Method for removing organic matters in bauxite
Through the method of combining ball milling and adsorbent, organic matter is removed from the source in bauxite, solving the problem of difficulty in removing organic matter before dissolution at high temperature, achieving efficient and low-energy-consuming organic matter removal, ensuring the stability and efficiency of alumina production.
Patent Information
- Application Number
- CN202510713327.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-08-08
AI Technical Summary
The prior art is difficult to effectively remove organic matter before bauxite enters high temperature dissolution, resulting in problems such as increased solution viscosity, increased foam, increased alkaline consumption and poor red mud settlement performance during the alumina production process.
By ball milling the crushed bauxite and alkali liquid, solid-liquid separation is carried out after the organic matter removal reaction is performed, and adsorbent is added to the organic matter leaching liquid for adsorption and removal. Finally, the organic matter alkali liquid is circulated for ball milling to form a closed loop cycle.
It realizes the removal of organic matter from the source before bauxite enters high temperature dissolution, improves the removal rate, prevents organic matter from entering the Bayer method system, ensures the stability of alumina production, and reduces energy consumption.
Smart Images
Figure CN120440919A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of alumina production, and in particular to a method for removing organic matter from bauxite. Background Art
[0002] Bauxite from different sources and types inevitably contains organic impurities. During the Bayer process for alumina production, humic acid-based organic matter in the bauxite undergoes a series of oxidation and degradation processes under high temperature, high pressure, and strong alkaline conditions, gradually decomposing high-molecular-weight organic matter into low-molecular-weight organic matter. Ultimately, it is converted into small-molecule sodium salts such as acetates, oxalates, and carbonates, which accumulate continuously in the sodium aluminate solution. When this accumulation reaches a certain level, it can significantly impact alumina production, causing changes in the physical properties of the sodium aluminate solution, increasing its viscosity, increasing foaming in various solution storage tanks, increasing alkali consumption, deteriorating red mud settling performance, reducing decomposition rates, and impacting alumina product quality. Therefore, the removal of organic matter from bauxite and sodium aluminate solution is essential.
[0003] Oxidative roasting of bauxite can remove organic matter at the source, but pyrolysis roasting has high energy consumption, high carbon emissions, and a low organic matter removal rate, making it not yet commercially applicable. Organic matter removal is currently commonly performed during the alumina production process, with methods primarily including wet oxidation, crystallization removal, chemical precipitation, and physical adsorption. The wet oxidation method involves introducing oxidizing gases such as oxygen into the Bayer process to promote the oxidative decomposition of large organic molecules. However, this technology can significantly increase the carbon, alkali, and oxalate content in the system, necessitating the use of both carbon, alkali, and oxalate removal systems. Sodium oxalate crystallization removal is a common removal method, but its removal rate is low and it is suitable for bauxite with low organic carbon content. Bauxite with an organic carbon content greater than 0.3% cannot currently be directly used in Bayer process production. Summary of the Invention
[0004] The present application provides a method for removing organic matter from bauxite to solve the following technical problems: how to remove organic matter from bauxite at the source before entering high-temperature dissolution and improve the removal rate of organic matter in bauxite.
[0005] The present invention provides a method for removing organic matter from bauxite, the method comprising:
[0006] The crushed bauxite is ball-milled with alkali solution to obtain a raw ore slurry containing bauxite of a set particle size;
[0007] Under the conditions of a set reaction temperature and a set reaction time, the raw ore pulp is subjected to an organic matter removal reaction, and then solid-liquid separation is performed to obtain organic-free bauxite and an organic matter leachate;
[0008] adding an adsorbent to the organic leachate at a set temperature to adsorb and remove organic matter from the organic leachate to obtain a mixed slurry;
[0009] performing solid-liquid separation on the mixed slurry to obtain an organic-free alkali solution; and
[0010] The organic matter-free alkali solution is recycled for ball milling with bauxite to form a closed-loop cycle.
[0011] Optionally, the alkali solution Na2O K Concentration ≥40g / L.
[0012] Optionally, the set particle size is such that the bauxite particle size of +850 μm accounts for ≤1% and the bauxite particle size of +250 μm accounts for ≤50%.
[0013] Optionally, the organic carbon content of the bauxite is greater than 0.3%.
[0014] Optionally, the reaction temperature is set to 60° C. to 120° C., and the reaction time is set to 2 h to 12 h.
[0015] Optionally, the solid content of the raw ore slurry is 200g / L to 1000g / L.
[0016] Optionally, the temperature of the adsorption removal is 40° C. to 50° C., and the time of the adsorption removal is 1 h to 24 h.
[0017] Optionally, based on 1L of organic leachate, the added amount of the adsorbent is 5g / L to 15g / L.
[0018] Optionally, the adsorbent includes: one or a combination of fly ash and activated carbon.
[0019] Optionally, the organic carbon content of the organic-removed bauxite is ≤0.15%, and the organic removal rate is >60%.
[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0021] The embodiment of the present application provides a method for removing organic matter from bauxite, which includes: ball milling the crushed bauxite with alkali solution to obtain a raw ore slurry containing bauxite of a set particle size; subjecting the raw ore slurry to an organic matter removal reaction under the conditions of a set reaction temperature and a set reaction time, and then performing solid-liquid separation to obtain organic-free bauxite and an organic leachate; adding an adsorbent to the organic leachate with a set temperature to perform adsorption removal of organic matter in the organic leachate to obtain a mixed slurry; subjecting the mixed slurry to solid-liquid separation to obtain an organic-free alkali solution; and recycling the organic-free alkali solution for ball milling with bauxite to form a closed loop. Before the bauxite enters the high-temperature dissolution process, organic matter such as humic acid and oxalic acid is directly removed through a wet process to avoid problems such as organic matter entering the Bayer process system causing scarring and reduced decomposition rate, thereby ensuring the stability of alumina production. At the same time, the alkali solution destroys the molecular structure of the organic matter, and combined with ball milling refinement, increases the contact area and improves the removal efficiency. Thereby, the organic matter in the bauxite can be removed at the source before entering the high-temperature dissolution, and the removal rate of the organic matter in the bauxite can be improved. 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0024] Figure 1 A schematic flow chart of a method for removing organic matter from bauxite provided in an embodiment of the present application. DETAILED DESCRIPTION
[0025] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.
[0026] 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 hard 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 numbers within the range. For example, the description of a range 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 applies 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.
[0027] In addition, in the description of the specification of this application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely 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" refers to one or more, and "plurality" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple. "Parts" such as parts by weight and parts by mass represent 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, if 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 to 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.
[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0029] Figure 1 A schematic flow chart of a method for removing organic matter from bauxite provided in an embodiment of the present application.
[0030] like Figure 1 As shown, the present application provides a method for removing organic matter from bauxite, the method comprising:
[0031] S1. ball milling the crushed bauxite with alkali solution to obtain a raw ore slurry containing bauxite of a set particle size;
[0032] By ball milling, the bauxite particles are refined, the chemical reaction between the alkali solution and the organic matter is promoted, and the organic matter such as humic acid and oxalic acid is dissolved into the liquid phase, while meeting the particle size requirements of the subsequent bauxite dissolution.
[0033] In some embodiments, the set particle size is such that the bauxite particle size of +850 μm accounts for ≤1% and the bauxite particle size of +250 μm accounts for ≤50%.
[0034] It should be noted that in the mineral processing industry, “+” is used to mean “greater than” or “at least”. For example, a particle size of +850 μm usually means that the particle size of the particles is greater than 850 μm.
[0035] The finer the slurry particle size, the more conducive it is to the removal of organic matter. The bauxite particle size is limited (+850μm≤1%, +250μm≤50%), so as to increase the contact area between the mineral and the alkali solution and accelerate the reaction rate. At the same time, it avoids excessively fine particles that make subsequent liquid-solid separation difficult. In addition, the slurry particle size required for alumina production is basically +850μm≤1%, so that alumina production can be carried out directly after the organic matter is removed. For example, the proportion of bauxite with a particle size of +850μm can be 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1%, etc., and the proportion of bauxite with a particle size of +250μm can be 25%, 30%, 35%, 40%, 45%, 50%, etc.
[0036] In some embodiments, the bauxite has an organic carbon content of >0.3%.
[0037] In some embodiments, the Na2O K Concentration ≥40g / L.
[0038] Alkali solution can react with humic acid organic matter in bauxite, and high alkali concentration can promote the reaction. K Concentration ≥ 40g / L, high alkali concentration can destroy the molecular structure of organic matter (such as carboxylic acid groups react with alkali to form soluble salts), and the organic matter removal effect can meet the requirements. At the same time, the solubility of organic salts such as sodium oxalate is improved under strong alkaline conditions, reducing the residual organic matter in the slurry. For example, the Na2O KThe concentration can be 40g / L, 41g / L, 43g / L, 45g / L, 47g / L, 49g / L, 50g / L, 52g / L, etc.
[0039] In some embodiments, the solid content of the raw ore slurry is 200 g / L to 1000 g / L.
[0040] A slurry solids content below 200 g / L results in wasted alkali solution, low reaction efficiency, and reduced organic matter removal efficiency. A slurry solids content above 1000 g / L results in excessively high slurry concentration, increasing pumping energy consumption and the risk of uneven mixing. For example, the solids content of the raw slurry can be 200 g / L, 300 g / L, 500 g / L, 600 g / L, 800 g / L, 900 g / L, 1000 g / L, etc.
[0041] S2. Under the conditions of a set reaction temperature and a set reaction time, subjecting the raw ore slurry to an organic matter removal reaction, and then performing solid-liquid separation to obtain organic matter-free bauxite and an organic matter leachate;
[0042] The organic matter removal reaction involves subjecting ground bauxite to an alkali solution under certain temperature conditions, allowing the organic matter in the ore to react with the alkali solution and enter the alkali solution, thereby removing the organic matter from the ore. In actual production, the organic matter removal reaction occurs in a system that can meet the reaction temperature and reaction time, such as a reactor, using pipes and tanks. Simultaneously, solid-liquid separation is used to initially separate the organic-free bauxite (solid phase) from the organic-containing alkali solution (liquid phase) to prevent the organic matter from re-adsorbing onto the mineral surface.
[0043] In some embodiments, the set reaction temperature is 60° C. to 120° C., and the set reaction time is 2 h to 12 h.
[0044] It should be noted that the reaction temperature is set at 60°C to 120°C, that is, the temperature of the organic matter removal reaction is 60°C to 120°C; the reaction time is set at 2h to 12h, that is, the time of the organic matter removal reaction is 2h to 12h.
[0045] Increasing the organic matter removal temperature is beneficial to the removal of organic matter, but a temperature too high above 120°C will increase energy consumption. The time for organic matter removal is limited to 2 hours to 12 hours, which is conducive to the sufficient removal of organic matter. If the time is less than 2 hours, the organic matter removal effect is not good. If the time is longer than 12 hours, the organic matter removal effect will not continue to improve. For example, the temperature of the organic matter removal reaction can be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, etc., and the time of the organic matter removal reaction can be 2 hours, 3 hours, 5 hours, 7 hours, 9 hours, 11 hours, 12 hours, etc.
[0046] S3, adding an adsorbent to the organic leachate at a set temperature to adsorb and remove organic matter in the organic leachate to obtain a mixed slurry;
[0047] The organic matter in the liquid phase (especially sodium oxalate) is selectively adsorbed by the adsorbent to reduce the organic matter content in the alkali solution.
[0048] In some embodiments, the temperature of the adsorption removal is 40° C. to 50° C., and the time of the adsorption removal is 1 hour to 24 hours.
[0049] The equilibrium concentration of sodium oxalate in the alkali solution decreases with decreasing temperature. Lowering the temperature facilitates the crystallization of sodium oxalate. Experiments have shown that cooling to 40°C to 50°C results in a higher sodium oxalate removal efficiency. If the adsorption removal temperature is <40°C, the viscosity of the eluate increases, hindering subsequent liquid-solid separation. If the adsorption removal temperature is >50°C, the sodium oxalate removal efficiency decreases. An adsorption removal time of 1 to 24 hours indicates that the adsorbent remains in the organic leachate for 1 to 24 hours, thereby facilitating sufficient adsorption of the organic matter. For example, the adsorption removal temperature can be 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc., and the adsorption removal time can be 1 hour, 5 hours, 10 hours, 15 hours, 20 hours, 24 hours, etc.
[0050] In some embodiments, the amount of the adsorbent added is 5 g / L to 15 g / L based on 1 L of organic leachate.
[0051] The concentration of sodium oxalate in the alkali solution is typically less than 5 g / L. Adding a small amount of adsorbent can achieve good adsorption removal. Adding too much increases costs and hinders subsequent liquid-solid separation. Experimental results recommend a range of 5 g / L to 15 g / L. For example, the adsorbent addition amount can be 5 g / L, 7 g / L, 9 g / L, 11 g / L, 13 g / L, 15 g / L, etc.
[0052] In some embodiments, the adsorbent includes: fly ash and activated carbon, or a combination of both.
[0053] Adsorbents such as fly ash and activated carbon are materials with many pores and large surface areas, which can adsorb large molecular organic matter and sodium oxalate in alkali solution to remove organic matter. Fly ash is rich in porous aluminosilicates and has a specific surface area of 200m 2 / g~400m 2 / g, preferentially adsorbing large molecular humic acid (adsorption capacity of about 50mg / g). The microporous structure of activated carbon is well developed (specific surface area 800~1200m 2 / g), and its adsorption capacity for sodium oxalate is 80mg / g~120mg / g.
[0054] S4, performing solid-liquid separation on the mixed slurry to obtain an organic-free alkali solution;
[0055] Through solid-liquid separation, the adsorbent and the purified alkali solution can be separated.
[0056] In some embodiments, the fly ash can be regenerated by high temperature calcination (600° C.), and the activated carbon can be acid washed (pH=2) to restore its adsorption capacity.
[0057] S5. The organic-free alkali solution is recycled for ball milling with bauxite to form a closed-loop cycle.
[0058] By circulating the organic-free alkali solution, a closed-loop system can be formed, which reduces the consumption of fresh alkali solution and lowers the cost of wastewater treatment.
[0059] In some embodiments, the organic carbon content of the deorganized bauxite is ≤0.15%, and the organic matter removal rate is >60%.
[0060] Compared to existing technologies, the present invention provides a method for removing organic matter from bauxite, enabling the removal of organic matter from the bauxite at the source before high-temperature dissolution, thereby preventing it from entering the Bayer process and impacting production. This method is a fully wet process with low energy consumption and the advantages of easy integration with Bayer process production. Exemplary organic matter removal rates can be 61%, 63%, 65%, 67%, 70%, 75%, and the like.
[0061] In summary, the method for removing organic matter from bauxite provided in the embodiments of the present application has the following advantages:
[0062] (1) Remove organic matter at the source to avoid system pollution: Before the bauxite enters the high-temperature dissolution process, humic acid, oxalic acid and other organic matter are directly removed through a wet process (organic carbon removal rate > 60%, final content ≤ 0.15%) to prevent organic matter from entering the Bayer process system, causing problems such as scarring and reduced decomposition rate, thereby ensuring the stability of alumina production.
[0063] (2) Fully wet process, low energy consumption and strong compatibility: The entire process adopts wet processing (ball milling, adsorption, solid-liquid separation), without the need for high-temperature calcination or complex equipment. The process has low energy consumption and can be directly grafted with the existing Bayer process production line without the need for large-scale transformation.
[0064] (3) Efficient removal and recycling of alkali solution: alkali solution Destroy the molecular structure of organic matter, combined with ball milling refinement (+850μm ≤ 1%, +250μm ≤ 50%), increase the contact area, and improve removal efficiency. At the same time, a combination of fly ash (adsorbing humic acid) and activated carbon (adsorbing sodium oxalate) can be used to remove different organic matter in a targeted manner. The adsorption capacity is high (fly ash 50mg / g, activated carbon 80-120mg / g), and the adsorbent is regenerable (fly ash calcination, activated carbon pickling), reducing operating costs. In addition, the removed alkali solution is reused in the ball milling process, reducing the consumption of fresh alkali solution (recycling rate > 90%) and reducing the burden of waste liquid treatment.
[0065] (4) Parameter optimization, balancing efficiency and cost: Parameters such as removal temperature (60-120°C), time (2-12h), and slurry solid content (200-1000g / L) have been optimized to balance removal efficiency and energy consumption. At the same time, the adsorption temperature (40-50°C) and time (1-24h) match the solubility characteristics of sodium oxalate, and the adsorbent dosage is low (5-15g / L), avoiding resource waste. It has strong adaptability and is suitable for high-organic carbon ores. It can process high-organic bauxite with an organic carbon content of >0.3%, broadening the scope of low-grade mineral resource utilization and improving resource utilization.
[0066] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are generally measured according to industry standards. If there are no corresponding industry standards, then the methods are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.
[0067] Example 1
[0068] This embodiment provides a method for removing organic matter from bauxite, comprising the following steps:
[0069] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 40g / L, the grinding particle size is +850μm≤1%, +250μm≈25%
[0070] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 100°C, the reaction time is 8 hours, and the solid content of the ore pulp is 400g / L.
[0071] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.14%, and it can be directly subjected to Bayer dissolution;
[0072] Sd: The organic matter leachate is cooled to 40°C and fly ash is added to absorb the organic matter. The addition amount is 10 g / L and the residence time is 10 h.
[0073] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0074] Example 2
[0075] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 100g / L, the grinding particle size is +850μm≤1%, +250μm≈25%
[0076] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 105°C, the reaction time is 10 hours, and the solid content of the ore pulp is 600g / L.
[0077] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.12%, and it can be directly subjected to Bayer dissolution;
[0078] Sd: The organic matter leachate is cooled to 40°C and fly ash is added to absorb the organic matter. The addition amount is 10 g / L and the residence time is 10 h.
[0079] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0080] Example 3
[0081] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 100g / L, the grinding particle size is +850μm≤1%, +250μm≈40%
[0082] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 60°C, the reaction time is 12 hours, and the solid content of the ore pulp is 400g / L.
[0083] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.15%, and it can be directly subjected to Bayer process dissolution;
[0084] Sd: The organic matter leachate is cooled to 45°C and fly ash is added to absorb the organic matter. The addition amount is 15g / L and the residence time is 5h.
[0085] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0086] Example 4
[0087] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 150g / L, the grinding particle size is +850μm≤1%, +250μm≈40%
[0088] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 120°C, the reaction time is 6 hours, and the solid content of the ore pulp is 600g / L.
[0089] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.11%, and it can be directly subjected to Bayer process dissolution;
[0090] Sd: The organic matter leachate is cooled to 40°C and fly ash is added to absorb the organic matter. The addition amount is 15g / L and the residence time is 5h.
[0091] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0092] Example 5
[0093] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 200g / L, the grinding particle size is +850μm≤1%, +250μm≈40%
[0094] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 110°C, the reaction time is 6 hours, and the solid content of the ore pulp is 600g / L.
[0095] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.11%, and it can be directly subjected to Bayer process dissolution;
[0096] Sd: The organic matter leachate is cooled to 40°C and fly ash is added to absorb the organic matter. The addition amount is 15g / L and the residence time is 24h.
[0097] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0098] Example 6
[0099] Sa: Using imported bauxite as raw material, its organic carbon content is 0.4%. The bauxite is crushed and ball milled with alkali solution to prepare raw ore slurry. The alkali solution Na2O k The concentration is 200g / L, the grinding particle size is +850μm≤1%, +250μm≈40%
[0100] Sb: Add the prepared raw ore pulp into the reactor to remove organic matter from the bauxite. The reactor temperature is controlled at 110°C, the reaction time is 12 hours, and the solid content of the ore pulp is 800g / L.
[0101] Sc: After the organic matter is removed, the slurry is subjected to solid-liquid separation to obtain organic-free bauxite and organic leachate. The organic carbon content of the organic-free bauxite is reduced to 0.12%, and it can be directly subjected to Bayer dissolution;
[0102] Sd: The organic matter leachate is cooled to 40°C and fly ash is added to absorb the organic matter. The addition amount is 15g / L and the residence time is 15h.
[0103] Se: The adsorbent and the leachate are separated into solid and liquid to obtain an organic-free alkali solution, which is then returned to prepare the original ore pulp.
[0104] The organic carbon content of the bauxite raw material, the organic carbon content of the deorganized bauxite and the organic matter removal rate in Examples 1 to 6 are summarized, and the results are shown in Table 1.
[0105] Table 1 Organic carbon content and organic matter removal rate of bauxite raw materials and deorganized bauxite in Examples 1 to 6
[0106]
[0107] As can be seen from Table 1, the organic carbon content of the organic-removed bauxite in Examples 1 to 6 is ≤0.15%, and the organic matter removal rate is >60%.
[0108] In addition, one or more technical solutions in the embodiments of the present application have at least the following technical effects or advantages:
[0109] In the embodiment of the present application, the organic matter in the bauxite can be removed at the source before entering the high-temperature dissolution, thereby avoiding entering the Bayer process system and affecting production. At the same time, this method is a fully wet process, which has the advantages of low energy consumption and easy integration with Bayer process production.
[0110] The method for removing organic matter from bauxite provided in the embodiments of the present application can be applied to all bauxites with high organic carbon content.
[0111] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.
Claims
1. A method for removing organic matter from bauxite, the method comprising: The crushed bauxite is ball-milled with alkali solution to obtain a raw ore slurry containing bauxite of a set particle size; Under the conditions of a set reaction temperature and a set reaction time, the raw ore pulp is subjected to an organic matter removal reaction, and then solid-liquid separation is performed to obtain organic-free bauxite and an organic matter leachate; adding an adsorbent to the organic leachate at a set temperature to adsorb and remove organic matter from the organic leachate to obtain a mixed slurry; performing solid-liquid separation on the mixed slurry to obtain an organic-free alkali solution; and The organic matter-free alkali solution is recycled for ball milling with bauxite to form a closed-loop cycle.
2. The method according to claim 1, characterized in that The Na2O of the alkali solution K Concentration ≥40g / L.
3. The method according to claim 1, characterized in that The set particle size is such that the bauxite particle size of +850 μm accounts for ≤1%, and the bauxite particle size of +250 μm accounts for ≤50%.
4. The method according to claim 1, wherein The organic carbon content of the bauxite is greater than 0.3%.
5. The method according to claim 1, wherein The reaction temperature is set to 60° C. to 120° C., and the reaction time is set to 2 h to 12 h.
6. The method according to claim 1, characterized in that The solid content of the raw ore slurry is 200g / L to 1000g / L.
7. The method according to claim 1, characterized in that The temperature of the adsorption removal is 40° C. to 50° C., and the time of the adsorption removal is 1 hour to 24 hours.
8. The method according to claim 1, characterized in that Based on 1L of organic leachate, the added amount of the adsorbent is 5g / L to 15g / L.
9. The method according to claim 8, characterized in that The adsorbent includes: fly ash and activated carbon or a combination of the two.
10. The method according to claim 1, characterized in that The organic carbon content of the organic-removed bauxite is less than or equal to 0.15%, and the organic matter removal rate is greater than 60%.