A method for full resource recycling of bayer process red mud

Abstract

The application provides a method for full resource recycling of Bayer process red mud, valuable elements such as aluminum, iron, calcium, silicon and gallium in the red mud are leached into a solution, main elements (aluminum, iron, calcium and silicon) are separated first to obtain industrial products such as iron ore powder, silica gel, gypsum and water purifying agent, and gallium elements are enriched, gallium is separated and extracted from the solution through extraction, the purpose of full resource recycling of the Bayer process red mud is achieved, high concentration enrichment of the gallium elements is realized, valuable elements are not wasted, and the method has the advantages of less interference factors, high extraction efficiency, saved extraction agent and back extraction agent.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of solid waste, and in particular to a method for the full resource recovery and utilization of Bayer process red mud. Background Technology

[0002] Red mud is a highly alkaline solid waste generated during the alumina smelting process from bauxite. Currently, approximately 1 to 1.5 tons of red mud are produced for every ton of alumina produced. Red mud contains valuable elements such as aluminum, iron, calcium, silicon, and gallium, and can be used as a secondary resource. However, because gallium is a rare earth element, its content is very low compared to the major elements in red mud. Current technologies make it difficult to directly enrich gallium at high concentrations, and even more difficult to simultaneously enrich gallium and extract and recover other elements from the red mud to achieve comprehensive resource utilization. Summary of the Invention

[0003] Based on the above situation, the main objective of this invention is to provide a method for the full resource recovery and utilization of Bayer process red mud, which can enrich gallium elements while realizing the comprehensive utilization of the full resource of red mud.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for the complete resource recovery and utilization of Bayer process red mud includes the following steps:

[0006] S100: Add sulfuric acid solution and an inert-coated magnet to Bayer red mud. After a first predetermined time at room temperature, remove the magnet that has adsorbed Fe3O4. After a second predetermined time at a first predetermined temperature, filter and separate the contents to obtain filtrate A and a first filter residue containing CaSO4.

[0007] S200: The filtrate A is aged at a second predetermined temperature. After a third predetermined reaction time, it is filtered and separated to obtain filtrate B and a second filter residue. The second filter residue is washed to obtain silica gel.

[0008] S300: The chelating resin is placed in the filtrate B to adsorb Ga element. After adsorption at a third predetermined temperature for a fourth predetermined time, the resin and filtrate C are separated by filtration to obtain the adsorbed resin and filtrate C. The resin is then rinsed with water, and the liquid obtained during the rinsing process is collected to obtain the rinsing solution.

[0009] S310: After adding a first alkaline solution to the filtrate C until the pH value of the mixed liquid rises to any value in the range [3, 4], the filtrate C spontaneously reacts to obtain polyaluminum ferric sulfate water purification agent;

[0010] S400: Add a second alkaline solution to the rinsing solution and react until the pH value of the liquid becomes any value in the range [9, 10]. Then stop adding the second alkaline solution, let it stand for a fifth predetermined time, and then filter to separate the liquid to obtain filtrate D and third filter residue.

[0011] S410: During the sixth predetermined time, CO2 is continuously introduced into the filtrate D to react and separate by filtration, and a fourth filter residue containing Al(OH)3 is obtained, which can be used to obtain Al2O3 by subsequent calcination.

[0012] S500: Add sulfuric acid solution to the third filter residue, heat to a fourth predetermined temperature, carry out a aging reaction, react for a seventh predetermined time, and obtain an aged sample;

[0013] S600: The matured sample is stirred and soaked in water at a fifth predetermined temperature. After stirring for an eighth predetermined time, it is filtered and separated to obtain filtrate E and fifth filter residue containing Fe2O3.

[0014] S700: An extractant is added to the filtrate E, and after extraction at a sixth predetermined temperature for a ninth predetermined time, ammonium sulfate is added as a back-extraction agent for a tenth predetermined time, followed by filtration and separation. The resulting filtrate F is a Ga-enriched solution.

[0015] Preferably, in step S100, the concentration of the sulfuric acid solution is 5 mol / L to 12 mol / L, and the first predetermined temperature is room temperature to 40°C.

[0016] The inert coating is polytetrafluoroethylene, the magnetic field strength of the magnet is 0.05T to 0.10T, and the first predetermined time is 2-10min;

[0017] The second predetermined time is 3h to 5h, and the liquid-solid mass ratio of the sulfuric acid solution and the Bayer red mud is 5:1 to 10:1.

[0018] Preferably, in step S200, the second predetermined temperature is 60℃~100℃, and the third predetermined time is 40~80min.

[0019] Preferably, in step S300, the third predetermined temperature is 40℃~60℃, and the fourth predetermined time is 15~20h.

[0020] Preferably, in step S310, the first alkaline solution is a sodium hydroxide solution or an ammonia solution, the temperature of the spontaneous reaction is 65-85°C, and the time of the spontaneous reaction is 2-4 hours.

[0021] Preferably, in step S400, the second alkaline solution is a 75% sodium hydroxide solution, and the addition of the sodium hydroxide solution is stopped when the pH value of the liquid becomes 9.5, and the fifth predetermined time is 8 to 12 hours.

[0022] Preferably, in step S410, the sixth predetermined time is 2 to 3 minutes, and the CO2 pressure is 35 to 40 mmHg.

[0023] Preferably, in step S500, the concentration of the sulfuric acid solution is 5 mol / L to 12 mol / L, the liquid-solid ratio of the sulfuric acid solution to the third filter residue is 2:1 to 3:1, the fourth predetermined temperature is 180℃ to 200℃, and the seventh predetermined time is 2h to 3h.

[0024] Preferably, in step S600, the fifth predetermined temperature is 80℃~100℃, and the eighth predetermined time is 1h~2h.

[0025] Preferably, the extractant is n-propanol, the volume fraction of n-propanol is 25% to 35%, the mass fraction of the back-extraction agent is 30% to 40%, the ninth predetermined time and the tenth predetermined time are both 15 min to 30 min, and the sixth predetermined temperature is room temperature.

[0026] This invention discloses a method for the full resource recovery and utilization of Bayer process red mud. First, valuable elements such as aluminum, iron, calcium, and silicon are extracted from the red mud to obtain industrial products such as iron ore powder, silica gel, gypsum, and water purification agents. Then, gallium is extracted from the remaining materials using an extraction method, achieving high-concentration enrichment of gallium. This method avoids wasting valuable elements, minimizes interference during the final gallium extraction, achieves high extraction efficiency, and saves on the amount of extractant and back-extraction agent used. Furthermore, the entire process is simple, requires no special equipment, has low energy consumption, and is highly environmentally friendly and conducive to the health of operators, making it easily industrializable. This method not only achieves large-scale reduction of red mud but also opens up new avenues for the comprehensive and economically efficient utilization of Bayer process red mud, achieving optimal overall technical results with low total cost and abundant effective materials, truly turning waste into treasure.

[0027] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the drawings:

[0029] Figure 1A flowchart illustrating a preferred embodiment of the method for full resource recovery and utilization of Bayer red mud provided by the present invention;

[0030] Figure 2 A flowchart illustrating another preferred embodiment of the method for full resource recovery and utilization of Bayer red mud provided by the present invention;

[0031] Figure 3 This is a flowchart of another preferred embodiment of the method for full resource recovery and utilization of Bayer red mud provided by the present invention. Detailed Implementation

[0032] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0033] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0034] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0035] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] With attachment Figure 1 For example, the method for full resource recovery and utilization of Bayer process red mud provided by this invention includes the following steps:

[0037] S100: Sulfuric acid solution and an inert-coated magnet are added to Bayer red mud. After a first predetermined time at room temperature, the magnet adsorbed with Fe3O4 is removed. After a second predetermined time at a first predetermined temperature, the mixture is filtered to obtain filtrate A and a first filter residue containing CaSO4. The reaction process mainly includes:

[0038] Al₂O₃ + 6H₂O + →2Al 3+ +3H2O;

[0039] Fe2O3+6H + →2Fe 3+ +3H2O;

[0040] Ga2O3 + 6H + →2Ga 3+ +3H2O;

[0041] Ga(OH)3+3H + →Ga 3+ +3H2O;

[0042] SiO4 - +4H + →H4SiO4↓;

[0043] H4SiO4→H2SiO3+H2O;

[0044] S200: The filtrate A is subjected to an aging reaction at a second predetermined temperature. After a third predetermined reaction time, it is filtered to obtain filtrate B and a second filter residue. The second filter residue is washed to obtain silica gel. The aging reaction process includes:

[0045] H2SiO3+mH2O→SiO2·(m+1)H2O;

[0046] S300: The chelating resin is placed in the filtrate B to adsorb Ga element. After adsorption at a third predetermined temperature for a fourth predetermined time, the resin and filtrate C are separated by filtration to obtain the adsorbed resin and filtrate C. The resin is then rinsed with water, and the liquid obtained during the rinsing process is collected to obtain the rinsing solution.

[0047] S310: After adding a first alkaline solution to the filtrate C until the pH value of the mixed liquid rises to any value in the range [3, 4], a spontaneous reaction occurs inside the filtrate C to obtain polyaluminum ferric sulfate water purification agent, wherein the reaction process includes:

[0048] 2Al₂(SO₄)₃ + 2nH₂O → 2Al₂(OH)₃ n (SO4) 3-n / 2 +nH2SO4;

[0049] 2Fe₂(SO₄)₃ + 2nH₂O → 2Fe₂(OH)₃ n (SO4) 3-n / 2 +nH2SO4;

[0050] m[Al2(OH) n (SO4) 3-n / 2 ]=[Al2(OH) n (SO4) 3-n / 2 ]m;

[0051] m[Fe2(OH) n (SO4) 3-n / 2 ]=[Fe2(OH)n (SO4) 3-n / 2 ]m;

[0052] S400: A second alkaline solution is added to the eluent to react until the pH value of the liquid becomes any value in the range [9, 10]. Then, the addition of the second alkaline solution is stopped, and the mixture is allowed to stand for a predetermined time. After standing, filtration is performed to separate the residue and obtain filtrate D and a third filter residue. The reaction process includes:

[0053] Al 3+ +4OH - →AlO2 - +2H2O;

[0054] Ga 3+ +3OH - →Ga(OH)3↓;

[0055] Fe 3+ +3OH - →Fe(OH)3↓;

[0056] S410: During the sixth predetermined time, CO2 is continuously introduced into the filtrate D to react and separate by filtration, and a fourth filter residue containing Al(OH)3 is obtained, which can be used to obtain Al2O3 by subsequent calcination.

[0057] S500: Add sulfuric acid solution to the third filter residue, and carry out a ripening reaction at a fourth predetermined temperature for a seventh predetermined time, wherein the reaction process includes:

[0058] Ga(OH)3+3H + →Ga 3+ +3H2O;

[0059] 3H2SO4+2Fe(OH)3→Fe2(SO4)3+6H2O;

[0060] Fe2(SO4)3→Fe2O3+3SO3↑;

[0061] S600: The ripened sample obtained in step S500 is stirred and soaked in water at a fifth predetermined temperature. After stirring for an eighth predetermined time, it is filtered and separated to obtain filtrate E and fifth filter residue containing Fe2O3.

[0062] S700: An extractant is added to the filtrate E, and after extraction at a sixth predetermined temperature for a ninth predetermined time, ammonium sulfate is added as a back-extraction agent for a tenth predetermined time, followed by filtration and separation. The resulting filtrate F is a Ga-enriched solution.

[0063] Specifically, in step S100, the inert coating on the magnet protects it from corrosion by sulfuric acid solution without affecting its magnetic attraction. Since some iron in the Bayer process red mud exists in the form of Fe3O4, and Fe3O4 has an inverse spinel structure, it is difficult to react with acid at room temperature, especially under sulfuric acid conditions. Therefore, it can be quickly adsorbed by a magnet (for a first predetermined adsorption time), and then the magnet can be removed. The Fe3O4 in the Bayer process red mud is also adsorbed and removed along with the magnet. This portion of Fe3O4 can be washed and dried to obtain iron ore powder, which can be sold as an industrial raw material or used in other industries.

[0064] The Bayer process red mud mainly consists of agglomerated particles coated with amorphous substances. The main elements on the outer layer of these agglomerated particles are aluminum, iron, and silicon. In step S100, aluminum oxide, iron oxide, gallium oxide, and gallium hydroxide in the Bayer process red mud can all react with sulfuric acid solution. Silicate ions in the Bayer process red mud can also react with hydrogen ions in the sulfuric acid solution to form orthosilicic acid, which is then hydrolyzed to obtain silicic acid. Therefore, in filtrate A, the main element derived from the red mud is Al. 3+ Fe 3+ Ga 3+ SiO3 2+ It exists in the form of.

[0065] Because calcium, another major element in Bayer process red mud, is mainly found inside agglomerated particles, primarily in the forms of nepheline (Na4Ca(AlSiO4)4) and katoite (Ca3Al2(SiO4)(OH)8), after reacting with sulfuric acid, elements such as Al and Si are reduced to Al as the precursor. 3+ SiO3 2- The calcium sulfate exists in the filtrate in the form of CaSO4, and the Ca element exists in the filter residue in the form of CaSO4. Therefore, the main component of the first filter residue is CaSO4. The first filter residue can be directly recycled as a gypsum raw material. Since the valuable elements and silicon elements exist in the acid solution in the form of ions, the obtained calcium sulfate is of high purity and can be sold as an industrial raw material or used in other industries.

[0066] In step S200, H in filtrate A + SiO3 2+ At a suitable temperature (i.e., the second predetermined temperature), the aging reaction with water molecules proceeds for a sufficient time (i.e., the third predetermined time). The water molecules required for the aging reaction can be provided by the water contained in filtrate A. After the sufficient aging time, colloidal silica gel can be obtained through filtration and separation. After drying, it can be sold or used as an industrial raw material. Meanwhile, in filtrate B, the aluminum, iron, and gallium elements from the red mud continue to exist primarily as Al. 3 + Fe3+ and Ga 3+ It exists in the form of.

[0067] In step S300, a neutral macroporous chelating resin containing amino or oxime groups (such as LSC-500S aminophosphonic acid macroporous chelating resin and LSC-600 amine oxime chelating resin) can be used as an adsorbent for gallium ions. The principle of gallium ion adsorption is that the N, O, and S atoms in the active functional groups (such as =NOH, -NH2, -OH, -SH, =NH, etc.) of the chelating resin itself have unbonded lone pairs of electrons. These pairs can form coordinate bonds with gallium ions, which have empty orbitals due to the loss of their outermost electrons, forming a stable structure similar to a small molecule complex, thereby achieving the extraction and separation of gallium ions. Taking the case where the chelating resin contains the [-NH-CH2-P(O)(OH)2] group as an example, this resin forms a stable complex with metal ions, exhibiting excellent selective adsorption performance for gallium. The specific reaction is as follows:

[0068] R-NH-CH2-PO(OH)2+2[Ga(SO4)2] - →R-NH-CH2-PO-O2-[Ga2(SO4)3]+H2SO4

[0069] The chelating resin in Ga 3+ After adsorption saturation, a small amount of Fe will inevitably still be adsorbed. 3+ And Al 3+ Therefore, the eluent contains saturated Ga. 3+ It also contains a small amount of Fe. 3+ And Al 3+ Subsequent processing is used to remove as much of this Fe as possible. 3+ And Al 3+ This allows for the recycling of iron and aluminum elements.

[0070] As for the Fe remaining in the filtrate C 3+ And Al 3+ It can be used to prepare polyaluminum ferric sulfate water purifier, i.e., proceed to step S310. The preparation of polyaluminum ferric sulfate water purifier requires a suitable pH environment, so the pH of the filtrate C is first adjusted to between 3 and 4, and the reaction is carried out under suitable temperature conditions for an appropriate time to obtain polyaluminum ferric sulfate solution (polyaluminum ferric sulfate is a mixture of aluminum sulfate polymer and ferric sulfate polymer). This solution can be used directly as a water purifier, or it can be evaporated, cooled, and ground to obtain solid water purifier powder, which has the same ultra-high water purification capacity.

[0071] In step S400, a second alkaline solution and Ga are added to the rinsing solution. 3+ Fe3+ And Al 3+ In the reaction, aluminum is converted into AlO2. - It exists in the form of filtrate D, while Ga 3+ and Fe 3+ It exists in the third filter residue in the form of Ga(OH)3 precipitate and Fe(OH)3 precipitate, respectively.

[0072] In step S410, CO2 is continuously introduced into the filtrate D for a suitable time (sixth predetermined time) to react and obtain a fourth filter residue mainly containing Al(OH)3. This fourth filter residue is used to obtain Al2O3 by subsequent calcination. Alumina, as an industrial raw material, can be sold or used in other industries.

[0073] In step S500, before adding the sulfuric acid solution for aging, a predetermined amount of water can be added first. This is because the filter residue inevitably still contains a small amount of Si (although silicon has been specifically extracted in the previous step S200, those skilled in the art will understand that no extraction can achieve 100% purity). Adding a predetermined amount of water makes the silica gel generated after adding the sulfuric acid solution more dispersed, thereby minimizing the impact on subsequent gallium extraction. Simultaneously, the presence of water facilitates the release of a large amount of heat during the dilution of the sulfuric acid solution upon addition, which is beneficial to the aging process. The fourth predetermined temperature required for aging can be continuously provided by maintaining an external oil bath environment (such as using glycerol or polyethylene glycol heated to the fourth predetermined temperature) for a seventh predetermined time. After the seventh predetermined reaction time, no filtration separation is required; the product of this step (excluding gaseous SO3) is the aging sample.

[0074] In step S600, the main purpose of stirring and leaching is to leach gallium ions from the aging sample, so that gallium enrichment can proceed more smoothly in step S700. The preferred weight ratio of water to aging sample in step S600 is 20:1 to 3:1. In the filtrate E, the main element from the red mud is gallium, existing in the form of Ga. 3+ It also contains a small amount of iron, in the form of Fe. 3+ The fifth filter residue, mainly containing iron oxide, can be dried to obtain iron ore powder, which can then be sold as an industrial raw material or used in other industrial sectors. During the aging process, some of the iron is present in the filtrate and some in the filter residue. Due to the aforementioned iron removal steps, the iron content in the solution at this point is very low (Fe2+). 3+ The content of [a certain substance] is less than 100 mg / L, so its effect on the subsequent extraction process is negligible.

[0075] In step S700, n-propanol is preferably used as the extractant because sulfuric acid solution was added in the previous step, so the filtrate E is an acidic environment. In this acidic environment, the extractant is protonated to form cations, Ga 3+ It reacts with sulfate ions in filtrate E to form a complex anion [Ga(SO4)2]. - Under suitable temperature conditions (i.e., the sixth predetermined temperature) and after a suitable extraction time (i.e., the ninth predetermined time), the two interact and associate in solution to form a combined reactant. Then, through back-extraction for a suitable time (the tenth predetermined time), the addition of a back-extraction agent reduces the acidity of the acidic environment, allowing the anion [Ga(SO4)2] to be released. - Decomposition, Ga 3+ The ions re-enter the aqueous phase, resulting in a gallium-rich solution. Taking n-propanol as the extractant as an example, the extraction and back-extraction reactions include:

[0076] Ga 3+ +2SO4 2- →[Ga(SO4)2] -

[0077] 2CH3(CH2)2OH+H2SO4→2CH3(CH2)2OHH + +SO4 2-

[0078] CH3(CH2)2OHH + +[Ga(SO4)2] - →CH3(CH2)2O HH + ·[Ga(SO4)2] -

[0079] CH3(CH2)2O HH + ·[Ga(SO4)2] - →Ga 3+ +CH3(CH2)2O HH + +2SO4 2-

[0080] Those skilled in the art will understand that, since there is no sequential constraint between step S310 and steps S400, S410, S500, S600, and S700, step S310 does not necessarily have to follow immediately after S300. It can be performed after S300, or even as the last step of this method (see Appendix). Figure 2 Step S410 does not necessarily have to follow S300 immediately; it can be performed after S400, or even as the last step of this method (see Appendix). Figure 3 ).

[0081] This invention discloses a method for the full resource recovery and utilization of Bayer process red mud. First, valuable elements such as aluminum, iron, calcium, and silicon are extracted from the red mud to obtain industrial products such as iron ore powder, silica gel, and gypsum. Then, gallium is extracted from the remaining material using an extraction method, achieving high-concentration enrichment of gallium. This method avoids wasting valuable elements, minimizes interference during the final gallium extraction, achieves high extraction efficiency, and saves on the amount of extractant and back-extraction agent used. Furthermore, the entire process is simple, requires no special equipment, has low energy consumption, and is highly environmentally friendly and conducive to the health of operators, making it easily industrializable. This method not only achieves large-scale reduction of red mud but also opens up new avenues for the comprehensive and economically efficient utilization of Bayer process red mud, achieving optimal overall technical results with low total cost and abundant effective materials, truly turning waste into treasure.

[0082] Gallium has a wide range of applications, such as being used in the manufacture of optical glass, vacuum tubes, and as a raw material for semiconductors; it can be used to measure high temperatures when placed in quartz thermometers; it can be added to aluminum to create easily heat-treatable alloys; gallium-gold alloys are also used in decoration and dental prosthetics; gallium is also used as a catalyst in organic synthesis; and it can be used in the semiconductor industry, for example, in the manufacture of light-emitting diodes (LEDs) and gallium arsenide laser diodes. This invention achieves the complete resource recovery and utilization of Bayer process red mud while also achieving a high degree of gallium enrichment, providing extremely favorable preliminary conditions for subsequent purification of metallic gallium, and has significant application value.

[0083] Preferably, in step S100, the concentration of the sulfuric acid solution is 5 mol / L to 12 mol / L, and the first predetermined temperature is room temperature to 40°C.

[0084] The inert coating is polytetrafluoroethylene, the magnetic field strength of the magnet is 0.05T to 0.10T, and the first predetermined time is 2-10min;

[0085] The second predetermined time is 3h to 5h, and the liquid-solid mass ratio of the sulfuric acid solution and the Bayer red mud is 5:1 to 10:1.

[0086] Specifically, by setting the above-mentioned parameters, it can be ensured that the amount, concentration, reaction temperature, and reaction time of the sulfuric acid solution are sufficient to facilitate the occurrence of the relevant reaction without causing waste.

[0087] Polytetrafluoroethylene (PTFE) is inexpensive and provides ample protection for magnets without affecting their magnetic attraction, making it a preferred inert coating material. By selecting the magnetic field strength and attraction time, the magnet can be made to adsorb Fe3O4 from Bayer process red mud as fully as possible, improving the purification effect.

[0088] Preferably, in step S200, the second predetermined temperature is 60℃~100℃, and the third predetermined time is 40~80min.

[0089] By maintaining the second predetermined temperature for a third predetermined time period, the aging reaction can be ensured to occur fully without wasting heat resources.

[0090] Preferably, in step S300, the third predetermined temperature is 40℃~60℃, and the fourth predetermined time is 15~20h.

[0091] By maintaining the aforementioned third predetermined temperature through heating for a fourth predetermined time period, it is possible to ensure that the adsorption of gallium elements is fully carried out without wasting heat resources.

[0092] Preferably, in step S310, the first alkaline solution is a sodium hydroxide solution or an ammonia solution, the reaction temperature is 65-85°C, and the reaction time is 2-4 hours.

[0093] Experiments have shown that adjusting the pH of the filtrate C with sodium hydroxide solution or ammonia solution not only effectively regulates the pH but also facilitates the subsequent spontaneous reaction that generates polyaluminum ferric sulfate water purifier. The preferred mass fraction of sodium hydroxide in the sodium hydroxide solution is 30%-45%, and the preferred concentration of the ammonia solution is 25%-28%.

[0094] Preferably, in step S400, the second alkaline solution is a 75% sodium hydroxide solution, and the addition of the sodium hydroxide solution is stopped when the pH value of the liquid becomes 9.5, and the fifth predetermined time is 8 to 12 hours.

[0095] A sodium hydroxide solution with a concentration as high as 75% can quickly adjust the pH of the rinsing solution to 9.5. The selection of the fifth predetermined time mentioned above ensures that the relevant reactions in step S400 proceed fully.

[0096] Preferably, in step S410, the sixth predetermined time is 2 to 3 minutes, and the CO2 pressure is 35 to 40 mmHg.

[0097] The sixth predetermined time and the selection of CO2 pressure can ensure that the relevant reactions in this step proceed fully and smoothly, without wasting CO2 gas resources.

[0098] Preferably, in step S500, the concentration of the sulfuric acid solution is 5 mol / L to 12 mol / L, the liquid-solid ratio of the sulfuric acid solution to the third filter residue is 2:1 to 3:1, the fourth predetermined temperature is 180℃ to 200℃, and the seventh predetermined time is 2h to 3h.

[0099] By setting the relevant parameters in this step, it can be ensured that the amount, concentration, reaction temperature, and reaction time of the sulfuric acid solution are sufficient, facilitating the smooth occurrence of the relevant reactions in this step.

[0100] Preferably, in step S600, the fifth predetermined temperature is 80℃~100℃ and the eighth predetermined time is 1h~2h, which facilitates the thorough mixing of the ripened sample with water and improves the convenience of subsequent gallium extraction.

[0101] Preferably, the extractant is n-propanol, the volume fraction of n-propanol is 25% to 35%, the mass fraction of the back-extraction agent is 30% to 40%, the ninth predetermined time and the tenth predetermined time are both 15 min to 30 min, and the sixth predetermined temperature is room temperature, so that the extraction and back-extraction can be carried out smoothly and effectively, thereby improving the enrichment degree of gallium element in the final obtained solution.

[0102] Example 1:

[0103] S100: Add a 5 mol / L sulfuric acid solution and a CXG-99 magnetic separator with an inert coating and a magnetic field strength of 0.05T to the Bayer red mud. The liquid-solid mass ratio of the sulfuric acid solution to the red mud is 10:1. After 5 minutes at room temperature, remove the magnetic separator containing Fe3O4, heat it to 40°C and then let it sit for 5 hours. Then filter and separate the contents to obtain filtrate A and a first filter residue containing CaSO4.

[0104] S200: The filtrate A is aged at 60°C for 40 minutes, and then filtered to obtain filtrate B and a second filter residue. The second filter residue is washed to obtain silica gel.

[0105] S300: Neutral macroporous chelating resin is placed in the filtrate B to adsorb Ga element. After adsorption at 60°C for 20 hours, the resin and filtrate C are separated by filtration. The resin is then rinsed with water, and the liquid obtained during the rinsing process is collected to obtain the rinsing solution.

[0106] S310: Add a 35% sodium hydroxide solution to the filtrate C until the pH of the mixed liquid rises to 3. The filtrate C undergoes a spontaneous reaction to obtain polyaluminum ferric sulfate water purification agent. The reaction temperature is 65℃ and the reaction time is 2h.

[0107] S400: Add an appropriate amount of 75% sodium hydroxide solution to the rinsing solution and react until the pH value of the liquid becomes 9.5. Then stop adding the sodium hydroxide solution, let it stand for 8 hours, and then filter to separate the filtrate D and the third filter residue.

[0108] S410: Within 2 minutes, CO2 at a pressure of 38 mmHG is continuously introduced into the filtrate D to react and separate it by filtration, and a fourth filter residue containing Al(OH)3 is obtained, which can be used to obtain Al2O3 by subsequent calcination.

[0109] S500: Add a 5 mol / L sulfuric acid solution to the third filter residue, wherein the liquid-to-solid ratio of the sulfuric acid solution to the third filter residue is 3:1, heat to 200°C, and carry out a aging reaction for 3 hours to obtain an aging sample;

[0110] S600: The aging sample obtained in step S500 is stirred and soaked in water at 90°C. After stirring for 2 hours, it is filtered and separated to obtain filtrate E and the fifth filter residue containing Fe2O3.

[0111] S700: Add 35% n-propanol extractant to the filtrate E, extract for 30 min at room temperature, then add 40% ammonium sulfate as back-extraction agent for 15 min, and then filter to separate. The resulting filtrate F is a Ga enrichment solution.

[0112] Analysis of the products obtained above revealed that the CaSO4 content in the first filter residue obtained in step S100 is greater than 95%, meeting the requirements of standard GB / T 5483-2008 "Natural Gypsum"; the silica gel obtained in step S200 has a purity of 93.02%, meeting the requirements of standard GB / T 2881-2014 "Industrial Silicon"; the polyaluminum ferric sulfate water purifier obtained in step S310 has a turbidity removal rate greater than 93.94%, meeting the requirements of standard HG / T 5565-2019 "Water Treatment Agent Aluminum Ferric Sulfate"; and the fourth filter residue containing Al(OH)3 obtained in step S410, after calcination, yields Al2O3 with a purity of 97.21%, meeting the requirements of standard GB / T 24487-2009 "Alumina".

[0113] Example 2:

[0114] S100: Add a 12 mol / L sulfuric acid solution and a CXG-99 magnetic separator with an inert coating and a magnetic field strength of 0.08T to the Bayer red mud. The liquid-solid mass ratio of the sulfuric acid solution to the red mud is 5:1. After 2 minutes at room temperature, remove the magnetic separator containing Fe3O4, heat it to 30°C and then let it sit for 3 hours. Then filter and separate the contents to obtain filtrate A and a first filter residue containing CaSO4.

[0115] S200: The filtrate A is aged at 100°C for 80 minutes, and then filtered to obtain filtrate B and a second filter residue. The second filter residue is washed to obtain silica gel.

[0116] S300: Neutral macroporous chelating resin is placed in the filtrate B to adsorb Ga element. After adsorption at 40°C for 15 hours, the resin and filtrate C are separated by filtration. The resin is then rinsed with water, and the liquid obtained during the rinsing process is collected to obtain rinsing solution.

[0117] S310: Add a 26% ammonia solution to the filtrate C until the pH of the mixed liquid rises to 3. The filtrate C undergoes a spontaneous reaction to obtain polyaluminum ferric sulfate water purification agent. The reaction temperature is 75℃ and the reaction time is 3h.

[0118] S400: Add an appropriate amount of 75% sodium hydroxide solution to the rinsing solution and react until the pH value of the liquid becomes 9.5. Then stop adding the sodium hydroxide solution, let it stand for 10 hours, and then filter to separate the filtrate D and the third filter residue.

[0119] S410: Within 2 minutes, CO2 at a pressure of 35 mmHG is continuously introduced into the filtrate D to react and separate it by filtration, and a fourth filter residue containing Al(OH)3 is obtained, which can be used to obtain Al2O3 by subsequent calcination.

[0120] S500: Add a sulfuric acid solution with a concentration of 12 mol / L to the third filter residue, wherein the liquid-solid ratio of the sulfuric acid solution to the third filter residue is 2:1, heat to 180°C, and carry out a aging reaction for 2 hours to obtain an aging sample;

[0121] S600: The aging sample obtained in step S500 is stirred and soaked in water at 90°C. After stirring for 1 hour, it is filtered and separated to obtain filtrate E and the fifth filter residue containing Fe2O3.

[0122] S700: Add 25% n-propanol extractant to the filtrate E, extract for 15 min at room temperature, then add 35% ammonium sulfate as back-extraction agent for 25 min, and then filter to separate. The resulting filtrate F is a Ga enrichment solution.

[0123] Analysis of the products obtained above revealed that the CaSO4 content in the first filter residue obtained in step S100 is greater than 95%, meeting the requirements of standard GB / T 5483-2008 "Natural Gypsum"; the silica gel obtained in step S200 has a purity of 92.72%, meeting the requirements of standard GB / T 2881-2014 "Industrial Silicon"; the polyaluminum ferric sulfate water purifier obtained in step S310 has a turbidity removal rate greater than 95.89%, meeting the requirements of standard HG / T 5565-2019 "Water Treatment Agent Aluminum Ferric Sulfate"; and the fourth filter residue containing Al(OH)3 obtained in step S410, after calcination, yields Al2O3 with a purity of 98.89%, meeting the requirements of standard GB / T 24487-2009 "Alumina".

[0124] Example 3:

[0125] S100: Add a 10 mol / L sulfuric acid solution and a CXG-99 magnetic separator with an inert coating and a magnetic field strength of 0.1T to the Bayer red mud. The liquid-solid mass ratio of the sulfuric acid solution to the red mud is 8:1. After 4 minutes at room temperature, remove the magnetic separator containing Fe3O4. After another 4 hours at 25°C, filter and separate the residue to obtain filtrate A and a first filter residue containing CaSO4.

[0126] S200: The filtrate A is aged at 80°C for 60 minutes. After filtration, filtrate B and second filter residue are obtained. The second filter residue is washed to obtain silica gel.

[0127] S300: Neutral macroporous chelating resin is placed in the filtrate B to adsorb Ga element. After adsorption at 50°C for 18 hours, the resin and filtrate C are separated by filtration. The resin is then rinsed with water, and the liquid obtained during the rinsing process is collected to obtain rinsing solution.

[0128] S310: Add a 40% sodium hydroxide solution to the filtrate C until the pH of the mixed liquid rises to 4. The filtrate C undergoes a spontaneous reaction to obtain polyaluminum ferric sulfate water purification agent. The reaction temperature is 85℃ and the reaction time is 4h.

[0129] S400: Add an appropriate amount of 75% sodium hydroxide solution to the rinsing solution and react until the pH value of the liquid becomes 9.5. Then stop adding the sodium hydroxide solution, let it stand for 12 hours, and then filter to separate the filtrate D and the third filter residue.

[0130] S410: Within 2 minutes, CO2 at a pressure of 40 mmHG is continuously introduced into the filtrate D to react and separate it by filtration, and a fourth filter residue containing Al(OH)3 is obtained, which can be used to obtain Al2O3 by subsequent calcination.

[0131] S500: Add a 10 mol / L sulfuric acid solution to the third filter residue, wherein the liquid-to-solid ratio of the sulfuric acid solution to the third filter residue is 3:1, heat to 200°C, and carry out a aging reaction for 2.5 hours to obtain an aging sample;

[0132] S600: The ripened sample obtained in step S500 is stirred and soaked in water at 90°C. After stirring for 1.5 hours, it is filtered and separated to obtain filtrate E and the fifth filter residue containing Fe2O3.

[0133] S700: Add 30% n-propanol extractant to the filtrate E, extract for 25 min at room temperature, then add 38% ammonium sulfate as back-extraction agent for 20 min, and then filter to separate. The resulting filtrate F is a Ga enrichment solution.

[0134] Analysis of the products obtained above revealed that the CaSO4 content in the first filter residue obtained in step S100 is greater than 95%, meeting the requirements of standard GB / T 5483-2008 "Natural Gypsum"; the silica gel obtained in step S200 has a purity of 92.33%, meeting the requirements of standard GB / T 2881-2014 "Industrial Silicon"; the polyaluminum ferric sulfate water purifier obtained in step S310 has a turbidity removal rate greater than 94.11%, meeting the requirements of standard HG / T 5565-2019 "Water Treatment Agent Aluminum Ferric Sulfate"; and the fourth filter residue containing Al(OH)3 obtained in step S410, after calcination, yields Al2O3 with a purity of 97.39%, meeting the requirements of standard GB / T 24487-2009 "Alumina".

[0135] Those skilled in the art will understand that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0136] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A method for full resource recycling of Bayer process red mud, characterized in that, The method comprises the following steps: S100: adding a sulfuric acid solution and a magnet with an inert coating into the Bayer process red mud, taking out the magnet with adsorbed Fe3O4 after a first predetermined time at room temperature, performing a filtration separation at a first predetermined temperature for a second predetermined time, and obtaining a filtrate A and a first filter residue containing CaSO4; S200: performing an aging reaction on the filtrate A at a second predetermined temperature for a third predetermined time, performing a filtration separation, obtaining a filtrate B and a second filter residue, and washing the second filter residue to obtain silica gel; S300: placing a chelating resin into the filtrate B to adsorb Ga elements, performing a filtration separation after a fourth predetermined time at a third predetermined temperature, obtaining the adsorbed resin and a filtrate C, and performing a water elution on the resin, collecting the liquid obtained in the elution process to obtain an elution liquid; S310: adding a first alkaline solution into the filtrate C until the pH value of the mixed liquid increases to any value in the interval [3, 4], and then allowing the filtrate C to spontaneously react to obtain a polyaluminum ferric sulfate water purifying agent; S400: adding a second alkaline solution into the elution liquid to react until the pH value of the liquid becomes any value in the interval [9, 10], stopping the addition of the second alkaline solution, and performing a filtration separation after a fifth predetermined time to obtain a filtrate D and a third filter residue; S410: continuously introducing CO2 into the filtrate D to react for a sixth predetermined time, performing a filtration separation, and obtaining a fourth filter residue containing Al(OH)3 for subsequent preparation of Al2O3 by calcination; S500: adding a sulfuric acid solution into the third filter residue, heating to a fourth predetermined temperature, performing a ripening reaction for a seventh predetermined time, and obtaining a ripened sample; S600: performing a stirring water immersion on the ripened sample at a fifth predetermined temperature for a eighth predetermined time, performing a filtration separation, and obtaining a filtrate E and a fifth filter residue containing Fe2O3; S700: adding an extractant into the filtrate E at a sixth predetermined temperature, extracting for a ninth predetermined time, adding ammonium sulfate as a back-extracting agent to perform back-extraction for a tenth predetermined time, and performing a filtration separation to obtain a filtrate F which is a Ga element enrichment solution.

2. The method of claim 1, wherein, In the step S100, the concentration of the sulfuric acid solution is 5 mol / L-12 mol / L, the first predetermined temperature is room temperature-40℃, The inert coating is polytetrafluoroethylene, the magnetic field strength of the magnet is 0.05T-0.10T, and the first predetermined time is 2-10min; The second predetermined time is 3h-5h, and the liquid-solid mass ratio of the sulfuric acid solution and the Bayer process red mud is 5:1-10:

1.

3. The method of claim 1, wherein, In the step S200, the second predetermined temperature is 60℃-100℃, and the third predetermined time is 40-80min.

4. The method of claim 1, wherein, In the step S300, the third predetermined temperature is 40℃-60℃, and the fourth predetermined time is 15-20h.

5. The method of claim 1, wherein, In the step S310, the first alkaline solution is sodium hydroxide solution or ammonia solution, the temperature of the spontaneous reaction is 65-85℃, and the time of the spontaneous reaction is 2-4h.

6. The method of claim 1, wherein, In the step S400, the second alkaline solution is sodium hydroxide solution with a concentration of 75%, the addition of the sodium hydroxide solution is stopped when the pH value of the liquid becomes 9.5, and the fifth predetermined time is 8-12h.

7. The method of claim 1, wherein, In the step S410, the sixth predetermined time is 2-3min, and the gas pressure of CO2 is 35-40mmHg.

8. The method of claim 1, wherein, In the step S500, the concentration of the sulfuric acid solution is 5-12mol / L, the liquid-solid ratio of the sulfuric acid solution to the third filter residue is 2:1-3:1, the fourth predetermined temperature is 180-200℃, and the seventh predetermined time is 2-3h.

9. The method of claim 1, wherein, In the step S600, the fifth predetermined temperature is 80-100℃, and the eighth predetermined time is 1-2h.

10. The method of claim 1, wherein, The extractant is n-propanol, the volume fraction of the n-propanol is 25-35%, the mass fraction of the back extractant is 30-40%, the ninth and tenth predetermined times are both 15-30min, and the sixth predetermined temperature is room temperature.

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