Crystallization aid for preparing Bayer stone, Bayer stone slurry and preparation method

Abstract

The invention provides a crystallization auxiliary agent for preparing Bayer stone, Bayer stone slurry and a preparation method, and belongs to the field of fine aluminum oxide. The crystallization auxiliary agent is prepared from the following chemical components: 20 to 30 parts of unsaturated sodium aliphatate, 15 to 25 parts of unsaturated fatty acid ester, 10 to 20 parts of alkyl sodium sulfonate, 5 to 10 parts of an emulsifier, 10 to 20 parts of an amine compound, 1 to 3 parts of a de-foaming agent and 20 to 30 parts of a solvent. According to the present invention, the chemical components of the crystallization auxiliary agent are reasonably designed, and the synergistic effect of the components is performed, such that the agglomeration of the aluminum hydroxide particles can be effectively improved, the loose agglomerate is formed, and the formed loose agglomerate is adopted as the induction seed crystal so as to effectively regulate the crystal nucleus size, improve the crystal morphology and improve the product purity in the early stage of the carbon decomposition.

Description

Technical Field

[0001] The present application relates to the technical field of fine alumina, and in particular to a crystallization aid for preparing Bayerite, Bayerite slurry and a preparation method. Background Art

[0002] Bayerite, also known as β-aluminum hydroxide, belongs to the monoclinic crystal system and has a special structure. It is often used as a catalyst or catalyst carrier. Its product morphology directly determines the size of its specific surface area. The larger the specific surface area, the larger the specific surface area of ​​the prepared catalyst and the better the catalytic effect. Therefore, morphology control is one of the main control indicators in Bayerite production.

[0003] At present, the carbonation decomposition of sodium aluminate is the main industrial production method of Bayerite. In order to adjust the morphology of aluminum hydroxide, it is usually necessary to add fine-grained β-aluminum hydroxide as a seed. However, existing preparation methods, such as grinding coarse-grained β-aluminum hydroxide or using sodium bicarbonate to prepare seeds, have certain problems. The grinding method will increase production costs and energy consumption, while the sodium bicarbonate preparation method has a long process and produces a by-product of sodium carbonate, which brings inconvenience to production and limits the application of β-aluminum hydroxide seeds in Bayerite production. At the same time, the existing crystallization aids are mainly used to increase the particle size and strength of aluminum hydroxide, and the prepared aluminum hydroxides are all dense agglomerates, and their mechanism of action is mainly to enhance the bonding effect between aluminum hydroxides. In order to improve the catalytic effect, the catalyst industry requires a larger specific surface area and requires the precursor to be a loose agglomerate. Therefore, it is necessary to adjust the composition of the crystallization aid in combination with the decomposition process to change its effect. Summary of the invention

[0004] The present application provides a crystallization aid for preparing Bayerite, Bayerite slurry and preparation method to solve the following technical problem: how to effectively improve the agglomeration of aluminum hydroxide particles and form loose agglomerates at the same time.

[0005] In the first aspect, the present application provides a crystallization aid for preparing Bayerite, which is composed of the following chemical components, in parts by weight: 20 to 30 parts of unsaturated fatty acid sodium, 15 to 25 parts of unsaturated fatty acid ester, 10 to 20 parts of alkyl sodium sulfonate, 5 to 10 parts of emulsifier, 10 to 20 parts of amine compounds, 1 to 3 parts of defoaming agent and 20 to 30 parts of solvent.

[0006] Optionally, the unsaturated fatty acid sodium has 12 to 18 carbon atoms.

[0007] Optionally, the unsaturated fatty acid ester includes one or more of polyethylene glycol dioleate, methyl oleate and methyl linoleate.

[0008] Optionally, the sodium alkyl sulfonate includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl secondary alkyl sulfonate, sodium α-olefin sulfonate and fatty alcohol polyoxyethylene ether sulfonate.

[0009] Optionally, the amine compound includes one or more of diethanolamine, triethanolamine and polyacrylamide.

[0010] Optionally, the emulsifier is one or more of the Span series surfactants;

[0011] The defoamer is a polyether siloxane defoamer.

[0012] In a second aspect, the present application provides a method for preparing the crystallization aid according to any one embodiment of the first aspect, the method comprising:

[0013] Dissolving unsaturated fatty acid sodium in a solvent with a set temperature to obtain a mixed solution;

[0014] Unsaturated fatty acid ester, sodium alkyl sulfonate, amine compound, emulsifier and defoamer are added to the mixed solution in sequence to obtain the crystallization aid.

[0015] Optionally, the set temperature is 35°C to 60°C.

[0016] In a third aspect, the present application provides a Bayerite slurry, wherein the Bayerite slurry is prepared by the crystallization aid described in any one of the embodiments in the first aspect.

[0017] In a fourth aspect, the present application provides a method for preparing a Bayerite slurry as described in the embodiment of the third aspect, the method comprising:

[0018] Adding the crystallization aid to a sodium aluminate solution having a set αk and a set AO concentration to obtain a mixed solution;

[0019] A mixed gas having a set CO2 volume concentration is introduced into the mixed liquid to perform a carbonation reaction under set conditions, and the N K Reaching the setting N K concentration to obtain Bayer stone slurry.

[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0021] The present application provides a crystallization aid for preparing Bayerite, which is composed of the following chemical components by weight: 20 to 30 parts of sodium unsaturated fatty acid, 15 to 25 parts of unsaturated fatty acid ester, 10 to 20 parts of sodium alkyl sulfonate, 5 to 10 parts of emulsifier, 10 to 20 parts of amine compound, 1 to 3 parts of defoamer and 20 to 30 parts of solvent. The present application rationally designs the chemical components of the crystallization aid to give play to the synergistic effect of the components. On the one hand, components such as sodium unsaturated fatty acid, sodium alkyl sulfonate and emulsifier uniformly disperse aluminum hydroxide particles in an aqueous solution and maintain their stability by reducing surface tension and dispersing. At the same time, components such as unsaturated fatty acid ester and amine compound tightly bond the dispersed aluminum hydroxide particles together through bonding to form agglomerates. On the other hand, components such as unsaturated fatty acid esters, emulsifiers and amine compounds affect the growth mode and rate of aluminum hydroxide crystals, and interact with the functional groups on the surface of aluminum hydroxide particles through the functional groups in their molecular structures, thereby regulating the internal structure of the agglomerates to form loose agglomerates. This can effectively improve the agglomeration of aluminum hydroxide particles and form loose agglomerates. The loose agglomerates are formed as induced crystal seeds, so that the size of the crystal nucleus can be effectively regulated, the crystal morphology can be improved, and the purity of the product can be improved in the early stage of carbon decomposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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.

[0023] 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.

[0024] Figure 1 A schematic flow chart of a method for preparing a crystallization aid provided in an embodiment of the present application;

[0025] Figure 2 The SEM image of Bayerite provided in Example 1 of the present application;

[0026] Figure 3 The SEM image of Bayerite provided in Example 2 of the present application;

[0027] Figure 4 The SEM image of Bayerite provided in Example 3 of the present application;

[0028] Figure 5 The SEM image of Bayerite provided in Example 4 of the present application;

[0029] Figure 6 The SEM image of Bayerite provided in Example 5 of the present application;

[0030] Figure 7 The SEM image of Bayerite provided in Example 6 of the present application;

[0031] Figure 8 The SEM image of Bayerite provided in Example 7 of the present application;

[0032] Fig. 9 This is the SEM image of Bayerite provided for Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0033] 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.

[0034] 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.

[0035] In addition, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B 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" means one or more, and "plurality" means two or more. "At least one", "the following at least one item (items)" or similar expressions refer to any combination of these items, including any combination of single items (items) or plural items (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. "Parts" such as parts by weight and parts by mass indicate the proportional relationship between the components. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, the mass ratio of substance A, substance B, and substance C is 1:2:3, then substance A, substance B, and substance C should correspond one-to-one with the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0036] 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.

[0037] The present application provides a crystallization aid for preparing Bayerite, which is composed of the following chemical components in parts by weight: 20 to 30 parts of unsaturated fatty acid sodium, 15 to 25 parts of unsaturated fatty acid ester, 10 to 20 parts of alkyl sodium sulfonate, 5 to 10 parts of emulsifier, 10 to 20 parts of amine compound, 1 to 3 parts of defoaming agent and 20 to 30 parts of solvent.

[0038] The crystallization aid exerts the synergistic effect of various agents by adding chemical components that reduce the surface tension of particles and have appropriate bonding properties. In the early stage of carbon decomposition, it can quickly bond the formed fine particles together to form loose agglomerates. These agglomerates act as induced crystal seeds to quickly control the size of the crystal nucleus, improve the crystal size and morphology, and thus improve the purity of the product. This can not only improve the agglomeration effect of aluminum hydroxide particles, but also form a Bayerite product with a large specific surface area.

[0039] The various components of the crystallization aid play different roles, as follows:

[0040] Sodium unsaturated fatty acids: Sodium unsaturated fatty acids have the property of reducing the surface tension of particles, which helps the adhesion between fine particles. By reducing the surface tension, it can enhance the interaction between particles, making it easier to form agglomerates. At the same time, sodium unsaturated fatty acids may also play an emulsifying or dispersing role, further promoting the uniform distribution and adhesion of particles.

[0041] Unsaturated fatty acid esters: As part of the crystallization aid, unsaturated fatty acid esters interact with other components through the unsaturated bonds in their molecular structure, thereby enhancing the bonding force between particles. This bonding effect helps to tightly bond fine particles together to form stable agglomerates. At the same time, unsaturated fatty acid esters may also have a certain impact on the growth mode of aluminum hydroxide crystals, and by regulating the growth process of the crystals, it helps to form agglomerates with a loose structure.

[0042] Sodium alkyl sulfonate: As an anionic surfactant, sodium alkyl sulfonate can significantly reduce surface tension and promote the dispersion and mixing of particles. This helps fine particles to be more evenly distributed in the reaction system, thereby improving the efficiency of agglomerate formation. At the same time, sodium alkyl sulfonate can also improve the stability of the system and prevent particles from agglomerating or precipitating during the reaction. This helps maintain the stability of the reaction system and ensures that aluminum hydroxide particles can be formed and agglomerated smoothly.

[0043] Emulsifier: Emulsifier can reduce the interfacial tension between two immiscible liquids, thereby promoting their mixing and dispersion. In this system, emulsifier helps to evenly disperse components such as unsaturated fatty acid sodium and unsaturated fatty acid esters in the solvent, allowing them to function more effectively. At the same time, emulsifiers may also make the adhesion between fine particles more compact and uniform through their emulsification effect. This helps to form more stable agglomerates and improve the quality and performance of the product.

[0044] Amine compounds: Amine compounds have the function of adjusting the pH value of the system. By adjusting the pH value, the charge state and interaction force of aluminum hydroxide particles can be affected, thereby regulating the formation process and structure of agglomerates. At the same time, the amino or imino groups of amine compounds can form hydrogen bonds or coordination bonds with the hydroxyl groups on the surface of aluminum hydroxide particles, thereby enhancing the adhesion between particles. This effect of enhancing adhesion helps to form more stable agglomerates.

[0045] Defoamer: Defoamer can eliminate the foam generated during the reaction. The presence of foam may interfere with the dispersion and bonding process of particles and reduce the efficiency and quality of agglomerate formation. By adding defoamer, the stability of the reaction system can be maintained to ensure that aluminum hydroxide particles can be formed and agglomerated smoothly.

[0046] Sodium unsaturated fatty acids, unsaturated fatty acid esters, sodium alkyl sulfonates and amine compounds are the main ingredients of crystallization aids and play a major role. At the same time, other ingredients are also indispensable. Each component has a synergistic and synergistic effect. Only after several components are compounded can the optimal performance be achieved. If any component is removed or replaced, the performance of the product will be significantly reduced.

[0047] On the one hand, components such as unsaturated fatty acid sodium, alkyl sodium sulfonate and emulsifier disperse aluminum hydroxide particles uniformly in aqueous solution and maintain their stability by reducing surface tension and dispersing. Components such as unsaturated fatty acid esters and amine compounds bind the dispersed aluminum hydroxide particles tightly together to form agglomerates through bonding.

[0048] On the other hand, the unsaturated double bonds in the unsaturated fatty acid ester molecules can be inserted into the growth interface of aluminum hydroxide crystals, affecting the growth direction and rate of the crystals through the steric effect. This regulatory effect helps to form crystals with porous or loose structures, thereby forming loose agglomerates. Emulsifier molecules can also be adsorbed on the growth interface of aluminum hydroxide crystals, and through the balance of their hydrophilic and hydrophobic groups, they regulate the growth process of the crystals and further promote the formation of loose structures. The amino or imino groups in the amine compound molecules can form hydrogen bonds or coordination bonds with the hydroxyl groups on the surface of aluminum hydroxide particles. These interactions not only enhance the adhesion between the particles, but also may form a certain spatial structure between the particles, so that there are gaps and channels inside the agglomerates, forming a loose structure. Components such as unsaturated fatty acid sodium and sodium alkyl sulfonate can also affect the arrangement and stacking mode of aluminum hydroxide particles through intermolecular interactions, such as electrostatic interactions and van der Waals forces, thereby regulating the looseness of the agglomerates.

[0049] In summary, the various components in the crystallization aid jointly promote the agglomeration of aluminum hydroxide particles and the formation of loose agglomerates through synergistic mechanisms such as reducing surface tension, dispersion, bonding, crystal growth regulation, intermolecular interaction, and solvent effect. These mechanisms are interrelated and interdependent, and together constitute a complex system, which makes the crystallization aid have a significant effect in alumina production. By optimizing the ratio of each component and process conditions, the agglomeration efficiency of aluminum hydroxide particles and the quality of loose agglomerates can be further improved, providing strong support for the optimization and upgrading of alumina production. Exemplarily, the weight parts of unsaturated fatty acid sodium can be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, etc., the weight parts of unsaturated fatty acid ester can be 15 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 25 parts, etc., the weight parts of alkyl sodium sulfonate can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc., the weight parts of emulsifier can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc., the weight parts of amine compounds can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc., the weight parts of defoaming agent can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc., and the weight parts of solvent can be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, etc.

[0050] In some embodiments, the unsaturated fatty acid sodium has 12 to 18 carbon atoms.

[0051] The number of carbon atoms of sodium unsaturated fatty acids is between 12 and 18, and they belong to long-chain fatty acid salts, have good surface activity and emulsification properties, and are conducive to the adhesion between fine particles. Exemplarily, the number of carbon atoms of sodium unsaturated fatty acids can be 12, 13, 14, 15, 16, 17, 18, etc.

[0052] In some embodiments, the sodium unsaturated fatty acid includes one or more of sodium dodecenoate (C12:1), sodium tetradecenoate (C14:1, sodium myristoleate), sodium hexadecenoate (C16:1, sodium palmitoleate), sodium octadecenoate (C18:1, sodium oleate) and sodium octadecadienoate (C18:2, sodium linoleate).

[0053] In some embodiments, the unsaturated fatty acid ester includes one or more of polyethylene glycol dioleate, methyl oleate and methyl linoleate.

[0054] In some embodiments, the sodium alkyl sulfonate includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl secondary alkyl sulfonate, sodium α-olefin sulfonate and fatty alcohol polyoxyethylene ether sulfonate.

[0055] In some embodiments, the amine compound includes: one or more of diethanolamine, triethanolamine and polyacrylamide.

[0056] In some embodiments, the emulsifier is one or more of the Span series surfactants; and / or,

[0057] The defoamer is a polyether siloxane defoamer.

[0058] In some embodiments, the Span series surfactants include: Span 20 (monolaurate), Span 40 (monopalmitate), Span 60 (monostearate), Span 80 (monooleate), and Span 85.

[0059] The basic chemical composition of the Span series products is sorbitan fatty acid esters, which are soluble in hot ethanol, toluene and other organic solvents, insoluble in water, but dispersible in hot water. The HLB value ranges from 4.3 to 8.6, which varies with the combined fatty acids. The Span series surfactants have good thermal stability and hydrolysis stability.

[0060] In some embodiments, the polyether siloxane defoamer includes: one or more of a polyether-modified silicone oil defoamer, a polyether siloxane copolymer defoamer, a polyether ester siloxane defoamer, and a self-emulsifying polyether siloxane defoamer.

[0061] It is understandable that polyether siloxane defoamers are copolymers that introduce polyether segments onto siloxane segments. Polyether is grafted onto polysiloxane chains through condensation technology, thereby combining the advantages of both polysiloxane and polyether defoamers. In the molecules of siloxane copolymers, the siloxane segment is a lipophilic group and the polyether segment is a hydrophilic group. This structure enables polyether siloxane defoamers to self-emulsify in polar solution systems and have a lasting defoaming effect.

[0062] In some embodiments, the solvent is demineralized water.

[0063] Figure 1 A schematic flow chart of a method for preparing a crystallization aid provided in an embodiment of the present application.

[0064] Based on a general inventive concept, see Figure 1 The present application provides a method for preparing the crystallization aid described in any one of the above embodiments, the method comprising:

[0065] S11, dissolving unsaturated fatty acid sodium in a solvent with a set temperature to obtain a mixed solution;

[0066] S12, adding unsaturated fatty acid ester, sodium alkyl sulfonate, amine compound, emulsifier and defoamer to the mixed solution in sequence to obtain the crystallization aid.

[0067] In some embodiments, the set temperature is 35°C to 60°C.

[0068] The addition temperature of the sodium unsaturated fatty acid is limited to 35°C to 60°C, which helps to fully dissolve the sodium unsaturated fatty acid while avoiding unnecessary reactions or degradation of the sodium unsaturated fatty acid. Exemplarily, the addition temperature of the sodium unsaturated fatty acid is 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, etc.

[0069] The product prepared by the method for preparing the crystallization aid is the above-mentioned crystallization aid. The chemical composition of the crystallization aid prepared by the method for preparing the crystallization aid can refer to the above-mentioned embodiment. Since the method for preparing the crystallization aid adopts part or all of the technical solutions of the crystallization aid embodiment, it at least has all the beneficial effects brought by the technical solutions of the crystallization aid embodiment, which will not be described one by one here.

[0070] Based on a general inventive concept, the present application also provides a Bayerite slurry, wherein the Bayerite slurry is prepared by the crystallization aid described in any one of the above embodiments.

[0071] Based on a general inventive concept, the present application provides a method for preparing a Bayerite slurry as described in the above embodiment, the method comprising:

[0072] S21, adding the crystallization aid to a sodium aluminate solution having a set αk and a set AO concentration to obtain a mixed solution;

[0073] S22, introducing a mixed gas having a set CO2 volume concentration into the mixed liquid to perform a carbonation reaction under set conditions, and wait until the N K Reaching the setting N K concentration to obtain Bayer stone slurry;

[0074] S23, performing solid-liquid separation on the Bayerite slurry to obtain Bayerite.

[0075] In some embodiments, the mass of the crystallization aid is 0.1% to 3% of the mass of the sodium aluminate solution.

[0076] The present application rationally designs the chemical composition of the crystallization aid, realizes the synergistic effect between the agents, forms loose agglomerates as inducing crystal seeds, thereby effectively regulating the size of the crystal nucleus, improving the crystal morphology, and improving the product purity in the early stage of carbon decomposition. Exemplarily, the mass of the crystallization aid is 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, etc. of the mass of the sodium aluminate solution.

[0077] In some embodiments, the sodium aluminate solution is mainly derived from a sintering process semen system, the concentration of AO is 90-120 g / L, and the molar ratio of caustic soda to alumina is 1.4-1.6.

[0078] In some embodiments, the temperature of the carbonation reaction is 30° C. to 60° C., and the time of the carbonation reaction is 15 min to 45 min.

[0079] In some embodiments, the NK concentration is set to 8 g / L to 15 g / L.

[0080] 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 industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.

[0081] Example 1

[0082] This embodiment provides a crystallization aid for preparing Bayerite, which is composed of the following chemical components in parts by weight: 20 parts of unsaturated fatty acid sodium, 20 parts of unsaturated fatty acid ester, 15 parts of alkyl sodium sulfonate, 5 parts of emulsifier, 15 parts of amine compound, 1 part of defoamer and 24 parts of solvent;

[0083] Wherein, the unsaturated fatty acid sodium is sodium linoleate;

[0084] The unsaturated fatty acid ester is polyethylene glycol dioleate;

[0085] The sodium alkyl sulfonate is sodium dodecyl sulfonate;

[0086] The emulsifier is Span 80;

[0087] The amine compound is triethanolamine;

[0088] The defoamer is a polyether siloxane defoamer;

[0089] The solvent is soft water.

[0090] Based on the crystallization aid, this embodiment also provides a preparation method of the crystallization aid for preparing Bayerite, which may specifically include the following steps:

[0091] Heat the required solvent to 45°C, then add unsaturated fatty acid sodium according to the ratio, stir until it is completely dissolved, then add unsaturated fatty acid ester, sodium alkyl sulfonate, amine compound, emulsifier, defoamer in sequence, and continue stirring until the materials are completely dissolved to obtain the crystallization aid.

[0092] Based on the crystallization aid, this embodiment also provides an application of the crystallization aid for preparing Bayerite, which may specifically include the following steps:

[0093] Take alumina sintering method semen, αk 1.5, AO 105g / L, dilute with water to AO concentration 53g / L, cool to 40℃, take an appropriate amount and pour into a beaker with a carbon separation device, start stirring, stirring speed 300r / min, add crystallization aid, the added mass of crystallization aid is 1% of the mass of alumina sintering method semen, stir for 5min, then pass 37% CO2 for carbon decomposition, end point N K The concentration is controlled at 7g / L to obtain Bayerite slurry, which is filtered to obtain filter cake, which is then washed and dried to obtain Bayerite.

[0094] Example 2

[0095] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0096] The crystallization aid is composed of the following chemical components: 25 parts of unsaturated fatty acid sodium, 20 parts of unsaturated fatty acid ester, 10 parts of alkyl sodium sulfonate, 5 parts of emulsifier, 15 parts of amine compound, 1 part of defoamer and 24 parts of solvent.

[0097] Example 3

[0098] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0099] The crystallization aid is composed of the following chemical components: 30 parts of unsaturated fatty acid sodium, 20 parts of unsaturated fatty acid ester, 10 parts of alkyl sodium sulfonate, 5 parts of emulsifier, 10 parts of amine compound, 1 part of defoamer and 24 parts of solvent.

[0100] Example 4

[0101] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0102] The crystallization aid is composed of the following chemical components: 20 parts of unsaturated fatty acid sodium, 15 parts of unsaturated fatty acid ester, 20 parts of alkyl sodium sulfonate, 5 parts of emulsifier, 15 parts of amine compound, 1 part of defoamer and 24 parts of solvent;

[0103] Wherein, the unsaturated fatty acid sodium is sodium laurate;

[0104] The unsaturated fatty acid ester is polyethylene glycol dioleate;

[0105] The sodium alkyl sulfonate is sodium hexadecyl sulfonate;

[0106] The emulsifier is Span 60;

[0107] The amine compound is polyacrylamide;

[0108] The defoamer is a polyether siloxane defoamer;

[0109] The solvent is soft water.

[0110] Example 5

[0111] This embodiment is further modified as follows based on the content disclosed in Embodiment 4:

[0112] The crystallization aid is composed of the following chemical components: 20 parts of unsaturated fatty acid sodium, 25 parts of unsaturated fatty acid ester, 10 parts of alkyl sodium sulfonate, 5 parts of emulsifier, 15 parts of amine compound, 1 part of defoamer and 24 parts of solvent.

[0113] Example 6

[0114] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0115] The crystallization aid is composed of the following chemical components: 20 parts of unsaturated fatty acid sodium, 17 parts of unsaturated fatty acid ester, 12 parts of alkyl sodium sulfonate, 7 parts of emulsifier, 11 parts of amine compound, 3 parts of defoamer and 30 parts of solvent;

[0116] Wherein, the unsaturated fatty acid sodium is sodium linoleate;

[0117] The unsaturated fatty acid ester is polyethylene glycol dioleate;

[0118] The sodium alkyl sulfonate is sodium secondary alkyl sulfonate;

[0119] The emulsifiers are Span 20 and Span 80;

[0120] The amine compound is triethanolamine;

[0121] The defoamer is a polyether siloxane defoamer;

[0122] The solvent is soft water.

[0123] In the process of preparing Bayerite, the mass of crystallization aid added is 3% of the mass of alumina sintering concentrate.

[0124] Example 7

[0125] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0126] The crystallization aid is composed of the following chemical components: 20 parts of unsaturated fatty acid sodium, 17 parts of unsaturated fatty acid ester, 12 parts of alkyl sodium sulfonate, 7 parts of emulsifier, 11 parts of amine compound, 3 parts of defoamer and 30 parts of solvent;

[0127] Wherein, the unsaturated fatty acid sodium is palm oil fatty acid sodium;

[0128] The unsaturated fatty acid ester is methyl linoleate;

[0129] The sodium alkyl sulfonate is sodium secondary alkyl sulfonate;

[0130] The emulsifier is Span 80;

[0131] The amine compound is diethanolamine;

[0132] The defoamer is a polyether siloxane defoamer;

[0133] The solvent is soft water.

[0134] In the process of preparing Bayerite, the mass of crystallization aid added is 5% of the mass of alumina sintering concentrate.

[0135] Comparative Example 1

[0136] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0137] In the process of preparing Bayerite, no crystallization aids are added.

[0138] Comparative Example 2

[0139] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0140] No unsaturated fatty acid sodium is added to the crystallization aid.

[0141] Comparative Example 3

[0142] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0143] No unsaturated fatty acid ester is added to the crystallization aid.

[0144] Comparative Example 4

[0145] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0146] No sodium alkyl sulfonate was added as the crystallization aid.

[0147] Comparative Example 5

[0148] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0149] No emulsifier was added to the crystallization aid.

[0150] Comparative Example 6

[0151] This embodiment is further modified as follows based on the content disclosed in Embodiment 1:

[0152] No amine compounds are added to the crystallization aid.

[0153] The performance of the Bayer stones obtained in Examples 1 to 7 and Comparative Examples 1 to 6 was measured, and the results are shown in Table 1.

[0154] Table 1 Bayerite index results obtained in the examples and comparative examples

[0155]

[0156]

[0157] As shown in Table 1, the Bayer stones obtained in Examples 1 to 7 have a particle size D50 of 15 μm to 25 μm, a purity of ≥ 97.5%, and a packing density of ≤ 0.75 g / cm 3 In comparative examples 1 to 6, the packing density of Bayerite is higher than that of the embodiment, indicating that the various components in the crystallization aid jointly promote the agglomeration of aluminum hydroxide particles and the formation of loose agglomerates through a synergistic mechanism. If any one of them is reduced, the loose packing density will increase to varying degrees, which is not conducive to the preparation of Bayerite in the catalyst industry.

[0158] Figure 2 The SEM image of Bayerite provided in Example 1 of the present application; Figure 3 The SEM image of Bayerite provided in Example 2 of the present application; Figure 4 The SEM image of Bayerite provided in Example 3 of the present application; Figure 5 The SEM image of Bayerite provided in Example 4 of the present application; Figure 6 The SEM image of Bayerite provided in Example 5 of the present application; Figure 7 The SEM image of Bayerite provided in Example 6 of the present application; Figure 8 The SEM image of Bayerite provided in Example 7 of the present application; Fig. 9 The SEM image of Bayerite provided for Comparative Example 1 of this application. Figures 2 to 9 It can be seen that after adding the crystallization aid, the morphology of the product obviously changes from a dense state to a loose state, and the loose density is significantly reduced, which meets the needs of the catalytic industry.

[0159] In addition, one or more technical solutions in the embodiments of the present application have at least the following technical effects or advantages:

[0160] In the examples of the present application, the obtained new crystallization aid overcomes the problems of poor applicability of existing crystallization aids, long Bayerite production process, high cost and other technical defects. In the carbonation decomposition process of sodium aluminate, by adding the new agent, not only the applicability of the aid is improved, but also a Bayerite product suitable for use in the catalytic industry is prepared, which greatly shortens the process and reduces costs, providing a new idea for improving the economic benefits of sintered alumina production.

[0161] In the embodiments of the present application, the crystallization aid is different from the commercially available oily crystallization aid, and has the characteristics of small foam, low cost, good effect, etc.

[0162] In the embodiments of the present application, a crystallization aid is added which has the functions of reducing the surface tension of the particles and achieving proper bonding, so as to exert the synergistic effect of the agents, quickly bond the fine particles formed in the initial stage of carbon decomposition together, form induced crystal seeds, and control the morphology of the product.

[0163] In the examples of the present application, the crystallization aid is directly added to the sodium aluminate solution during the implementation process, without adding new equipment or processes, and the operation is simple and easy to industrialize.

[0164] 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 crystallization aid for preparing Bayerite, wherein the crystallization aid is composed of the following chemical components in parts by weight: 20 to 30 parts of unsaturated fatty acid sodium, 15 to 25 parts of unsaturated fatty acid ester, 10 to 20 parts of alkyl sodium sulfonate, 5 to 10 parts of emulsifier, 10 to 20 parts of amine compound, 1 to 3 parts of defoaming agent and 20 to 30 parts of solvent.

2. The crystallization aid according to claim 1, characterized in that The number of carbon atoms of the unsaturated fatty acid sodium is 12 to 18.

3. The crystallization aid according to claim 1, characterized in that The unsaturated fatty acid ester includes one or more of polyethylene glycol dioleate, methyl oleate and methyl linoleate.

4. The crystallization aid according to claim 1, characterized in that The sodium alkyl sulfonate includes one or more of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium hexadecyl sulfonate, sodium hexadecyl secondary alkyl sulfonate, sodium α-olefin sulfonate and fatty alcohol polyoxyethylene ether sulfonate.

5. The crystallization aid according to claim 1, characterized in that The amine compound includes one or more of diethanolamine, triethanolamine and polyacrylamide.

6. The crystallization aid according to claim 1, characterized in that The emulsifier is one or more of the Span series surfactants; The defoamer is a polyether siloxane defoamer.

7. A method for preparing the crystallization aid according to any one of claims 1 to 6, the method comprising: Dissolving unsaturated fatty acid sodium in a solvent with a set temperature to obtain a mixed solution; Unsaturated fatty acid ester, sodium alkyl sulfonate, amine compound, emulsifier and defoamer are added to the mixed solution in sequence to obtain the crystallization aid.

8. The method according to claim 7, characterized in that The set temperature is 35°C to 60°C.

9. A Bayerite slurry, wherein the Bayerite slurry is prepared from the crystallization aid according to any one of claims 1 to 6.

10. A method for preparing a Bayerite slurry according to claim 9, the method comprising: Adding the crystallization aid to a sodium aluminate solution having a set αk and a set AO concentration to obtain a mixed solution; A mixed gas having a set CO2 volume concentration is introduced into the mixed liquid to perform a carbonation reaction under set conditions, and the N K Reaching the setting N K concentration to obtain Bayer stone slurry.

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