Bayer process red mud dealkalization method

Abstract

The invention relates to a Bayer process red mud dealkalization method, which comprises: adding a dealkalization seed crystal and an auxiliary agent into Bayer process red mud raw stock to dealkalize the Bayer process red mud raw stock to obtain dealkalized red mud slurry; wherein the auxiliary agent comprises a catalytic auxiliary agent with a viscosity reduction effect and a dealkalization auxiliary agent, and the dealkalization auxiliary agent comprises at least one of the following raw material components: calcium hydroxide and calcium oxide. According to the Bayer process red mud dealkalization method provided by the invention, under the synergistic effect of the catalytic promoter with a viscosity reduction effect, the dealkalization promoter containing calcium hydroxide and / or calcium oxide and the dealkalization seed crystal, and by matching with mild dealkalization temperature and relatively short dealkalization time, the purpose of improving the dealkalization efficiency of the Bayer process red mud primary pulp is achieved; and the dealkalization rate reaches 75% or above.

Description

Technical Field

[0001] The present application relates to the technical field of Bayer process red mud, and in particular to a method for dealkalization of Bayer process red mud. Background Art

[0002] Red mud is a waste product produced during the process of refining alumina from bauxite. In the existing red mud recovery of sodium oxide (de-alkali) technology, in addition to the conventional water washing recovery of sodium oxide method, lime recovery of sodium oxide method, sintering method, seawater neutralization method, gypsum recovery of sodium oxide method, acid gas neutralization method and biological recovery of sodium oxide method are all relevant applications.

[0003] However, the existing red mud recovery of sodium oxide (de-alkali) process time is relatively long, and the recovery efficiency of sodium oxide (de-alkali) is low and the cost is high. Summary of the invention

[0004] The present application provides a method for dealkalization of red mud by the Bayer process to solve the following technical problem: how to improve the efficiency of dealkalization of red mud by the Bayer process.

[0005] In a first aspect, the present application provides a method for dealkalization of Bayer process red mud, the method comprising:

[0006] Adding dealkalization seed crystals and auxiliary agents into Bayer process red mud slurry to dealkalize the Bayer process red mud slurry to obtain dealkalized red mud slurry; wherein the auxiliary agents include: a catalytic auxiliary agent with viscosity reduction effect and a dealkalization auxiliary agent, and the raw material components of the dealkalization auxiliary agent include at least one of the following: calcium hydroxide and calcium oxide.

[0007] Optionally, the catalytic aid includes at least one of the following: chlorides and sulfates.

[0008] Optionally, the chloride salt includes at least one of the following: calcium chloride, ferric chloride, and sodium chloride.

[0009] Optionally, the sulfate includes at least one of the following: iron sulfate, calcium sulfate, and sodium sulfate.

[0010] Optionally, the weight of the catalytic promoter is 0.5% to 5% of the weight of the sodium oxide in the Bayer process red mud.

[0011] Optionally, the dealkalizing seed crystals include at least one of the following: sodium silicate, calcium aluminate, calcium aluminosilicate, sintered red mud, and silicate cement.

[0012] Optionally, the weight of the dealkalization seed crystals is 0.5% to 5% of the weight of the Bayer process red mud.

[0013] Optionally, the dealkalization aid includes at least one of the following: quicklime, lime milk, slaked lime, and carbide slag.

[0014] Optionally, the concentration of the Bayer process red mud slurry is 100 g / L to 500 g / L.

[0015] Optionally, the process parameters of dealkalization include: dealkalization temperature of 60°C to 70°C, and dealkalization time of 0.1h to 0.5h.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0017] The Bayer red mud dealkalization method provided in the embodiment of the present application includes adding dealkalization seeds and an auxiliary agent to the Bayer red mud slurry to dealkalize the Bayer red mud slurry to obtain a dealkalized red mud slurry; wherein the auxiliary agent includes: a catalytic auxiliary agent with a viscosity reducing effect and a dealkalization auxiliary agent, and the raw material components of the dealkalization auxiliary agent include at least one of the following: calcium hydroxide and calcium oxide. The sodium in the red mud in the Bayer red mud slurry mainly exists in the form of the chemical formula Na2O·Al2O3·2Si2O, and Na2O·Al2O3·2Si2O reacts with the dealkalization auxiliary agent containing calcium hydroxide and / or calcium oxide to achieve Ca 2+ The Na in the Bayer red mud pulp + The alkali-free reaction product is replaced to generate CaO·3Al2O3·xSi2O and sodium hydroxide; the catalytic promoter with viscosity-reducing effect can reduce the viscosity of the dealkalization reaction solution system and regulate the contact area of ​​the reactants, thereby increasing the dealkalization rate (generating sodium hydroxide) and reducing the dealkalization reaction time, thereby reducing energy consumption; the dealkalization seed can play a role in guiding the crystal lattice of the reaction product, thereby accelerating the dealkalization reaction and improving the dealkalization efficiency. In summary, under the synergistic effect of the catalytic promoter with viscosity-reducing effect, the dealkalization promoter containing calcium hydroxide and / or calcium oxide, and the dealkalization seed, the purpose of improving the dealkalization efficiency of the Bayer process red mud slurry is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 A schematic flow chart of a Bayer process red mud dealkalization method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0023] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the specification of the present application, the terms "include", "comprise", etc. refer to "including but not limited to". In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all represent: a, b, c, ab (i.e., a and b), ac, bc or abc, where a, b, c can be single or multiple, respectively.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0025] In a first aspect, the present application provides a method for dealkalization of Bayer red mud. Figure 1 For a schematic diagram of a Bayer process red mud dealkalization method provided in an embodiment of the present application, please refer to Figure 1, the method comprising:

[0026] S1. Adding dealkalization seed crystals and an auxiliary agent into a Bayer process red mud slurry to dealkalize the Bayer process red mud slurry to obtain a dealkalized red mud slurry; wherein the auxiliary agent comprises: a catalytic auxiliary agent with a viscosity reducing effect and a dealkalization auxiliary agent, and the raw material components of the dealkalization auxiliary agent comprise at least one of the following: calcium hydroxide and calcium oxide.

[0027] In the embodiment of the present application, the sodium in the red mud in the Bayer process red mud slurry is mainly present in the form of the chemical formula Na2O·Al2O3·2Si2O. Na2O·Al2O3·2Si2O reacts with a dealkalizing agent containing calcium hydroxide and / or calcium oxide to achieve Ca 2+ The Na in the Bayer red mud pulp + The alkali-free reaction product is replaced to generate CaO·3Al2O3·xSi2O and sodium hydroxide; the catalytic promoter with viscosity-reducing effect can reduce the viscosity of the dealkalization reaction solution system and regulate the contact area of ​​the reactants, thereby increasing the dealkalization rate (generating sodium hydroxide) and reducing the dealkalization reaction time, thereby reducing energy consumption; the dealkalization seed can play a role in guiding the crystal lattice of the reaction product, thereby accelerating the dealkalization reaction and improving the dealkalization efficiency. In summary, under the synergistic effect of the catalytic promoter with viscosity-reducing effect, the dealkalization promoter containing calcium hydroxide and / or calcium oxide, and the dealkalization seed, the purpose of improving the dealkalization efficiency of the Bayer process red mud slurry is achieved.

[0028] In some embodiments, the catalyst promoter includes at least one of the following: chloride salt and sulfate salt.

[0029] In some embodiments, the chloride salt comprises at least one of the following: calcium chloride, ferric chloride, sodium chloride.

[0030] In some embodiments, the sulfate salt comprises at least one of the following: iron sulfate, calcium sulfate, sodium sulfate.

[0031] In the embodiment of the present application, the catalyst aid can be a combination of one or more of chlorides and sulfates. Chlorides and sulfates have the function of electrolytes, which can make the surface charges of red mud repel each other and reduce the surface charge of red mud, thereby reducing the viscosity of the red mud in a colloidal state, and achieving the low viscosity of the Bayer process red mud slurry. Therefore, the catalyst aid reduces the viscosity of the Bayer process red mud slurry dealkalization reaction system, regulates the contact area between the reactants, increases the reaction probability between the reaction particles, thereby achieving deep dealkalization, and at the same time reduces the dealkalization time, with the advantage of low energy consumption. The chloride salt can be a combination of one or more of calcium chloride, ferric chloride, and sodium chloride, and the sulfate can be a combination of one or more of ferric sulfate, calcium sulfate, and sodium sulfate.

[0032] In some embodiments, the weight of the catalytic promoter is 0.5% to 5% of the weight of the sodium oxide in the Bayer process red mud.

[0033] In the embodiment of the present application, the weight of the catalyst aid can be 0.5% to 5% of the weight of the sodium oxide in the Bayer process red mud, because: the viscosity of the entire Bayer process red mud slurry dealkalization reaction system can be reduced well. If the weight of the catalyst aid exceeds 5% of the weight of the sodium oxide in the Bayer process red mud, it will cause excessive impurity ions in the reaction system to a certain extent, which will affect the subsequent utilization of the red mud and cause great waste; if the weight of the catalyst aid is less than 0.5% of the weight of the sodium oxide in the Bayer process red mud, it will affect the viscosity of the dealkalization reaction system and the regulation of the contact surface to a certain extent, resulting in a prolonged reaction time of the system. Exemplarily, the weight of the catalyst aid can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. of the weight of the sodium oxide in the Bayer process red mud.

[0034] In some embodiments, the dealkalized seed crystals include at least one of the following: sodium silicate, calcium aluminate, calcium aluminosilicate, sintered red mud, and silicate cement.

[0035] In the embodiment of the present application, the dealkalization seed can play a role in guiding the crystal lattice of the reaction product, and the dealkalization seed can be a combination of one or more of sodium silicate, calcium aluminate, calcium aluminosilicate, sintered red mud, and silicate cement. The dealkalization seed can serve as a seed of the dealkalization product, induce and promote the rapid generation of the dealkalization product, achieve deep dealkalization, and shorten the dealkalization reaction time.

[0036] In some embodiments, the weight of the dealkalization seed crystals is 0.5% to 5% of the weight of the Bayer process red mud.

[0037] In the embodiment of the present application, the weight of the dealkalization seed crystals can be 0.5% to 5% of the weight of the Bayer red mud, because: the role of the dealkalization seed crystals in guiding the lattice of the reaction product can be fully realized. If the weight of the dealkalization seed crystals exceeds 5% of the weight of the Bayer red mud, it will cause the solid content of the reaction system to be too high to a certain extent, affecting the reaction time and subsequent filtration performance of the system; if the weight of the dealkalization seed crystals is less than 0.5% of the weight of the Bayer red mud, it will cause the dealkalization reaction time to be prolonged to a certain extent, increasing energy consumption. Exemplarily, the weight of the dealkalization seed crystals can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. of the weight of the Bayer red mud.

[0038] In some embodiments, the dealkalization aid includes at least one of the following: quicklime, lime milk, slaked lime, and carbide slag.

[0039] In the embodiment of the present application, the dealkalization auxiliary agent can be a combination of one or more of lime milk, slaked lime, and carbide slag. The raw material component of the dealkalization auxiliary agent can be a combination of one or more of calcium hydroxide and calcium oxide. Among them, the main component of quicklime is calcium oxide, which can react chemically with water in the Bayer process red mud slurry to generate calcium hydroxide, and provide heat for the dealkalization reaction system to promote the dealkalization reaction; the main components of lime milk, slaked lime, and carbide slag are calcium hydroxide. The sodium in the red mud in the Bayer process red mud slurry mainly exists in the form of the chemical formula Na2O·Al2O3·2Si2O. Na2O·Al2O3·2SiO2 mainly reacts with calcium hydroxide to achieve Ca 2+ The Na in the Bayer red mud pulp + The weight of the dealkalizing agent can be such that the molar ratio of [Ca] / [Na] in the Bayer red mud slurry dealkalizing reaction system is ≤3.5.

[0040] In some embodiments, the concentration of the Bayer process red mud slurry is 100 g / L to 500 g / L.

[0041] In the embodiments of the present application, the concentration of the Bayer process red mud slurry can be 100g / L to 500g / L. The reason is that: it provides a suitable solid content for the dealkalization reaction system, thereby avoiding the dealkalization reaction system having too high a solid content, which affects the reaction time and filtration performance of the system; and the dealkalization reaction system having too low a solid content, which leads to a reduction in the reaction efficiency of the dealkalization system and an increase in cost. Exemplarily, the concentration of the Bayer red mud slurry can be 100g / L, 150g / L, 200g / L, 250g / L, 300g / L, 350g / L, 400g / L, 450g / L, 500g / L, etc. Further, the concentration of the Bayer red mud slurry can be 200g / L to 400g / L. Exemplarily, the concentration of the Bayer red mud slurry can be 200g / L, 230g / L, 250g / L, 270g / L, 300g / L, 320g / L, 350g / L, 330g / L, 400g / L, etc. The preparation method of the Bayer red mud slurry includes: adding hot water or red mud filtrate to the red mud slurry to form a slurry of a certain concentration.

[0042] In some embodiments, the process parameters of dealkalization include: dealkalization temperature of 60°C to 70°C, and dealkalization time of 0.1h to 0.5h.

[0043] In the embodiment of the present application, in the above-mentioned dealkalization reaction, the dealkalization temperature can be 60°C to 70°C, and the dealkalization time can be 0.1h to 0.5h. Under the action of the Bayer process red mud slurry dealkalization reaction system, the mild dealkalization temperature and the short dealkalization time are matched, and a high dealkalization rate (reaching more than 75%) can be achieved, and low cost and low energy consumption dealkalization are achieved. Therefore, under the synergistic effect of the catalyst promoter with viscosity reduction effect, the dealkalization promoter containing calcium hydroxide and or calcium oxide, and the dealkalization seed, and the mild dealkalization temperature and the short dealkalization time are matched, the purpose of improving the dealkalization rate of the Bayer process red mud slurry is achieved. Exemplarily, the dealkalization temperature can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, etc., and the dealkalization time can be 0.1h, 0.2h, 0.3h, 0.4h, 0.5h, etc. In addition, after the above step S1 is completed, the dealkalized red mud slurry is filtered, the filter cake is the dealkalized red mud, and the filtrate (sodium hydroxide solution) is returned to the alumina process.

[0044] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0045] Example 1

[0046] A method for dealkalizing Bayer red mud, comprising: S11, adding dealkalizing seed crystals and an auxiliary agent to Bayer red mud slurry to dealkalize the Bayer red mud slurry to obtain dealkalized red mud slurry; wherein the auxiliary agent comprises: a catalytic auxiliary agent with viscosity reducing effect and a dealkalizing auxiliary agent;

[0047] The preparation method of Bayer red mud slurry comprises: beating 100 grams of Bayer red mud to control the concentration to 200 g / L and the sodium oxide content to 5%, thereby obtaining Bayer red mud slurry;

[0048] The dealkalization seed is sodium silicate; the catalytic aids are calcium chloride and ferric sulfate; the dealkalization aids are carbide slag and lime milk;

[0049] The amount of the dealkalization seed crystal added was 1 gram, the amount of the catalyst additive added was 0.25 gram, and in the dealkalization system: the amount of the dealkalization additive added was until the molar ratio of [Ca] / [Na] was satisfied = 2.9;

[0050] The dealkalization temperature is 60°C and the dealkalization time is 0.1h.

[0051] The dealkalized red mud slurry was filtered to obtain 114 g of dealkalized red mud, and the filtrate was returned to the alumina process.

[0052] Example 2

[0053] A method for dealkalizing Bayer red mud, comprising: S12, adding dealkalizing seed crystals and an auxiliary agent to a Bayer red mud slurry to dealkalize the Bayer red mud slurry to obtain a dealkalized red mud slurry; wherein the auxiliary agent comprises: a catalytic auxiliary agent having a viscosity reducing effect and a dealkalizing auxiliary agent;

[0054] The preparation method of Bayer red mud slurry comprises: beating 100 grams of Bayer red mud to control the concentration to 300 g / L and the sodium oxide content to 5%, thereby obtaining Bayer red mud slurry;

[0055] The dealkalization seeds are calcium aluminate and calcium aluminosilicate; the catalytic aids are sodium sulfate and ferric chloride; the dealkalization aid is carbide slag;

[0056] The amount of the dealkalization seed crystal added was 5 g, the amount of the catalyst additive added was 0.05 g, and in the dealkalization system: the amount of the dealkalization additive added was until the molar ratio of [Ca] / [Na] was satisfied = 3.1;

[0057] The dealkalization temperature is 65°C and the dealkalization time is 0.5h.

[0058] The dealkalized red mud slurry was filtered to obtain 116 g of dealkalized red mud, and the filtrate was returned to the alumina process.

[0059] Example 3

[0060] A method for dealkalizing Bayer red mud, comprising: S13, adding dealkalizing seed crystals and an auxiliary agent to Bayer red mud raw slurry to dealkalize the Bayer red mud raw slurry to obtain dealkalized red mud slurry; wherein the auxiliary agent comprises: a catalytic auxiliary agent with viscosity reducing effect and a dealkalizing auxiliary agent;

[0061] The preparation method of Bayer red mud slurry comprises: beating 100 grams of Bayer red mud to control the concentration to 400 g / L and the sodium oxide content to 5%, thereby obtaining Bayer red mud slurry;

[0062] The dealkalization seeds are sintering red mud and silicate cement; the catalytic aids are sodium chloride and calcium sulfate; the dealkalization aids are carbide slag and slaked lime;

[0063] The amount of the dealkalization seed crystal added was 3 g, the amount of the catalyst additive added was 0.15 g, and in the dealkalization system: the amount of the dealkalization additive added was until the molar ratio of [Ca] / [Na] was satisfied = 3.3;

[0064] The dealkalization temperature is 60°C and the dealkalization time is 0.3h.

[0065] The dealkalized red mud slurry was filtered to obtain 115 g of dealkalized red mud, and the filtrate was returned to the alumina process.

[0066] Example 4

[0067] A method for dealkalizing Bayer red mud, comprising: S14, adding dealkalizing seed crystals and an auxiliary agent to a Bayer red mud slurry to dealkalize the Bayer red mud slurry to obtain a dealkalized red mud slurry; wherein the auxiliary agent comprises: a catalytic auxiliary agent having a viscosity reducing effect and a dealkalizing auxiliary agent;

[0068] The preparation method of Bayer red mud slurry comprises: beating 100 grams of Bayer red mud to control the concentration to 400 g / L and the sodium oxide content to 5%, thereby obtaining Bayer red mud slurry;

[0069] The dealkalization seed is silicate cement; the catalytic aid is sodium chloride; the dealkalization aid is slaked lime;

[0070] The amount of the dealkalization seed crystal added was 4 g, the amount of the catalyst additive added was 0.1 g, and in the dealkalization system: the amount of the dealkalization additive added was until the molar ratio of [Ca] / [Na] was satisfied = 3.1;

[0071] The dealkalization temperature is 63°C and the dealkalization time is 0.3h.

[0072] The dealkalized red mud slurry was filtered to obtain 116 g of dealkalized red mud, and the filtrate was returned to the alumina process.

[0073] Comparative Example 1

[0074] Based on the disclosure of Example 1, Comparative Example 1 is different from Example 1 in that there is no catalytic aid.

[0075] Comparative Example 2

[0076] Based on the disclosure of Example 1, Comparative Example 2 is different from Example 1 in that there is no catalytic aid and dealkalization seed.

[0077] The sodium oxide content and the dealkalization rate in the dealkalized red mud obtained by the Bayer process red mud dealkalization method provided in Examples 1 to 4 and Comparative Examples 1 to 2 were tested, and the results are shown in Table 1.

[0078] Table 1 Sodium oxide content and dealkalization rate in dealkalized red mud

[0079] Serial number Sodium oxide content in dealkalized red mud % De-alkali rate% Example 1 1％ 80％ Example 2 0.7％ 86％ Example 3 0.85％ 83％ Example 4 0.86％ 82％ Comparative Example 1 1.8 64％ Comparative Example 2 2.4 52％

[0080] As can be seen from Table 1, the Bayer process red mud dealkalization method provided in the present application achieves the purpose of increasing the dealkalization rate of the Bayer process red mud slurry under the synergistic effect of the catalyst with viscosity reduction effect, the dealkalization agent containing calcium hydroxide and / or calcium oxide, and the dealkalization seed, and matches the mild dealkalization temperature and the short dealkalization time. The dealkalization rate of Examples 1 to 3 reaches more than 80%. In Comparative Example 1, in the absence of a catalyst, the viscosity of the slurry increases, and the dealkalization rate decreases significantly in the same time; and in Comparative Example 2, in the absence of a seed and a catalyst, the reaction speed slows down significantly, and the dealkalization rate decreases significantly in the same time.

[0081] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0082] (1) In the embodiment of the present application, dealkalization seed crystals are added to the Bayer process red mud slurry, which plays a role in guiding the crystal lattice of the reaction product and promotes deep dealkalization;

[0083] (2) In the embodiment of the present application, a catalytic aid is added to the Bayer process red mud slurry, which can reduce the viscosity of the dealkalization reaction solution system, regulate the contact area of ​​the reaction, and thus reduce the reaction time.

[0084] (3) The embodiment of the present application uses a de-alkali aid produced in collaboration with solid waste, thereby reducing the cost of de-alkali;

[0085] (4) The process parameters of the dealkalization in the embodiment of the present application include: the dealkalization temperature is 60° C. to 70° C., the dealkalization time is 0.1 h to 0.5 h, the dealkalization process conditions are mild, and the energy consumption is low;

[0086] (5) The Bayer process red mud dealkalization method provided in the embodiments of the present application achieves deep dealkalization, and the dealkalization rate can reach more than 75%.

[0087] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for dealkalization of Bayer red mud, characterized in that: The method comprises: Adding dealkalization seed crystals and auxiliary agents into Bayer process red mud slurry to dealkalize the Bayer process red mud slurry to obtain dealkalized red mud slurry; wherein the auxiliary agents include: a catalytic auxiliary agent with viscosity reduction effect and a dealkalization auxiliary agent, and the raw material components of the dealkalization auxiliary agent include at least one of the following: calcium hydroxide and calcium oxide.

2. The method according to claim 1, characterized in that The catalyst aid includes at least one of the following: chloride salt and sulfate salt.

3. The method according to claim 2, characterized in that The chloride salt includes at least one of the following: calcium chloride, ferric chloride, and sodium chloride.

4. The method according to claim 2, characterized in that: The sulfate includes at least one of the following: iron sulfate, calcium sulfate, and sodium sulfate.

5. The method according to any one of claims 1 to 4, characterized in that: The weight of the catalyst promoter is 0.5% to 5% of the weight of the sodium oxide in the Bayer process red mud.

6. The method according to claim 1, characterized in that The dealkalized seed crystals include at least one of the following: sodium silicate, calcium aluminate, calcium aluminosilicate, sintered red mud, and silicate cement.

7. The method according to claim 1 or 6, characterized in that: The weight of the dealkalization seed crystals is 0.5% to 5% of the weight of the Bayer process red mud.

8. The method according to claim 1, characterized in that The dealkalization auxiliary agent includes at least one of the following: quicklime, lime milk, slaked lime, and carbide slag.

9. The method according to claim 1, characterized in that: The concentration of the Bayer process red mud slurry is 100 g / L to 500 g / L.

10. The method according to claim 1, characterized in that The process parameters of dealkalization include: dealkalization temperature of 60° C. to 70° C., and dealkalization time of 0.1 h to 0.5 h.

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