Method for recycling gallium from lime precipitate for recycling gallium from aluminum oxide mother liquor

Abstract

The method comprises the following steps: A, mixing the lime precipitate with hot water, uniformly stirring and dispersing, adding a strong alkali solution, controlling the pH value to be 10-12, and reacting for 1-4 hours while stirring to obtain a mixed solution A; b, cooling the mixed solution A, and filtering to obtain filtrate and filter residues; taking the filtrate to obtain a gallium-containing pregnant solution; and C, the gallium-containing pregnant solution is sent back to a macroporous resin adsorption procedure for recycling gallium from the mother solution, and gallium recycling is carried out. According to the method, gallium in the gallium-containing lime sediment can be effectively recycled, the problem that the gallium content in the gallium-containing lime sediment is high is solved, and the gallium recycling rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of gallium recovery, and in particular to a method for recovering gallium from lime precipitation by recovering gallium from alumina mother liquor. Background Art

[0002] In the current existing technology, the recovery of gallium from the mother liquor of the alumina system has been widely used in alumina plants, such as the records in the literature "Research on chelating resin in the process of gallium recovery by ion exchange, Yang Mayun, Cai Jun, "Light Metals" 2007 No. 3, pp. 14-16", "CN102010998A, a method for adsorbing gallium from the mother liquor by resin adsorption", and "CN100443601C-A method for producing metallic gallium and co-producing alumina".

[0003] In the prior art, in the process of recovering and extracting gallium from the mother liquor of an alumina system, lime is usually used to precipitate gallium impurities. However, the precipitate inevitably contains some incidental gallium, so it is necessary to recover the gallium in the gallium-containing lime precipitate.

[0004] At present, the commonly used method for washing filter cakes of plate and frame filter presses is: the filter cakes remain inside the filter plates of the plate and frame filter presses, and are washed 1-2 times with 75°C hot water. However, the disadvantage of this method is that the filter cakes cannot be dispersed, resulting in some gallium-rich liquid remaining in the filter cakes after hot water washing, causing gallium loss. According to the semi-quantitative analysis results of lime slag, the average gallium content in lime slag is 3.24%. Based on the annual production of filter cakes of about 320 tons and the water content of filter cakes of 50%, the gallium loss in lime slag is about 5.2 tons / year.

[0005] In summary, the current washing method of alumina plants using hot water to wash filter cakes, because the filter cakes stay inside the filter press plate frame, the filter cakes cannot be dispersed, and the washing water cannot be fully mixed with the filter cakes, resulting in a large amount of gallium-rich liquid remaining in the filter cakes, which ultimately results in a high gallium content in the filter cakes and a large gallium loss in the impurity removal process. Therefore, it is necessary to develop an efficient technology for washing and leaching gallium from lime slag and recycling it. Summary of the invention

[0006] The purpose of the present invention is to provide a method for recovering gallium from lime precipitate by recovering gallium from alumina mother liquor. The method can effectively recover gallium from gallium-containing lime precipitate, solve the problem of high gallium content in gallium-containing lime precipitate, and improve the gallium recovery rate.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] The method for recovering gallium from lime precipitation by recovering gallium from alumina mother liquor comprises the following steps:

[0009] A. Mix the lime precipitate with hot water, stir and disperse evenly, then add strong alkali solution, control the pH at 10-12, and react for 1-4 hours under stirring to obtain mixed solution A;

[0010] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0011] B. Cooling the mixed solution A, filtering it to obtain a filtrate and a filter residue; taking the filtrate to obtain a gallium-rich solution;

[0012] C. The gallium-rich solution is sent back to the macroporous resin adsorption process for recovering gallium from the mother solution to recover gallium.

[0013] In the step A, the hot water temperature is 60-75° C., and the weight ratio of hot water to lime precipitate is 3-7:1.

[0014] The specific operation of step A is as follows:

[0015] First, mix the lime precipitate with hot water equivalent to 0.7-1.5 times its weight, stir evenly, and then add strong alkali solution equivalent to 1-2 times the weight of the lime precipitate while stirring. After the strong alkali solution is added, add hot water until the pH of the mixed liquid system is within the range of 10-12, and then stir to react.

[0016] The strong alkali solution is a sodium hydroxide solution or a potassium hydroxide solution with a weight percentage concentration of 35-40%.

[0017] In the step A, the reaction is carried out under stirring and the reaction liquid is heated to a temperature of 95-120°C.

[0018] In the step B, the reaction solution is cooled to 60-70°C.

[0019] The method of cooling the reaction solution is to add cold water to the mixed solution A under stirring.

[0020] The filter residue obtained in step B is sent to the lime milk tank for repeated use as a sedimentation lime milk additive.

[0021] In the step C, the resin used in the macroporous resin adsorption process is ES-346 resin.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The process flow of recovering gallium by alkaline washing of lime slag involved in the present invention is simple, the required materials such as alkali solution and hot water are low in price and widely available, the treatment process has low energy consumption and short cycle, and it is easy to realize large-scale production.

[0024] 2. In the technical method for recovering gallium by alkaline washing of lime slag involved in the present invention, the gallium leached out by lime precipitation is directly returned to the neutralization and separation step of the impurity removal process for recovery, without the need to build an additional production line, and is easier to promote and apply in the original production process.

[0025] 3. In the technical method for recovering gallium by alkaline washing of lime slag involved in the present invention, the lime slag after gallium recovery can be directly transported to the settling lime milk tank for repeated utilization, without the need for unified storage and disposal, thereby reducing the environmental risks that may exist in the large-scale storage of lime slag. DETAILED DESCRIPTION

[0026] In order to facilitate a better understanding of the present invention, the following examples are used to illustrate the present invention. These examples belong to the protection scope of the present invention, but do not limit the protection scope of the present invention.

[0027] Example 1

[0028] A gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor comprises the following steps:

[0029] A. Mix 100 kg of lime precipitate with 300 kg of hot water at 60 ° C. After stirring and dispersing evenly, add 100 kg of 35% sodium hydroxide solution by weight, control the pH at 10, and stir and react at 95 ° C for 1 hour to obtain a mixed solution A;

[0030] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0031] B. Add cold water to the mixed solution A, cool the mixed solution A to 60° C., filter it to obtain a filtrate and a filter residue; take the filtrate to obtain a gallium-rich solution; take the filter residue and send it to a lime milk tank for repeated use as a sedimentation lime milk additive.

[0032] C. Return the gallium-rich solution to the ES-346 macroporous resin adsorption process for gallium recovery from the mother liquor.

[0033] Example 2

[0034] A gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor comprises the following steps:

[0035] A. Mix 100 kg of lime precipitate with 700 kg of hot water at 75 ° C. After stirring and dispersing evenly, add 200 kg of 40% sodium hydroxide solution by weight, control the pH at 12, and stir and react at 120 ° C for 4 hours to obtain a mixed solution A;

[0036] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0037] B. Add cold water to the mixed solution A, cool the mixed solution A to 70° C., filter it to obtain a filtrate and a filter residue; take the filtrate to obtain a gallium-rich solution; take the filter residue and send it to a lime milk tank for repeated use as a sedimentation lime milk additive.

[0038] C. Return the gallium-rich solution to the ES-346 macroporous resin adsorption process for gallium recovery from the mother liquor.

[0039] Example 3

[0040] A gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor comprises the following steps:

[0041] A. Mix 100 kg of lime precipitate with 500 kg of hot water at 67 ° C. After stirring and dispersing evenly, add 150 kg of 38% potassium hydroxide solution by weight, control the pH at 11, and stir and react at 97 ° C for 2 hours to obtain a mixed solution A;

[0042] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0043] B. Add cold water to the mixed solution A, cool the mixed solution A to 65° C., filter it to obtain a filtrate and a filter residue; take the filtrate to obtain a gallium-rich solution; take the filter residue and send it to a lime milk tank for repeated use as a sedimentation lime milk additive.

[0044] C. Return the gallium-rich solution to the ES-346 macroporous resin adsorption process for gallium recovery from the mother liquor.

[0045] Example 4

[0046] A gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor comprises the following steps:

[0047] A. First, 100 kg of lime precipitate was mixed with 70 kg of hot water at 65 ° C. The mixture was stirred evenly. Then, 160 kg of sodium hydroxide solution with a weight percentage concentration of 38% was added under stirring. Then, 430 kg of hot water was added. At this time, the pH of the mixed solution system was 10.5. Then, the mixture was stirred and reacted at 105 ° C for 3 hours to obtain a mixed solution A.

[0048] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0049] B. Add cold water to the mixed solution A, cool the mixed solution A to 65° C., filter it to obtain a filtrate and a filter residue; take the filtrate to obtain a gallium-rich solution; take the filter residue and send it to a lime milk tank for repeated use as a sedimentation lime milk additive.

[0050] C. Return the gallium-rich solution to the ES-346 macroporous resin adsorption process for gallium recovery from the mother liquor.

[0051] Example 5

[0052] A gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor comprises the following steps:

[0053] A. First, 100 kg of lime precipitate was mixed with 120 kg of hot water at a temperature of 71 ° C. The mixture was stirred evenly. Then, 165 kg of a potassium hydroxide solution having a concentration of 39% by weight was added under stirring. 380 kg of hot water was added. At this time, the pH of the mixed solution system was 11. The mixture was then stirred and reacted at 97 ° C for 3 hours to obtain a mixed solution A.

[0054] The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime;

[0055] B. Add cold water to the mixed solution A, cool the mixed solution A to 63° C., filter it to obtain a filtrate and a filter residue; take the filtrate to obtain a gallium-rich solution; take the filter residue and send it to a lime milk tank for repeated use as a sedimentation lime milk additive.

[0056] C. Return the gallium-rich solution to the ES-346 macroporous resin adsorption process for gallium recovery from the mother liquor.

[0057] Example 6 Process Research Summary

[0058] Example 1

[0059] The effect of different reaction temperatures on the recovery rate of gallium from lime slag leaching was investigated, which specifically included the following steps:

[0060] Six parallel experiments were carried out in six groups of containers. One part of liquid alkali, an alkaline washing solution with a pH of 11 prepared by hot water, and one part of lime slag were put into the containers respectively and stirred continuously to disperse and dissolve the filter cake. The reaction temperatures of each group were 70, 80, 90, 100, 110, and 120°C, respectively. The reaction time was 2 hours under stirring. After the reaction, the feed liquid was filtered and the solid phase was taken for semi-quantitative analysis to study the recovery rate of gallium leached from lime slag.

[0061] Table 1 Effect of different reaction temperatures on gallium recovery from lime slag leaching

[0062] Group pH value of washing liquid Reaction time (h) Reaction temperature (℃) Recovery rate (%) 1 11 2 70 45.6 2 11 2 80 49.8 3 11 2 90 55.2 4 11 2 100 75.2 5 11 2 110 75.5 6 11 2 120 75.1

[0063] Example 2

[0064] The effect of different pH values ​​of washing liquid on the recovery rate of gallium leaching from lime slag was investigated, which specifically included the following steps:

[0065] Eight parallel experiments were carried out in eight groups of containers. Alkaline washing solutions with pH values ​​of 7, 8, 9, 10, 11, 12, 13, and 14 and one portion of lime slag were placed in eight different containers and stirred continuously to disperse and dissolve the filter cake. The reaction temperature was 100°C and the reaction time was 2 hours under stirring. After the reaction, the feed liquid was filtered and the solid phase was taken for semi-quantitative analysis to study the recovery rate of gallium leached from lime slag.

[0066] Table 2 Effect of pH value of washing liquid on gallium recovery rate of lime slag leaching

[0067] Group pH value of washing liquid Reaction time (h) Reaction temperature (℃) Recovery rate (%) 1 7 2 100 50.1 2 8 2 100 51.2 3 9 2 100 55.7 4 10 2 100 72.2 5 11 2 100 72.1 6 12 2 100 72.5 7 13 2 100 70.1 8 14 2 100 69.8

[0068] Example 3

[0069] The effect of different reaction times on the recovery rate of gallium from lime slag leaching was investigated, which specifically included the following steps:

[0070] Eight parallel experiments were carried out in eight groups of containers, in which one portion of washing liquid (pH 11 alkaline washing liquid) and one portion of lime slag were put into each container and stirred continuously to disperse and dissolve the filter cake. The reaction temperature was 100°C, and the reaction time of each group was 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4 hours under stirring. After the reaction, the feed liquid was filtered and the solid phase was taken for semi-quantitative analysis to study the recovery rate of gallium leaching from lime slag.

[0071] Table 3 Effect of different reaction times on gallium recovery from lime slag leaching

[0072] Group pH value of washing liquid Reaction time (h) Reaction temperature (℃) Recovery rate (%) 1 11 0.5 100 35.7 2 11 1 100 46.9 3 11 1.5 100 69.7 4 11 2 100 75.5 5 11 2.5 100 75.6 6 11 3 100 75.3 7 11 3.5 100 75.4 8 11 4 100 75.5

[0073] It can be seen from the above results that in the technical method for recovering gallium by alkaline washing of lime slag involved in the present invention, when the pH of the alkaline washing solution is controlled at 10-12, the reaction time is controlled at 2 hours, and the reaction temperature is controlled at 100°C, the consumption of various materials and energy is minimized, and the leaching recovery rate of gallium in the lime slag is the highest. In actual production applications, the above-mentioned process reaction process parameters are the best choice.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0075] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for recovering gallium from lime precipitation by recovering gallium from alumina mother liquor, characterized in that: The following steps are involved: A. Mix the lime precipitate with hot water, stir and disperse evenly, then add strong alkali solution, control the pH at 10-12, and react for 1-4 hours under stirring to obtain mixed solution A; The lime precipitate is: the precipitate obtained by filtering and separating the filtrate of the alumina mother liquor after the alumina mother liquor is extracted with a macroporous resin and separated by alkali precipitation and treated with lime; B. Cooling the mixed solution A, filtering it to obtain a filtrate and a filter residue; taking the filtrate to obtain a gallium-rich solution; C. The gallium-rich solution is sent back to the macroporous resin adsorption process for recovering gallium from the mother solution to recover gallium.

2. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1, characterized in that: In the step A, the hot water temperature is 60-75° C., and the weight ratio of hot water to lime precipitate is 3-7:

1.

3. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1, characterized in that: The specific operation of step A is as follows: First, mix the lime precipitate with hot water equivalent to 0.7-1.5 times its weight, stir evenly, and then add strong alkali solution equivalent to 1-2 times the weight of the lime precipitate while stirring. After the strong alkali solution is added, add hot water until the pH of the mixed liquid system is within the range of 10-12, and then stir to react.

4. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1 or 3, characterized in that: The strong alkali solution is a sodium hydroxide solution or a potassium hydroxide solution with a weight percentage concentration of 35-40%.

5. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1, characterized in that: In the step A, the reaction is carried out under stirring and the reaction liquid is heated to a temperature of 95-120°C.

6. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 5, characterized in that: In the step B, the reaction solution is cooled to 60-70°C.

7. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 6, characterized in that: The method of cooling the reaction solution is to add cold water to the mixed solution A under stirring.

8. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1, characterized in that: The filter residue obtained in step B is sent to the lime milk tank for repeated use as a sedimentation lime milk additive.

9. The gallium recovery method in lime precipitation for recovering gallium from alumina mother liquor according to claim 1, characterized in that: In the step C, the resin used in the macroporous resin adsorption process is ES-346 resin.