Improved method for recycling red mud

Abstract

The invention relates to the technical field of red mud waste recycling, in particular to an improved red mud recycling method. The method comprises the following steps: carrying out dissolution reaction on red mud, alkali liquor and degassed carbide slag to obtain a dissolved substance; carrying out solid-liquid separation on the dissolved substance to respectively obtain a liquid product and solid waste; the liquid product is used for alumina production circulating mother liquor; the solid waste comprises molten garnet. According to the method, the mass concentration and the weight of the caustic alkali in the alkali liquor and the addition amount of the degassed carbide slag are adjusted according to different iron oxide contents in the red mud, so that sodium resources and aluminum resources in the red mud can be effectively recovered on the premise of fully considering the iron oxide contents in the red mud, and the recovery rates of the sodium resources and the aluminum resources in the red mud are improved; meanwhile, the degassed carbide slag is consumed as much as possible, so that the content of sodium oxide in the final solid waste can be reduced to be within 1%, and a foundation is laid for comprehensive utilization of the solid waste.

Description

Technical Field

[0001] The present application relates to the technical field of red mud waste recycling and utilization, and in particular to an improved method for recycling and treating red mud. Background Art

[0002] At present, the main method of alumina production is the Bayer process, but the Bayer process produces 1 to 2 tons of red mud for every ton of alumina produced. However, the alkali content of red mud is high, which will have an adverse effect on the environment. In addition, in addition to the large alkali content, Bayer red mud also contains a large amount of aluminum oxide, silicon dioxide and other substances; in order to recover the sodium and aluminum resources in the Bayer red mud at this stage, the method of adding lime can be adopted, but lime needs to be obtained by roasting limestone, which will not only consume a lot of energy but also consume natural mineral resources. Calcium carbide slag is the waste residue produced by the hydrolysis of calcium carbide in the process of industrial production of acetylene gas, polyvinyl chloride (PVC) or polyvinyl alcohol (PVA), and its main component is calcium hydroxide; at present, calcium carbide slag cannot be properly handled and can only be directly piled up in the open air, which undoubtedly occupies a lot of land and pollutes the surrounding soil and water sources during the stacking process.

[0003] Although degassed carbide slag can be used to replace part of the lime at this stage, it can solve the problem of carbide slag and red mud stacking and effectively recover the sodium and aluminum resources in the red mud; however, there will be a large amount of iron oxide in some red mud, and the presence of iron oxide has a great impact on the recovery of sodium and aluminum resources, and will also consume more degassed carbide slag. At this stage, when degassed carbide slag is used to replace lime for treatment, the influence of iron oxide in red mud is not taken into account, resulting in a low recovery rate of sodium and aluminum resources in red mud, and the poorer degassed carbide slag cannot be used more.

[0004] At present, the method of using deaerated carbide slag to replace lime to recover sodium and aluminum resources in red mud includes: K The method comprises the following steps: mixing 60g / L to 280g / L alkali solution with red mud in a manner of mixing 50g to 350g of red mud per liter of alkali solution to obtain a mixture; dissolving degassed carbide slag (the content of CaO component in the degassed carbide slag is more than 52% of the dry weight of the degassed carbide slag, and the content of organic carbon in the degassed carbide slag is less than 0.5%) in a manner that the weight of the degassed carbide slag accounts for 10% to 35% of the weight of the red mud; setting the dissolution treatment temperature to 240°C to 280°C and the dissolution treatment time to 60min to 120min to obtain solid waste; and the A / S of the solid waste obtained is 0.62 to 0.88, and the N / S is 0.08 to 0.2; in addition, the recovery rate of sodium resources of the overall method can reach 55% to 80% in terms of sodium oxide, and the recovery rate of aluminum resources of the overall method can reach 48% to 55% in terms of aluminum oxide. Summary of the invention

[0005] The present application provides an improved method for recycling and treating red mud to solve the following technical problem: how to increase the usage of degassed carbide slag while improving the recovery rate of sodium and aluminum resources in the process of treating red mud with degassed carbide slag.

[0006] In a first aspect, the present application provides an improved method for recycling red mud, wherein the red mud contains iron oxide and sodium silicate slag, and the weight content of the iron oxide is greater than or equal to 6% of the total weight of the red mud, and the method comprises:

[0007] The red mud, alkali solution and degassed carbide slag are subjected to a dissolution reaction to obtain a dissolution product;

[0008] Performing solid-liquid separation on the dissolution to obtain a liquid product and solid waste respectively;

[0009] Wherein, the liquid product is used as circulating mother liquor for alumina production; the solid waste includes ferrohydrite garnet;

[0010] The weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the weight of the degassed carbide slag are adjusted according to the weight content of the iron oxide.

[0011] Optionally, when the weight content of iron oxide is greater than or equal to 6% and less than or equal to 11% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(80~180):(60~400), the mass concentration of caustic soda in the alkali solution is 80g / L~180g / L, and the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.10~0.40):1.

[0012] Optionally, the degassed carbide slag includes calcium oxide and organic carbon, and the weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.52:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.005:1.

[0013] Optionally, when the weight content of iron oxide is greater than 11% and less than or equal to 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100~240):(80~450), the mass concentration of caustic soda in the alkali solution is 100g / L~240g / L, and the weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15~0.45):1.

[0014] Optionally, the degassed carbide slag includes calcium oxide and organic carbon, the weight m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:1.

[0015] Optionally, when the weight content of iron oxide is greater than 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100~280):(100~500), the mass concentration of caustic soda in the alkali solution is 100g / L~280g / L, and the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15~0.50):1.

[0016] Optionally, the degassed carbide slag includes calcium oxide and organic carbon, and the weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:1.

[0017] Optionally, the temperature of the dissolution reaction is 240° C. to 280° C., and the time of the dissolution reaction is 30 min to 120 min.

[0018] Optionally, the yield of sodium oxide in the sodium silicon slag is positively correlated with the weight content of the iron oxide; the yield of aluminum oxide in the red mud is positively correlated with the weight content of the iron oxide. The above technical solution provided in the embodiment of the present application has the following advantages over the prior art:

[0019] An improved method for recycling and treating red mud is provided in an embodiment of the present application, wherein the red mud contains iron oxide and sodium silicate slag, and the weight content of the iron oxide is greater than or equal to 6% of the total weight of the red mud. The red mud contains iron oxide and sodium silicate slag, and the method comprises: subjecting red mud, alkali solution, and degassed carbide slag to a dissolution reaction to obtain a dissolution product; performing solid-liquid separation on the dissolution product to obtain a liquid product and solid waste, respectively; wherein the liquid product is used as a circulating mother liquor for alumina production; the solid waste comprises ferrohydrated garnet; the weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution, and the total weight of the degassed carbide slag are respectively adjusted according to the weight content of the iron oxide. The weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the total weight of degassed carbide slag can be adjusted according to the weight content of iron oxide, respectively. For red mud with different iron oxide contents, adding alkali solution with corresponding mass concentration of caustic soda, alkali solution with corresponding weight content of caustic soda and degassed carbide slag in corresponding amount can promote the full reaction between the iron oxide and sodium silicate slag [Na2O·Al2O3·nSiO2·(6-2n)H2O] in the red mud and calcium hydroxide in the degassed carbide slag, so as to better generate a new mineral iron hydrate garnet [3CaO·Al2O3(Fe 2O3)nSiO2·2H2O] solid waste, thereby realizing the recovery of sodium oxide component and aluminum oxide component of sodium silicate slag in red mud. In addition, this method clarifies the influence of relevant raw materials on the generation process of solid waste with ferrohydrate garnet, and can clarify the most favorable conditions for the generation of ferrohydrate garnet from iron oxide and sodium silicate slag in red mud and calcium hydroxide in degassed carbide slag, so as to fully recover the aluminum resources and sodium resources in red mud and the calcium hydroxide resources in degassed carbide slag, so as to increase the use of degassed carbide slag while improving the recovery rate of sodium resources and aluminum resources in the process of degassed carbide slag treatment of red mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic flow chart of an improved method for recycling and treating red mud provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has 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 in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0025] In this document, the terms "including" and "comprising" mean "including but not limited to". Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0026] It should be noted that, with respect to the method recorded in the prior art in the background technology of using degassed carbide slag instead of lime to recover sodium and aluminum resources in red mud, the inventors found that the presence of iron oxide in red mud will replace the aluminum oxide in red mud and enhance the reaction of calcium oxide in degassed carbide slag replacing sodium oxide, thereby improving the recovery of sodium and aluminum resources in red mud and increasing the use of degassed carbide slag.

[0027] Figure 1 The schematic diagram of a process flow of an improved method for recycling and treating red mud provided in an embodiment of the present application is exemplarily shown;

[0028] like Figure 1 As shown, the embodiment of the present application provides an improved method for recycling and treating red mud, wherein the red mud contains iron oxide, aluminum oxide and sodium silicate slag, and the weight content of the iron oxide is greater than or equal to 6% of the total weight of the red mud. The method comprises:

[0029] S1. The red mud, alkali solution, and degassed carbide slag are subjected to a dissolution reaction to obtain a dissolution product;

[0030] S2. performing solid-liquid separation on the dissolution to obtain a liquid product and a solid waste, respectively;

[0031] Wherein, the liquid product is used as circulating mother liquor for alumina production; the solid waste includes ferrohydrite garnet;

[0032] The weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the weight of the degassed carbide slag are adjusted according to the weight content of the iron oxide.

[0033] It should be noted that the weight content of iron oxide in red mud can affect the degree of reaction between calcium hydroxide in degassed carbide slag and sodium silicate slag in red mud to form ferrohydrite garnet, thereby affecting the recovery of sodium and aluminum resources in red mud and also changing the amount of degassed carbide slag used.

[0034] In some optional embodiments, when the weight content of the iron oxide is greater than or equal to 6% and less than or equal to 11% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(80-180):(60-400), the mass concentration of the caustic soda in the alkali solution is 80g / L-180g / L, and the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.10-0.40):1;

[0035] In these embodiments, when the weight content of iron oxide can be greater than or equal to 6% and less than or equal to 11% of the total weight of red mud, the weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud can satisfy the relationship: m2:m1=(80-180):(60-400), and the mass concentration of caustic soda in the alkali solution can be 80 g / L-180 g / L, and the weight m3 of degassed carbide slag and the total weight m1 of red mud can satisfy the relationship: m3:m1=(0.10-0.40):1, the amount of caustic soda used in the alkali solution and the corresponding mass concentration N can be adjusted according to the high level of iron oxide content in the red mud. K and the weight of degassed carbide slag added to the red mud, so that the iron oxide and sodium silicate slag in the red mud can be prompted to fully react with the calcium hydroxide in the degassed carbide slag to form ferrohydrate garnet 3CaO·Al2O3(Fe2O3)nSiO2·2H2O, so as to improve the recovery rate of sodium and aluminum resources in the red mud; at this time, the iron oxide content in the red mud is at a medium-low level, the A / S of the solid waste can reach 0.62-0.78, and the N / S is 0.08-0.20. For red mud with an A / S of 1.5 and an N / S of 0.4, it can be deduced based on the solid waste that the recovery rate of aluminum oxide is 48%-58.7%, and the recovery rate of sodium oxide is 50%-80%.

[0036] The weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud can satisfy the relationship: m2:m1=80:60, 80:100, 80:200, 80:300, 80:400, 100:60, 100:100, 100:200, 100:300, 100:400, 120:60, 120:100, 120:200, 1 or 180:400.

[0037] The mass concentration of caustic soda in the alkali solution can be 80 g / L, 100 g / L, 120 g / L, 140 g / L, 160 g / L or 180 g / L.

[0038] The weight m3 of the degassed carbide slag and the total weight m1 of the red mud can satisfy the relationship: m3:m1=0.10:1, 0.20:1, 0.30:1 or 0.40:1.

[0039] In some optional embodiments, the degassed carbide slag includes calcium oxide and organic carbon, and the weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.52:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.005:1. In these embodiments, the degassed carbide slag may include calcium oxide and organic carbon, and the weight m4 of the calcium oxide and the weight m3 of the degassed carbide slag may be To satisfy the relationship: m4:m3>0.52:1, and the weight of organic carbon m5 and the weight of degassed carbide slag m3 can satisfy the relationship: m5:m3<0.005:1. The contents of calcium oxide and organic carbon in the degassed carbide slag are adjusted according to the iron oxide level in the red mud. This can ensure that there is a sufficient amount of calcium oxide and a small amount of organic carbon in the degassed carbide slag, so that the sodium and aluminum resources in the red mud can be effectively recovered through the degassed carbide slag, thereby improving the recovery rate of sodium and aluminum resources in the red mud.

[0040] In some optional embodiments, when the weight content of iron oxide is greater than 11% and less than or equal to 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100-240):(80-450), the mass concentration of the caustic soda in the alkali solution is 100g / L-240g / L, and the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15-0.45):1.

[0041] In these embodiments, when the weight content of iron oxide is greater than 11% and less than or equal to 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud may satisfy the relationship:

[0042] m2:m1=(100-240):(80-450), and the mass concentration of caustic soda in the alkali solution can be 100g / L-240g / L, and the total weight of degassed carbide slag m3 and the total weight of red mud m1 can satisfy the relationship: m3:m1=(0.15-0.45):1, and the amount of alkali solution used and the corresponding mass concentration N can be adjusted according to the higher level of iron oxide content in the red mud. K and the amount of degassed carbide slag added, so that the iron oxide and sodium silicate slag in the red mud can be fully reacted with the calcium hydroxide in the degassed carbide slag to form ferrohydrate garnet 3CaO·Al2O3(Fe2O3)nSiO2·2H2O, so as to improve the recovery rate of sodium resources and aluminum resources in the red mud. At this time, the iron oxide content in the red mud is at a medium-high level, the A / S of the solid waste can reach 0.52-0.72, the N / S is only 0.01-0.10, and the sodium oxide content is less than 1%. For red mud with an A / S of 1.5 and an N / S of 0.4, it can be deduced based on the solid waste that the recovery rate of aluminum oxide is 52.0%-65.3%, and the recovery rate of sodium oxide is 75.00%-99.75%.

[0043] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud can satisfy the relationship: m2:m1=100:80, 100:100, 100:200, 100:300, 100:400, 100:450, 170:80, 170:100, 170:200, 170:300, 170:400, 170:450, 240:80, 240:100, 240:200, 240:300, 240:400 or 240:450.

[0044] The mass concentration of caustic soda in the alkali solution can be 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 220 g / L or 240 g / L.

[0045] The weight m3 of the degassed carbide slag and the total weight m1 of the red mud can satisfy the relationship: m3:m1=0.15:1, 0.20:1, 0.25:1, 0.30:1, 0.35:1, 0.40:1 or 0.45:1.

[0046] In some optional embodiments, the degassed carbide slag includes calcium oxide and organic carbon, the weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:1.

[0047] In these embodiments, degassed carbide slag may include calcium oxide and organic carbon, and the weight content m4 of calcium oxide and the weight m3 of degassed carbide slag may satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of organic carbon and the weight m3 of degassed carbide slag may satisfy the relationship: m5:m3<0.006:1. Adjusting the contents of calcium oxide and organic carbon in the degassed carbide slag according to the level of iron oxide in the red mud can promote the presence of sufficient calcium oxide components and a small amount of organic carbon components in the degassed carbide slag, so as to effectively recover sodium resources and aluminum resources in the red mud through the degassed carbide slag, thereby improving the recovery rate of sodium resources and aluminum resources in the red mud.

[0048] In some optional embodiments, when the weight content of iron oxide is greater than 29% of the total weight of red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100-280):(100-500), the mass concentration of the caustic soda in the alkali solution is 100g / L-280g / L, and the weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15-0.50):1;

[0049] In these embodiments, when the weight of iron oxide is greater than 29% of the total weight of red mud, the weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud can satisfy the relationship: m2:m1=(100-280):(100-500), and the mass concentration of caustic soda in the alkali solution can be 100 g / L-280 g / L, and the weight m3 of degassed carbide slag and the total weight m1 of red mud can satisfy the relationship: m3:m1=(0.15-0.50):1, and the amount of caustic soda used in the alkali solution and the corresponding mass concentration N can be adjusted for the high level of iron oxide content in the red mud.K and the amount of degassed carbide slag added, so that the iron oxide and sodium silicate slag in the red mud can be fully reacted with the calcium hydroxide in the degassed carbide slag to form ferrohydrate garnet 3CaO·Al2O3(Fe2O3)nSiO2·2H2O, so as to improve the recovery rate of sodium and aluminum resources in the red mud. At this time, the iron oxide content in the red mud is at a relatively high level, the A / S of the solid waste can reach 0.48-0.66, and the N / S is only 0.01-0.08. For red mud with an A / S of 1.5 and an N / S of 0.4, it can be deduced based on the solid waste that the recovery rate of aluminum oxide is 56%-68%, and the recovery rate of sodium oxide is 80%-99.75%.

[0050] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud can satisfy the relationship: m2:m1=100:100, 100:200, 100:300, 100:400, 100:500, 170:100, 170:200, 170:300, 170:400, 170:500, 240:100, 240:200, 240:300, 240:400 or 240:500.

[0051] The mass concentration of caustic soda in the alkali solution can be 100 g / L, 120 g / L, 140 g / L, 160 g / L, 180 g / L, 200 g / L, 220 g / L, 240 g / L, 260 g / L or 280 g / L.

[0052] The weight m3 of the degassed carbide slag and the total weight m1 of the red mud can satisfy the relationship: m3:m1=0.15:1, 0.20:1, 0.25:1, 0.30:1, 0.35:1, 0.40:1, 0.45:1 or 0.50:1.

[0053] In some optional embodiments, the degassed carbide slag includes calcium oxide and organic carbon, the weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:1.

[0054] In these embodiments, the degassed carbide slag may include calcium oxide and organic carbon, and the weight content m4 of calcium oxide and the weight m3 of the degassed carbide slag may satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of organic carbon and the weight m3 of the degassed carbide slag may satisfy the relationship: m5:m3<0.006:1. Adjusting the content of calcium oxide and organic carbon in the degassed carbide slag according to the level of iron oxide in the red mud may promote the presence of sufficient calcium oxide components and a small amount of organic carbon components in the degassed carbide slag, so as to effectively recover sodium resources and aluminum resources in the red mud through the degassed carbide slag, thereby improving the recovery rate of sodium resources and aluminum resources in the red mud. In some optional embodiments, the temperature of the dissolution reaction is 240°C to 280°C, and the time of the dissolution reaction is 30min to 120min.

[0055] In some optional embodiments, the yield of sodium oxide in the sodium silicate slag is positively correlated with the weight content of the iron oxide; the yield of aluminum oxide in the red mud is positively correlated with the weight content of the iron oxide;

[0056] In these embodiments, the yield of sodium oxide in sodium silicate slag can be positively correlated with the weight content of iron oxide, and the yield of aluminum oxide in red mud can be positively correlated with the weight content of iron oxide, which means that the yield of aluminum oxide in red mud and the yield of sodium oxide will be affected by the iron oxide in red mud. Therefore, through the method provided in the embodiments of the present application, the sodium oxide component and aluminum oxide component of sodium silicate slag in red mud can be recovered.

[0057] In some optional embodiments, the temperature of the dissolution reaction is 240°C to 280°C, and the time of the dissolution reaction is 30min to 120min;

[0058] In these embodiments, the temperature of the dissolution reaction can be 240°C to 280°C, and the time of the dissolution reaction can be 30min to 120min, which can promote the dissolution reaction to proceed fully, so as to promote the iron oxide and sodium silicate in the red mud to fully react with the calcium hydroxide in the degassed carbide slag to form ferrohydrite garnet 3CaO·Al2O3(Fe2O3)nSiO2·2H2O, so as to improve the recovery rate of sodium resources and aluminum resources in the red mud.

[0059] The temperature of the dissolution reaction may be 240°C, 250°C, 260°C, 270°C or 280°C.

[0060] The dissolution reaction time can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min.

[0061] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually measured according to industry standards; if there are no corresponding industry standards, they are carried out according to common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0062] Example 1

[0063] Red mud was weighed, and the weight content of iron oxide in the red mud was 8% of the total weight of the red mud, satisfying the condition that the weight content of iron oxide was greater than or equal to 6% and less than or equal to 11% of the total weight of the red mud. The A / S and N / S of the red mud were 1.5 and 0.4.

[0064] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.60:1>0.52:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.003:1<0.005:1.

[0065] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=100:280, the mass concentration of caustic soda in the alkali solution is 100g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:280g.

[0066] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.30:1.

[0067] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0068] Example 2

[0069] Based on the contents disclosed in Example 1, the following modifications are further made:

[0070] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=140:300, the mass concentration of caustic soda in the alkali solution is 140g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:300g.

[0071] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.25:1.

[0072] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0073] Example 3

[0074] Based on the contents disclosed in Example 1, the following modifications are further made:

[0075] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=160:340, the mass concentration of caustic soda in the alkali solution is 160g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:340g.

[0076] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.34:1.

[0077] The temperature of the dissolution reaction is 280°C, and the time of the dissolution reaction is 45 minutes.

[0078] Example 4

[0079] Based on the contents disclosed in Example 1, the following modifications are further made:

[0080] Red mud was weighed, and the weight content of iron oxide in the red mud was 14% of the total weight of the red mud, satisfying the condition that the weight content of iron oxide was greater than 11% and less than or equal to 29% of the total weight of the red mud. The A / S and N / S of the red mud were 1.5 and 0.4.

[0081] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.58:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.004:1<0.006:1.

[0082] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=120:250, the mass concentration of caustic soda in the alkali solution is 120g / L, and the added volume V1 of the alkali solution and the weight m1 of the red mud satisfy the relationship: V1:m1=1L:250g.

[0083] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.30:1.

[0084] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0085] Example 5

[0086] Based on the contents disclosed in Example 4, the following modifications are further made:

[0087] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=160:350, the mass concentration of caustic soda in the alkali solution is 160g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:350g.

[0088] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.30:1.

[0089] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0090] Example 6

[0091] Based on the contents disclosed in Example 4, the following modifications are further made:

[0092] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=200:380, the mass concentration of caustic soda in the alkali solution is 200g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:380g.

[0093] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.40:1.

[0094] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0095] Example 7

[0096] Based on the contents disclosed in Example 1, the following modifications are further made:

[0097] Red mud was weighed, and the weight content of iron oxide in the red mud was 22% of the total weight of the red mud, satisfying the condition that the weight content of iron oxide was greater than 11% and less than or equal to 29% of the total weight of the red mud. The A / S and N / S of the red mud were 1.5 and 0.4.

[0098] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.56:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.002:1<0.006:1.

[0099] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=140:250, the mass concentration of caustic soda in the alkali solution is 140g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:250g.

[0100] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.30:1.

[0101] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0102] Example 8

[0103] Based on the contents disclosed in Example 7, the following modifications are further made:

[0104] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=180:300, the mass concentration of caustic soda in the alkali solution is 180g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:300g.

[0105] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.35:1.

[0106] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0107] Example 9

[0108] Based on the contents disclosed in Example 7, the following modifications are further made:

[0109] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=220:350, the mass concentration of caustic soda in the alkali solution is 220g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:350g.

[0110] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.40:1.

[0111] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0112] Example 10

[0113] Based on the contents disclosed in Example 1, the following modifications are further made:

[0114] The red mud was weighed, and the weight content of iron oxide in the red mud was 31% of the total weight of the red mud, which was consistent with the situation that the weight content of iron oxide was greater than 29% of the total weight of the red mud. The A / S ratio of the red mud was 1.5 and the N / S ratio was 0.4.

[0115] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.54:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.002:1<0.006:1.

[0116] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=160:350, the mass concentration of caustic soda in the alkali solution is 160g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:350g.

[0117] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.35:1.

[0118] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0119] Embodiment 11

[0120] Based on the contents disclosed in Example 10, the following modifications are further made:

[0121] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=200:400, the mass concentration of caustic soda in the alkali solution is 200g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:400g.

[0122] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.45:1.

[0123] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0124] Example 12

[0125] Based on the contents disclosed in Example 10, the following modifications are further made:

[0126] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=240:380, the mass concentration of caustic soda in the alkali solution is 240g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:380g.

[0127] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.40:1.

[0128] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0129] Example 13

[0130] Based on the contents disclosed in Example 1, the following modifications are further made:

[0131] The red mud was weighed, and the weight content of iron oxide in the red mud was 34% of the total weight of the red mud, which was consistent with the situation that the weight content of iron oxide was greater than 29% of the total weight of the red mud. The A / S ratio of the red mud was 1.5 and the N / S ratio was 0.4.

[0132] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.52:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.002:1<0.006:1.

[0133] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=180:450, the mass concentration of caustic soda in the alkali solution is 180g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:450g.

[0134] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.45:1.

[0135] The temperature of the dissolution reaction is 270°C, and the time of the dissolution reaction is 60 minutes.

[0136] Embodiment 14

[0137] Based on the contents disclosed in Example 1, the following modifications are further made:

[0138] The red mud was weighed, and the weight content of iron oxide in the red mud was 34% of the total weight of the red mud, which was consistent with the situation that the weight content of iron oxide was greater than 29% of the total weight of the red mud. The A / S ratio of the red mud was 1.5 and the N / S ratio was 0.4.

[0139] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.50:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.004:1<0.006:1.

[0140] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=240:420, the mass concentration of caustic soda in the alkali solution is 240g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:420g.

[0141] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.45:1.

[0142] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0143] Embodiment 15

[0144] Based on the contents disclosed in Example 1, the following modifications are further made:

[0145] The red mud was weighed, and the weight content of iron oxide in the red mud was 34% of the total weight of the red mud, which was consistent with the situation that the weight content of iron oxide was greater than 29% of the total weight of the red mud. The A / S ratio of the red mud was 1.5 and the N / S ratio was 0.4.

[0146] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.48:1>0.48:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.004:1<0.006:1.

[0147] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=260:460, the mass concentration of caustic soda in the alkali solution is 260g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:460g.

[0148] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.45:1.

[0149] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0150] Comparative Example 1

[0151] Comparative Example 1 and Example 1 are compared. The difference between Comparative Example 1 and Example 1 is:

[0152] A method for recovering sodium and aluminum resources from red mud by using the degassed carbide slag described in the background technology instead of lime.

[0153] Comparative Example 2

[0154] Red mud was weighed, and the weight content of iron oxide was 3% of the total weight of the red mud, satisfying the requirement that the weight content of iron oxide was less than 6% of the total weight of the red mud. In the red mud, A / S was 1.5 and N / S was 0.4.

[0155] Weigh degassed carbide slag, which includes calcium oxide and organic carbon. The weight content m4 of calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3=0.62:1>0.52:1, and the weight content m5 of organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3=0.002:1<0.005:1.

[0156] An improved method for recycling and treating red mud, the method comprising:

[0157] S1. performing a dissolution reaction on red mud, alkali solution and degassed carbide slag to obtain a dissolution product;

[0158] S2. performing solid-liquid separation on the dissolution to obtain liquid products and solid waste respectively;

[0159] Among them, the liquid product is used as circulating mother liquor for alumina production; the solid waste includes ferrohydrite garnet;

[0160] The weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the weight of degassed carbide slag are adjusted according to the weight content of iron oxide.

[0161] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=80:150, the mass concentration of caustic soda in the alkali solution is 80g / L, the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:150g, the total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.25:1.

[0162] The temperature of the dissolution reaction is 270°C, and the time of the dissolution reaction is 60 minutes.

[0163] Comparative Example 3

[0164] Based on the contents disclosed in Comparative Example 2, the following modifications are further made:

[0165] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=120:200, the mass concentration of caustic soda in the alkali solution is 120g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:200g.

[0166] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.30:1.

[0167] The temperature of the dissolution reaction is 260°C, and the time of the dissolution reaction is 60 minutes.

[0168] Comparative Example 4

[0169] Based on the contents disclosed in Comparative Example 2, the following modifications are further made:

[0170] The weight m2 of caustic soda in the alkali solution and the total weight m1 of red mud satisfy the relationship: m2:m1=140:280, the mass concentration of caustic soda in the alkali solution is 140g / L, and the added volume V1 of the alkali solution and the total weight m1 of red mud satisfy the relationship: V1:m1=1L:280g.

[0171] The total weight m3 of degassed carbide slag and the total weight m1 of red mud satisfy the relationship: m3:m1=0.32:1.

[0172] The temperature of the dissolution reaction is 280°C, and the time of the dissolution reaction is 60 minutes.

[0173] Related experiments and effect data:

[0174] The A / S, N / S data and sodium oxide content data of the solid waste obtained from each embodiment and comparative example, as well as the recovery rates of aluminum oxide and sodium oxide, are respectively statistically analyzed, and the results are shown in Figure 1.

[0175] Table 1 The recovery rates of A / S and N / S as well as aluminum oxide and sodium oxide in the solid waste obtained in each embodiment and comparative example

[0176]

[0177] As can be seen from Table 1, an improved method for recycling and treating red mud provided by an embodiment of the present application, the weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the total weight of degassed carbide slag can be adjusted according to the weight content of iron oxide, respectively. For red mud with different iron oxide contents, alkali solution with corresponding mass concentration of caustic soda, alkali solution with corresponding weight content of caustic soda and corresponding added amount of degassed carbide slag are added to promote the sodium silicate slag [Na2O·Al2O3·nSiO2·(6-2n)H2O] in the red mud to fully react with the calcium hydroxide in the degassed carbide slag, so as to better generate solid waste with new mineral ferrohydrite garnet [3CaO·Al2O3(Fe2O3)nSiO2·2H2O], thereby improving the recovery rate of sodium oxide and aluminum oxide components in the red mud, and at the same time increasing the usage of degassed carbide slag. In addition, under the condition that the weight content of iron oxide in red mud is relatively high, the weight content of sodium oxide in solid waste can be controlled within 1%, which can lay a foundation for the comprehensive utilization of solid waste.

[0178] In addition, an improved method for recycling and treating red mud provided in an embodiment of the present application can select appropriate alkali solution and degassed carbide slag according to the iron oxide content of different red muds, thereby promoting the A / S in the recycled solid waste to reach 0.48-0.66 and the N / S to reach 0.01-0.08, and the sodium oxide content in the solid waste is less than 1%. In addition, this method can also promote the recovery rate of aluminum oxide in red mud to reach more than 40% and the recovery rate of sodium oxide to reach more than 50%.

[0179] In addition, an improved method for recycling and treating red mud provided in an embodiment of the present application can promote a sufficient reaction between degassed carbide slag and red mud to effectively replace lime and reduce the consumption of lime resources, thereby increasing the recovery rate of sodium and aluminum resources in red mud to reduce the emission of solid waste.

[0180] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. An improved method for recycling red mud, characterized in that: The red mud contains iron oxide, aluminum oxide and sodium silicate slag, and the weight content of the iron oxide is greater than or equal to 6% of the total weight of the red mud. The method comprises: The red mud, alkali solution and degassed carbide slag are subjected to a dissolution reaction to obtain a dissolution product; Performing solid-liquid separation on the dissolution to obtain a liquid product and solid waste respectively; Wherein, the liquid product is used as circulating mother liquor for alumina production; the solid waste includes ferrohydrite garnet; The weight content of caustic soda in the alkali solution, the mass concentration of caustic soda in the alkali solution and the weight of the degassed carbide slag are adjusted according to the weight content of the iron oxide.

2. The method according to claim 1, characterized in that: When the weight content of iron oxide is greater than or equal to 6% and less than or equal to 11% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(80-180):(60-400), the mass concentration of the caustic soda in the alkali solution is 80g / L-180g / L, and the weight content m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.10-0.40):

1.

3. The method according to claim 2, characterized in that The degassed carbide slag includes calcium oxide and organic carbon. The weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.52:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.005:

1.

4. The method according to claim 1, characterized in that: When the weight content of iron oxide is greater than 11% and less than or equal to 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100-240):(80-450), the mass concentration of the caustic soda in the alkali solution is 100g / L-240g / L, and the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15-0.45):

1.

5. The method according to claim 4, characterized in that The degassed carbide slag includes calcium oxide and organic carbon. The weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:

1.

6. The method according to claim 1, characterized in that When the weight content of the iron oxide is greater than 29% of the total weight of the red mud, the weight m2 of the caustic soda in the alkali solution and the total weight m1 of the red mud satisfy the relationship: m2:m1=(100-280):(100-500), the total weight m3 of the degassed carbide slag and the total weight m1 of the red mud satisfy the relationship: m3:m1=(0.15-0.50):

1.

7. The method according to claim 6, characterized in that The degassed carbide slag includes calcium oxide and organic carbon. The weight content m4 of the calcium oxide and the total weight m3 of the degassed carbide slag satisfy the relationship: m4:m3>0.48:1, and the weight content m5 of the organic carbon and the total weight m3 of the degassed carbide slag satisfy the relationship: m5:m3<0.006:

1.

8. The method according to claim 1, characterized in that The yield of sodium oxide in the sodium silicate slag is positively correlated with the weight content of the iron oxide; the yield of aluminum oxide in the red mud is positively correlated with the weight content of the iron oxide.

9. The method according to claim 1, characterized in that: The temperature of the dissolution reaction is 240° C. to 280° C., and the time of the dissolution reaction is 30 min to 120 min.

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