of Ga and Al.

[0077]

[0078] Wherein, η2 is the carbonation precipitation efficiency of Ga or Al (%); c2 and c3 are the contents of Ga or Al in the solution before and after carbonization (mg / L), respectively; V2 and V3 are the volumes of the solution before and after carbonization (L), respectively.

[0079] Alkali liquor regeneration process: 100 mL of the filtrate after carbonation precipitation was placed in a stoppered bottle and causticized by adding carbide slag at a Ca / K molar ratio of 1.2. The causticization temperature was 25°C and the reaction time was 60 min. The alkali concentration of the causticized solution was measured and the causticization rate was calculated using formula (26). The causticization rate of the solution was 98.66%. The loss rate of Ga during the alkali liquor regeneration process was calculated using formula (27): Figure 7 is the causticizing efficiency and the loss rate of Ga during the alkali solution regeneration process. There is almost no loss of Ga during the causticizing process, and the causticizing efficiency increases with the increase of the Ca / K molar ratio.

[0080]

[0081] Wherein, η3 is the causticizing efficiency (%); V4 and V5 are the volumes (mL) of standard hydrochloric acid consumed in the determination of total alkali and carbon alkali, respectively.

[0082]

[0083] Wherein, η4 is the loss rate of Ga during the causticizing process (%); c4 and c5 are the Ga contents in the solution before and after the causticizing reaction (g / L), respectively; V6 and V7 are the volumes of the solution before and after the causticizing reaction (L), respectively.

[0084] Example 2

[0085] The same as Example 1, except that during the calcification leaching process, the amount of carbide slag added was in accordance with the Ca / Si molar ratio of 0.7, 0.8, 1.0, 1.2, and 1.5. The results are shown in Table 3.

[0086] Table 3 Effect of Ca / Si molar ratio on Ga and K leaching efficiency

[0087] Ca / Si molar ratio Ga leaching efficiency / % K leaching efficiency / % 0.7 85.41 74.51 0.8 90.89 80.75 1.0 92.02 87.74 1.2 85.43 88.94 1.5 80.67 90.64

[0088] It can be found from Table 3 that the leaching efficiency of Ga first increases and then decreases with the increase of Ca / Si molar ratio; the leaching efficiency of K gradually increases with the increase of Ca / Si molar ratio.

[0089] Example 3

[0090] The same as Example 1, except that during the calcification leaching process, the leaching temperatures were 150° C., 160° C., 170° C., 200° C., and 220° C. The results are shown in Table 4.

[0091] Table 4 Effect of leaching temperature on Ga and K leaching efficiency

[0092]

[0093]

[0094] It can be found from Table 4 that the leaching efficiency of Ga and Al gradually increases with the increase of Ca / Si molar ratio. When the leaching temperature exceeds 180 °C, further increasing the temperature has little effect on the leaching efficiency of Ga and K.

[0095] Example 4

[0096] The same as Example 1, except that the leaching time during the calcification leaching process was 60 min, 80 min, 100 min, 140 min, 160 min, and 180 min, respectively. The results are shown in Table 5.

[0097] Table 5 Effect of leaching time on Ga and K leaching efficiency

[0098] Leaching time / min Ga leaching efficiency / % K leaching efficiency / % 60 74.89 69.37 80 84.29 76.48 100 88.37 79.64 140 94.17 85.64 160 94.73 85.81 180 94.32 86.07

[0099] It can be found from Table 5 that the leaching efficiency of Ga and Al gradually increases with the increase of Ca / Si molar ratio. When the time exceeds 120 min, the leaching efficiency of Ga and K basically does not change as time continues to extend.

[0100] Example 5

[0101] The same as Example 1, except that deionized water is added instead of KOH solution during the calcification leaching process. Specifically: 6.0g of brown corundum dust removal ash is weighed, and carbide slag is weighed according to the ratio of Ca / Si molar ratio of 0.9 in the system. The brown corundum dust removal ash and carbide slag are added together with 180mL of deionized water, and after continuous stirring for 30min at room temperature, they are transferred to a monomer-type high-pressure reactor and reacted at 180°C for 120min. After the reaction is completed, cooling water is passed through for cooling. When the temperature is reduced to the range of 80-90°C, the filtrate and filter cake are separated by filtration.

[0102] In the filtrate obtained by the method of this embodiment, the leaching efficiency of Ga is 72.57%, and the leaching efficiency of K is 75.37%. This is because the solubility of calcium carbide slag in deionized water is low and the alkalinity of the solution is weak, resulting in incomplete reaction of the calcification leaching process.

[0103] Example 6

[0104] The same as Example 1, except that during the calcification leaching process, the KOH solution is replaced by a sodium hydroxide solution.

[0105] In the filtrate obtained by the method of this embodiment, the extraction efficiency of Ga was 95.09%, and the extraction efficiency of K was 91.35%.

[0106] Example 7

[0107] The same as Example 1, except that, during the calcification leaching process, the solid-to-liquid ratios of the raw materials (brown corundum dust and carbide slag) to the caustic solution (KOH solution) were 10 mL / g, 15 mL / g, 25 mL / g, and 30 mL / g, respectively, and the amount of KOH solution added was changed to 90 mL, 135 mL, 225 mL, and 270 mL, respectively. The results are shown in Table 6.

[0108] Table 6 Effect of solid-liquid ratio on Ga and K leaching efficiency

[0109] Solid-liquid ratio Ga leaching efficiency / % K leaching efficiency / % 10 91.03 79.41 15 92.47 83.14 25 94.16 86.03 30 94.33 86.51

[0110] It can be found from Table 6 that the leaching efficiency of G and K gradually increases with the increase of liquid-solid ratio. When the liquid-solid ratio is higher than 20 mL / g, the leaching efficiency of Ga and K remains basically unchanged if the liquid-solid ratio continues to increase.

[0111] Comparative Example 1

[0112] The same as Example 1, except that, during the calcification leaching process, the amount of carbide slag added is added at a Ca / Si molar ratio of 2.0.

[0113] In the filtrate obtained by the comparative example method, the leaching efficiency of Ga is 44.26%, and the leaching efficiency of K is 93.14%. The leaching efficiency of Ga is higher, but the leaching efficiency of Ga, which has a higher strategic value, is only 44.26%.

[0114] Comparative Example 2

[0115] The same as Example 1, except that, during the calcification leaching process, the solid-to-liquid ratio of the raw materials (brown corundum dust ash and carbide slag) to the caustic soda solution (KOH solution) is 3 mL / g.

[0116] In the filtrate obtained by the method of this comparative example, the leaching efficiency of Ga was 68.74%, and the leaching efficiency of K was 53.49%.

[0117] Comparative Example 3

[0118] The same as Example 1, except that the leaching temperature during the calcification leaching process is 90°C.

[0119] In the filtrate obtained by the comparative example method, the leaching efficiency of Ga is 43.70%, and the leaching efficiency of K is 66.24%. The low leaching temperature cannot effectively destroy the structure of the brown corundum dust.

[0120] Comparative Example 4

[0121] The same as Example 1, except that, during the calcification leaching process, the leaching time is 10 minutes.

[0122] In the filtrate obtained by the comparative example method, the leaching efficiency of Ga is 30.45%, the leaching efficiency of K is 42.87%, the leaching time is short, and the calcium carbide slag and brown corundum dust have not yet completely reacted.

[0123] Comparative Example 5

[0124] Same as Example 1, except that during the calcification leaching process, the concentration of the KOH solution is 120 g / L.

[0125] In the filtrate obtained by the comparative example method, the leaching efficiency of Ga is 95.21%, and the leaching efficiency of K is 84.36%. Although the high concentration of KOH solution does not affect the leaching of Ga and K, it will increase the cost of the subsequent carbonation precipitation and alkali solution regeneration process.

[0126] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for resource-based zero-emission hydrothermal synergistic treatment of brown corundum dust and carbide slag, characterized in that: The method comprises the following steps: using brown corundum dust and carbide slag as raw materials, adding caustic soda solution to intensify the calcification leaching reaction; after the reaction is completed, liquid and solid are separated, and the filter cake is silicon fertilizer; the leaching filtrate is subjected to carbonation precipitation to obtain a gallium-containing product; the carbonation solution is causticized and then recycled, thereby achieving zero waste discharge; The brown corundum dust and carbide slag are mixed in a ratio of 0.6-1.5 in a Ca / Si molar ratio in the system; The liquid-to-solid ratio of the caustic soda solution to the raw material is 5-40 mL / g; The calcification leaching reaction is carried out at 120-240° C. for 30-180 minutes.

2. The method for resource-based zero-emission hydrothermal synergistic treatment of brown corundum dust and carbide slag according to claim 1, characterized in that: The caustic soda solution is a sodium hydroxide solution or a potassium hydroxide solution with a concentration of 0-80 g / L. A concentration of 0 indicates that no caustic soda solution is added and an equal volume of deionized water is used instead.

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