Method for synergistically preparing calcium fluoride and molecular sieve based on multi-element industrial waste

Abstract

The invention provides a method for synergistically preparing calcium fluoride and a molecular sieve based on multi-element industrial waste, and belongs to the technical field of industrial waste recycling. The method comprises the following steps: respectively taking an electrolytic aluminum industry byproduct fluorine-containing waste electrolyte cryolite and lithium slag after lithium extraction of lithium ore as raw materials, performing acid leaching on the electrolyte cryolite, adding a calcium compound, separating to obtain calcium fluoride solid and a mixed solution containing aluminum chloride and sodium chloride, and adding an alkaline solution into the mixed solution to obtain an aluminum hydroxide product. And carrying out alkaline leaching on the lithium slag to obtain a mixed solution containing sodium silicate and sodium metaaluminate, and proportionally synthesizing the mixed solution with the obtained aluminum hydroxide and sodium hydroxide solution to obtain the 4A zeolite molecular sieve product. The calcium fluoride and the zeolite molecular sieve are cooperatively prepared by adopting multi-element industrial waste, and the problems that electrolyte cryolite cannot be completely applied to the aluminum electrolysis process, the lithium slag treatment cost is high and the like in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of industrial waste recycling, and in particular to a method for synergistically preparing calcium fluoride and molecular sieves based on multiple industrial wastes. Background Art

[0002] At present, the accumulated stockpile of bulk solid waste is about 60 billion tons, and the annual new stockpile is nearly 3 billion tons. The new energy vehicle industry is developing rapidly, among which lithium is a key material to support and ensure the sustainable development of the new energy vehicle industry. Lithium salt products mainly come from lithium ore extraction. However, lithium ore extraction will produce a large amount of lithium smelting slag (usually 8 to 10 tons of lithium slag will be produced for every ton of lithium salt produced). At present, the recycling and treatment of lithium slag is mainly landfill or open-air stacking.

[0003] The modern electrolytic aluminum industry is a process in which elemental aluminum is obtained through electrolysis using alumina as solute, cryolite (Na3AlF6) as flux, carbonite as anode, and aluminum liquid as cathode. The amount of fluorine-containing solid waste and waste liquid discharged is increasing day by day. Accumulation, landfill and direct discharge will not only bring serious environmental problems, but also cause waste of fluorine resources. Some people consider precipitating cryolite from the leachate, which can not only recover the fluorine-aluminum components in one step, but also increase the product value. However, due to the fine particle size and high impurity content of electrolyte cryolite powder, it cannot be fully reused in the aluminum electrolysis process, and the product value is low. Summary of the invention

[0004] The purpose of the present invention is to provide a method for the synergistic preparation of calcium fluoride and molecular sieves based on multiple industrial wastes. The present invention can not only consume the electrolyte cryolite produced by aluminum electrolysis solid waste - aluminum electrolysis cell carbon slag and lithium slag after lithium extraction from lithium ore, but also utilize by-product resources to create benefits.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for synergistically preparing calcium fluoride and molecular sieve based on multiple industrial wastes, comprising the following steps:

[0007] Cryolite, water, aluminum hydroxide and hydrochloric acid are mixed for acid leaching to obtain a leachate;

[0008] The leaching solution is mixed with a calcium compound to carry out a fluorine precipitation reaction to obtain a mixed solution of sodium chloride and aluminum chloride and a calcium fluoride solid;

[0009] The sodium chloride and aluminum chloride mixed solution is mixed with an alkaline solution to perform a precipitation reaction to obtain aluminum hydroxide solid and a chloride salt solution;

[0010] The lithium slag is mixed with a sodium hydroxide solution and subjected to an alkali treatment to obtain a mixed solution of sodium silicate and sodium metaaluminate;

[0011] The aluminum hydroxide solid, sodium silicate and sodium metaaluminate mixed solution are mixed with a sodium hydroxide solution to carry out a crystallization reaction to obtain a 4A zeolite molecular sieve.

[0012] Preferably, the fluorine content in the cryolite is 48-49.99 wt %, the mass concentration of the hydrochloric acid is 36-38%, and the purity of the aluminum hydroxide is 90-98%.

[0013] Preferably, the molar ratio of the cryolite, aluminum hydroxide, hydrochloric acid and water is 1:(1.10-1.51):(5.13-9.02):(527.78-593.75); the acid leaching temperature is 80-95°C, and the time is 1-3h.

[0014] Preferably, the F in the leachate - The mass concentration is 0.84-1.35%, the calcium compound comprises one or more of calcium oxide, calcium carbonate and calcium hydroxide, and the ratio of the amount of the calcium compound to the amount of fluorine element substance in the leaching solution is 0.90-1.20:2.

[0015] Preferably, the temperature of the fluorine deposition reaction is 70-90° C. and the time is 1-3 hours.

[0016] Preferably, in the precipitation reaction step, the alkaline solution comprises sodium hydroxide solution or ammonia water, and the mass concentration of the alkaline solution is 20-32%; the aluminum element in the sodium chloride and aluminum chloride mixture reacts with OH in the alkaline solution. - The amount of substance ratio is 1:2.80~3.20.

[0017] Preferably, the precipitation reaction is carried out at a temperature of 20 to 40° C. and for a time of 1 to 3 hours.

[0018] Preferably, in terms of mass percentage, the components of the lithium slag include SiO2 45-55% and Al2O3 15-20%. In the alkali treatment step, the mass concentration of the sodium hydroxide solution is 20-32%; the temperature of the alkali treatment is 155-180°C, and the insulation time is 2-6h.

[0019] Preferably, in the mixed solution of sodium silicate and sodium aluminate, the Na2O content is 160-260 g / L, the SiO2 content is 200-350 g / L, and the Al2O3 content is 80-110 g / L.

[0020] Preferably, in the crystallization reaction step, the amounts of the sodium hydroxide solution, aluminum hydroxide solid, and the mixed solution of sodium silicate and sodium aluminate satisfy the molar ratio of Na2O, SiO2 and Al2O3 (0.95-1.35):(1.90-2.10):1, the temperature of the crystallization reaction is 75-85°C, and the time is 3-12h.

[0021] The present invention provides a method for synergistically preparing calcium fluoride and molecular sieves based on multiple industrial wastes, respectively using electrolyte cryolite, a fluorine-containing waste by-product of the electrolytic aluminum industry, and lithium slag after lithium extraction from lithium ore as raw materials, acid-leaching the electrolyte cryolite and adding a calcium compound to separate calcium fluoride solid and a mixed solution containing aluminum chloride and sodium chloride, adding an alkaline solution to the mixed solution to obtain an aluminum hydroxide product, alkali-leaching the lithium slag to obtain a mixed solution containing sodium silicate and sodium metaaluminate, and then synthesizing a 4A zeolite molecular sieve product in proportion with the obtained aluminum hydroxide and sodium hydroxide solution. The present invention uses multiple industrial wastes to synergistically prepare calcium fluoride and co-produce zeolite molecular sieves, solving the problems in the prior art that electrolyte cryolite cannot be fully applied to the aluminum electrolysis process and the lithium slag treatment cost is high.

[0022] The invention can effectively consume multiple industrial wastes, namely electrolyte cryolite produced as a by-product of the electrolytic aluminum industry and lithium slag after lithium extraction from lithium ore, thereby reducing pollution to the environment and being environmentally friendly.

[0023] The preparation method of the invention is simple to operate, and can jointly produce high value-added calcium fluoride and zeolite molecular sieve products, greatly reducing the production costs of calcium fluoride and zeolite molecular sieve, thereby creating benefits and realizing effective utilization of resources. DETAILED DESCRIPTION

[0024] In the present invention, unless otherwise specified, the raw materials or reagents used are commercially available products well known in the art.

[0025] The present invention provides a method for synergistically preparing calcium fluoride and molecular sieve based on multiple industrial wastes, comprising the following steps:

[0026] Cryolite, water, aluminum hydroxide and hydrochloric acid are mixed for acid leaching to obtain a leachate;

[0027] The leaching solution is mixed with a calcium compound to carry out a fluorine precipitation reaction to obtain a mixed solution of sodium chloride and aluminum chloride and a calcium fluoride solid;

[0028] The sodium chloride and aluminum chloride mixed solution is mixed with an alkaline solution to perform a precipitation reaction to obtain aluminum hydroxide solid and a chloride salt solution;

[0029] The lithium slag is mixed with a sodium hydroxide solution and subjected to an alkali treatment to obtain a mixed solution of sodium silicate and sodium metaaluminate;

[0030] The aluminum hydroxide solid, sodium silicate and sodium metaaluminate mixed solution are mixed with a sodium hydroxide solution to carry out a crystallization reaction to obtain a 4A zeolite molecular sieve.

[0031] The invention mixes cryolite, water, aluminum hydroxide and hydrochloric acid, performs acid leaching, and obtains a leaching solution.

[0032] The present invention preferably adds cryolite to water for magnet iron removal, and then adds aluminum hydroxide and hydrochloric acid; the present invention has no special limitation on the magnet iron removal, and can be carried out according to the process well known in the art.

[0033] In the present invention, the fluorine content in the cryolite is preferably 48-49.99 wt %, the mass concentration of the hydrochloric acid is preferably 36-38%, and the purity of the aluminum hydroxide is preferably 90-98%.

[0034] In the present invention, the molar ratio of the cryolite, aluminum hydroxide, hydrochloric acid and water is preferably 1:(1.10-1.51):(5.13-9.02):(527.78-593.75), and more preferably 1:(1.10-1.5):(5.5-9.02):(527.78-569.38).

[0035] In the present invention, the acid leaching temperature is preferably 80 to 95° C., more preferably 80 to 90° C., further preferably 85° C., and the time is preferably 1 to 3 hours, more preferably 2 hours.

[0036] During the acid leaching process, the chemical reactions involved are:

[0037] Na3AlF6+Al(OH)3+HCl→NaCl+AlCl3+HF.

[0038] In the present invention, the F in the leaching solution - The mass concentration is 0.84~1.35%.

[0039] After obtaining the leaching solution, the present invention mixes the leaching solution with a calcium compound to carry out a fluorine precipitation reaction to obtain a mixed solution of sodium chloride and aluminum chloride and a calcium fluoride solid.

[0040] In the present invention, the calcium compound preferably includes one or more of calcium oxide, calcium carbonate and calcium hydroxide, and the ratio of the calcium compound to the amount of fluorine in the leachate is preferably 0.90-1.20:2, more preferably 1-1.05:2. When the calcium compound is two or more of the above, the present invention has no special limitation on the ratio of different types of calcium compounds, and any ratio can meet the above ratio requirements.

[0041] In the present invention, the temperature of the fluorine deposition reaction is preferably 70 to 90° C., more preferably 80 to 85° C., and the time is preferably 1 to 3 hours, more preferably 1 to 2 hours.

[0042] After the reaction is completed, the product is preferably filtered to obtain a mixed solution of sodium chloride and aluminum chloride and solid calcium fluoride. 3+ The mass concentration is 0.10~0.40%.

[0043] After obtaining the sodium chloride and aluminum chloride mixed solution, the present invention mixes the sodium chloride and aluminum chloride mixed solution with an alkaline solution to perform a precipitation reaction to obtain aluminum hydroxide solid and a chloride salt solution.

[0044] In the present invention, in the precipitation reaction step, the alkaline solution preferably includes sodium hydroxide solution or ammonia water, and the mass concentration of the alkaline solution is preferably 20-32%, more preferably 32%; the aluminum element in the sodium chloride and aluminum chloride mixture reacts with OH in the alkaline solution. - The amount ratio of the substance is 1:2.8 to 3.2, and more preferably 1:3.

[0045] In the present invention, the temperature of the precipitation reaction is preferably 20-40° C., more preferably 25° C., and the time is preferably 1-3 h, more preferably 1 h.

[0046] During the precipitation reaction, the reactions involved are:

[0047] AlCl3+NaOH→Al(OH)3↓ or AlCl3+NH3·H2O→Al(OH)3↓.

[0048] The invention mixes lithium slag with sodium hydroxide solution and performs alkali treatment to obtain a mixed solution of sodium silicate and sodium metaaluminate.

[0049] In the present invention, the components of the lithium slag include SiO245-55% and Al2O315-20% in terms of mass percentage, and the mass concentration of the sodium hydroxide solution is preferably 20-32%, more preferably 21.73-26.85%; the mass ratio of the lithium slag to the sodium hydroxide solution is preferably 1:1.5-5, more preferably 1:2.14-2.39, and further preferably 1:2.22.

[0050] In the present invention, the temperature of the alkali treatment is preferably 155-180° C., more preferably 162-175° C., and the insulation time is preferably 2-6 h, more preferably 5 h.

[0051] During the alkali treatment, the reactions involved are:

[0052] SiO2+NaOH→Na2SiO3, Al2O3+NaOH+H2O→NaAlO2

[0053] After the alkali treatment is completed, the present invention preferably filters the obtained product to obtain a mixed solution of sodium silicate and sodium metaaluminate.

[0054] In the present invention, in the mixed solution of sodium silicate and sodium aluminate, the Na2O content is 160-260 g / L, the SiO2 content is 200-350 g / L, and the Al2O3 content is 80-110 g / L.

[0055] After obtaining aluminum hydroxide solid and a mixed solution of sodium silicate and sodium aluminate, the present invention mixes the aluminum hydroxide solid, the mixed solution of sodium silicate and sodium aluminate with a sodium hydroxide solution to perform a crystallization reaction to obtain a 4A zeolite molecular sieve.

[0056] In the present invention, in the step of the crystallization reaction, the amounts of the sodium hydroxide solution, aluminum hydroxide solid, and the mixed solution of sodium silicate and sodium aluminate satisfy the molar ratio of Na2O, SiO2 and Al2O3 of (0.95-1.35):(1.90-2.10):1, more preferably (1.15-1.25):(1.96-2.06):1.

[0057] In the present invention, the crystallization reaction temperature is preferably 75-85°C, more preferably 81-82°C, and the time is preferably 3-12h, more preferably 3h. During the crystallization reaction, the condensed water formed by the steam heating of the inner coil is used to wash the 4A zeolite molecular sieve.

[0058] During the crystallization reaction, the reactions involved are:

[0059] Al(OH)3↓+NaOH→NaAlO2

[0060] NaAlO2+Na2SiO3→Na2O·2SiO2·Al2O3·2H2O.

[0061] After the crystallization is completed, the present invention preferably separates, washes and dries the obtained slurry to obtain 4A zeolite molecular sieve.

[0062] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are conventional methods unless otherwise specified.

[0063] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available.

[0064] In the following examples, the fluorine content in cryolite is 48-49.99 wt %, the mass concentration of the hydrochloric acid is 36-38%, and the purity of aluminum hydroxide is 90-98%;

[0065] The composition of lithium slag includes SiO2 45-55% and Al2O3 15-20%.

[0066] Example 1

[0067] 820 g of water was added to 20 g of electrolyte cryolite (fluorine content was 48 wt%) to remove iron from the magnet, and then 9.89 g of aluminum hydroxide (purity 98%) and 43.75 g of hydrochloric acid (concentration 36 wt%) were added. The molar ratio of cryolite, aluminum hydroxide, hydrochloric acid and water was 0.08:0.12:0.43:45.55. The mixture was acid-leached at 80 ° C for 3 h to obtain a leachate (F in the leachate was 1.34 W / m). - Mass concentration is 1.07wt%);

[0068] 17.71 g of calcium oxide (purity of 80%) was added to the leachate, the ratio of calcium oxide to the amount of fluorine in the leachate was 1:2, the mixture was reacted at 80° C. for 1 h, and filtered to obtain 19.35 g of calcium fluoride solid (content of 98%) and a mixed solution of sodium chloride and aluminum chloride (Al in the mixed solution was 2.3 g). 3+ Mass concentration is 0.37wt%);

[0069] Add 46.70 g of a 32 wt % sodium hydroxide solution to the sodium chloride and aluminum chloride mixture, wherein the molar ratio of aluminum element to sodium hydroxide in the mixture is 1:3, and perform a precipitation reaction at room temperature for 1 h to obtain aluminum hydroxide solid and a sodium chloride solution;

[0070] The lithium slag (mainly comprising SiO2 55.00%, Al2O3 15.00%) and the sodium hydroxide solution with a concentration of 26.85wt% were mixed in a mass ratio of 1:2.14, and a water glass reaction drum was used for heat preservation at 162°C for 5h, and after filtering, a mixed solution of sodium silicate and sodium metaaluminate with a Na2O content of 208.02g / L, a SiO2 content of 332.31g / L, and an Al2O3 content of 90.63g / L was obtained;

[0071] The prepared aluminum hydroxide solid, sodium silicate and sodium aluminate mixture and sodium hydroxide solution were mixed in a Na2O:SiO2:Al2O3 molar ratio of 1.25:2.06:1, and crystallized at 82°C for 3 hours. The resulting slurry was separated, washed and dried to obtain 4A zeolite molecular sieve (static water adsorption of 24.3%).

[0072] Example 2

[0073] 820 g of water was added to 20 g of electrolyte cryolite (fluorine content was 48 wt%) to remove iron from the magnet, and then 8.24 g of aluminum hydroxide (purity 98%) and 43.75 g of hydrochloric acid (concentration 36 wt%) were added. The molar ratio of cryolite, aluminum hydroxide, hydrochloric acid and water was 0.08:0.1:0.43:45.55. The mixture was acid-leached at 85 ° C for 3 h to obtain a leachate (F in the leachate was 1.34 W / m). - Mass concentration is 1.08%);

[0074] 18.59 g of calcium oxide (purity of 80%) was added to the leachate, the molar ratio of calcium oxide to fluorine in the leachate was 1.05:2, the mixture was reacted at 80° C. for 1 h, and filtered to obtain 19.69 g of calcium fluoride solid (content of 98%) and a mixed solution of sodium chloride and aluminum chloride (Al in the mixed solution was 1.05:2). 3+ Mass concentration is 0.31%);

[0075] Add 38.87 g of a 32 wt % sodium hydroxide solution to the sodium chloride and aluminum chloride mixture, wherein the molar ratio of aluminum element to sodium hydroxide in the mixture is 1:3, and perform a precipitation reaction at room temperature for 1 hour to obtain aluminum hydroxide solid and a sodium chloride solution;

[0076] Lithium slag (mainly composed of SiO2 54.00%, Al2O3 16.00%) and sodium hydroxide solution with a concentration of 21.73wt% were mixed in a mass ratio of 1:2.39, and a water glass reaction drum was used for heat preservation at 175°C for 5h. After filtering, a mixed solution of sodium silicate and sodium metaaluminate with a Na2O content of 168.32g / L, a SiO2 content of 278.08g / L and an Al2O3 content of 82.39g / L was obtained;

[0077] The prepared aluminum hydroxide solid, sodium silicate and sodium aluminate mixture and sodium hydroxide solution were mixed in a Na2O:SiO2:Al2O3 molar ratio of 1.15:1.96:1, and crystallized at 82°C for 3 hours. The resulting slurry was separated, washed and dried to obtain 4A zeolite molecular sieve (static water adsorption of 24.6%).

[0078] Example 3

[0079] 850 g of water was added to 20 g of electrolyte cryolite (fluorine content was 48 wt%) to remove iron from the magnet, and then 9.89 g of aluminum hydroxide (purity 98%) and 41.62 g of hydrochloric acid (concentration 36 wt%) were added. The molar ratio of cryolite, aluminum hydroxide, hydrochloric acid and water was 0.08:0.12:0.41:47.22. The mixture was acid-leached at 90 ° C for 1 h to obtain a leachate (F in the leachate was 1.3 g). -Mass concentration is 1.04%);

[0080] 18.59 g of calcium oxide (purity of 80%) was added to the leachate, the molar ratio of calcium oxide to fluorine in the leachate was 1.05:2, the mixture was reacted at 85° C. for 2 h, and filtered to obtain 19.69 g of calcium fluoride solid (content of 98%) and a mixed solution of sodium chloride and aluminum chloride (Al in the mixed solution was 1.05:2). 3+ Mass concentration is 0.36%);

[0081] Add 46.65 g of a 32 wt % sodium hydroxide solution to the sodium chloride and aluminum chloride mixture, wherein the molar ratio of aluminum element to sodium hydroxide in the mixture is 1:3, and perform a precipitation reaction at room temperature for 1 hour to obtain aluminum hydroxide solid and a sodium chloride solution;

[0082] Lithium slag (mainly composed of SiO2 53.17%, Al2O3 16.10%) and sodium hydroxide solution with a concentration of 25.76wt% were mixed in a mass ratio of 1:2.22, and a water glass reaction drum was used for heat preservation at 175°C for 5h. After filtering, a sodium silicate and sodium metaaluminate mixed solution with a Na2O content of 199.58g / L, a SiO2 content of 306.56g / L, and an Al2O3 content of 92.83g / L was obtained;

[0083] The prepared aluminum hydroxide solid, sodium silicate and sodium aluminate mixture and sodium hydroxide solution were mixed in a Na2O:SiO2:Al2O3 molar ratio of 1.3:2.06:1, crystallized at 81°C for 3 hours, and the slurry was separated, washed and dried to obtain 4A zeolite molecular sieve (static water adsorption of 24.8%).

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for synergistically preparing calcium fluoride and molecular sieves based on multiple industrial wastes, comprising the following steps: Cryolite, water, aluminum hydroxide and hydrochloric acid are mixed and acid leached to obtain a leachate; The leaching solution is mixed with a calcium compound to carry out a fluorine precipitation reaction to obtain a mixed solution of sodium chloride and aluminum chloride and a calcium fluoride solid; The sodium chloride and aluminum chloride mixed solution is mixed with an alkaline solution to perform a precipitation reaction to obtain aluminum hydroxide solid and a chloride salt solution; The lithium slag is mixed with a sodium hydroxide solution and subjected to an alkali treatment to obtain a mixed solution of sodium silicate and sodium metaaluminate; The aluminum hydroxide solid, sodium silicate and sodium metaaluminate mixed solution are mixed with a sodium hydroxide solution to carry out a crystallization reaction to obtain a 4A zeolite molecular sieve.

2. The method according to claim 1, characterized in that The fluorine content in the cryolite is 48-49.99 wt %, the mass concentration of the hydrochloric acid is 36-38%, and the purity of the aluminum hydroxide is 90-98%.

3. The method according to claim 2, characterized in that The molar ratio of the cryolite, aluminum hydroxide, hydrochloric acid and water is 1:(1.10-1.51):(5.13-9.02):(527.78-593.75); the acid leaching temperature is 80-95°C and the time is 1-3h.

4. The method according to claim 1, characterized in that The F in the leaching solution - The mass concentration is 0.84-1.35%, the calcium compound comprises one or more of calcium oxide, calcium carbonate and calcium hydroxide, and the ratio of the amount of the calcium compound to the amount of fluorine element substance in the leaching solution is 0.90-1.20:

2.

5. The method according to claim 1 or 4, characterized in that: The temperature of the fluorine deposition reaction is 70-90° C. and the time is 1-3 hours.

6. The method according to claim 1, characterized in that In the precipitation reaction step, the alkaline solution includes sodium hydroxide solution or ammonia water, and the mass concentration of the alkaline solution is 20-32%; the aluminum element in the sodium chloride and aluminum chloride mixture reacts with OH in the alkaline solution. - The amount of substance ratio is 1:2.80~3.

20.

7. The method according to claim 1 or 6, characterized in that: The temperature of the precipitation reaction is 20-40° C. and the time is 1-3 hours.

8. The method according to claim 1, characterized in that In terms of mass percentage, the components of the lithium slag include SiO2 45-55% and Al2O3 15-20%. In the alkali treatment step, the mass concentration of the sodium hydroxide solution is 20-32%; the temperature of the alkali treatment is 155-180° C., and the insulation time is 2-6 hours.

9. The method according to claim 1 or 8, characterized in that: In the mixed solution of sodium silicate and sodium aluminate, the content of Na2O is 160-260 g / L, the content of SiO2 is 200-350 g / L, and the content of Al2O3 is 80-110 g / L.

10. The method according to claim 1, characterized in that In the crystallization reaction step, the amount of the sodium hydroxide solution, aluminum hydroxide solid, and the mixed solution of sodium silicate and sodium aluminate satisfies the molar ratio of Na2O, SiO2 and Al2O3 of (0.95-1.35):(1.90-2.10):1, the temperature of the crystallization reaction is 75-85°C, and the time is 3-12h.