Method for recovering tin from tellurium precipitation liquid

Abstract

Based on the characteristic that tin tetrachloride is easy to hydrolyze, efficient extraction of tin in the tellurium-deposited liquid is achieved through a two-step method of neutralization impurity removal and hydrolysis tin deposition, the pH value is adjusted firstly, stirring impurity removal is conducted, then heating hydrolysis tin deposition is conducted, the direct recovery rate of tin is 95% or above, the tin content of a product is also as high as 40% or above, and the method is suitable for industrial production. The lead content is lower than 0.5%, the chlorine content is lower than 2%, compared with an existing conventional neutralization precipitation method, the alkali liquor used in the method is little, and the impurity rate in the obtained tin material is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metal recovery, and particularly relates to a method for recovering tin from post-tellurium precipitation liquid. BACKGROUND

[0002] Tin (Sn) is an important metal resource, known as "green metal", adjacent to germanium, indium, antimony and lead in the periodic table, and similar in properties. Due to the low melting point, good plasticity, corrosion resistance, fatigue resistance and non-toxicity of tin metal, it is widely used in various fields such as modern industry, national defense construction and cutting-edge science. In the process of copper smelting, part of the tin associated with copper ore enters the copper anode plate in the form of tin dioxide, and after electrolysis, it remains in the copper anode mud. A certain large smelting plant in China uses the process of pretreatment-sulfation roasting-copper separation by water leaching-gold separation by chlorination-silver separation by sodium sulfide to treat the anode mud, part of which will be dispersed in the gold separation process, and then enter the post-tellurium precipitation liquid through the gold separation-platinum palladium separation-tellurium precipitation process, and finally be precipitated into carbon copper by neutralization.

[0003] The post-tellurium precipitation liquid is a high-acid chlorosalt wastewater (acidity is more than 100 g / L), which mainly contains valuable elements such as tin and copper, and the tin element exists in the form of tin tetrachloride. For the recovery of tin in acidic chlorosalt wastewater, many predecessors have carried out a lot of research, and in the existing technical solutions, there are neutralization precipitation method, ammonia salt tin precipitation method and reduction displacement method. Compared with other methods, the neutralization precipitation method is the most commonly used method due to its simple operation and low cost. The specific steps of the neutralization precipitation method are: adding alkali to the post-tellurium precipitation liquid to adjust the pH value to more than 1, so as to promote the direct formation of hydroxide or other insoluble compounds of tin ions to precipitate and separate out. However, the neutralization precipitation method needs to consume a large amount of alkali to adjust the pH value, which increases the running cost, and the obtained tin-containing material has high impurity content (Pb, As, Sb, etc.), which makes the subsequent separation and purification difficult. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a method for recovering tin from post-tellurium precipitation liquid with high tin recovery rate and low impurity content.

[0005] To solve the above technical problems, the following technical solutions are adopted: A method for recovering tin from post-tellurium precipitation liquid, comprising the following steps: S1, adjusting the pH value of the post-tellurium precipitation liquid to be in the range of 0.1-0.6 and then stirring and removing impurities, filtering to obtain pretreated liquid; S2, stirring and hydrolyzing the pretreated liquid at a temperature of 50-90℃, filtering to obtain tin precipitation residue; S3, washing and drying the tin precipitation residue to obtain tin material.

[0006] As a further improvement of the above technical solution: In step S1, the pH regulator is at least one of sodium hydroxide, sodium carbonate, sodium sulfide and calcium hydroxide.

[0007] In step S1, the mass fraction of the pH regulator is 30-40%.

[0008] In step S1, the stirring time of the impurity removal reaction is 0.5-1h.

[0009] In step S1, the initial acidity of the tellurium precipitation liquid is 100-160g / L.

[0010] In step S2, the stirring time of the hydrolysis reaction is 0.5-3h.

[0011] Compared with the prior art, the method has the following beneficial effects: The method for recovering tin from the tellurium precipitation liquid is simple in operation and short in process flow. Based on the easy hydrolysis of tin tetrachloride, the method realizes efficient extraction of tin from the tellurium precipitation liquid by adopting a two-step method of "neutralization and impurity removal-hydrolysis and tin precipitation". The pH value is adjusted first, then the impurities are removed by stirring, and then the tin is precipitated by heating and hydrolysis. The direct recovery rate of tin is above 95%, the tin content in the product is above 40%, the lead content is below 0.5%, and the chlorine content is below 2%. Compared with the conventional neutralization and precipitation method, the method uses less alkali liquor and has lower impurity rate in the obtained tin material. DETAILED DESCRIPTION

[0012] The application will be further described below. Unless otherwise specified, the instruments or materials used in the application are commercially available.

[0013] Example 1 The method for recovering tin from the tellurium precipitation liquid in this example includes the following steps: S1, take 1L of tellurium precipitation liquid with an initial acidity of 160g / L, keep stirring, add 32% sodium hydroxide solution to adjust the pH value to 0.2, then filter after stirring for 1h to obtain pretreated liquid. Under the same acidity, the higher the pH value, the more alkali is needed. In this step, the target pH value is low, and less alkaline reagent is used. This step removes part of the impurities in the tellurium precipitation liquid, especially lead.

[0014] In this example, the pH value is 0.2. In other examples, the pH value can be in the range of 0.1-0.6 to achieve the same or similar technical effects. When the pH value is greater than 0.6, the tin will start to precipitate and be lost from the pretreated liquid, which will affect the final yield.

[0015] S2, heat the pretreated liquid to 60℃, stir for 3h for hydrolysis reaction, and then filter to obtain tin precipitation residue.

[0016] In this embodiment, the stirring hydrolysis reaction temperature is 60℃, and in other embodiments, the temperature can be in the range of 50-90℃ to achieve the same or similar technical effects, and if not in this range, the tin direct recovery rate will decrease.

[0017] S3, washing and drying the tin residue to obtain tin material.

[0018] In this embodiment, 7.27g of tin material is obtained, and the tin direct recovery rate from the tellurium precipitation liquid to the tin material is 97.86%. The elemental composition of the tellurium precipitation liquid is shown in Table 1, and the elemental composition of the tin material is shown in Table 2.

[0019] Example 2 The method for recovering tin from the tellurium precipitation liquid in this embodiment comprises the following steps: S1, taking 1L of tellurium precipitation liquid with an initial acidity of 160g / L, keeping stirring, adding calcium hydroxide to adjust the pH value to 0.5, stirring for 1h to remove impurities, and then filtering to obtain a pretreated liquid; S2, heating the pretreated liquid to 80℃, stirring for 3h to hydrolyze, and then filtering to obtain a tin residue.

[0020] S3, washing and drying the tin residue to obtain tin material.

[0021] In this embodiment, 7.27g of tin material is obtained, and the tin direct recovery rate from the tellurium precipitation liquid to the tin material is 97.86%. The elemental composition of the tellurium precipitation liquid is shown in Table 1, and the elemental composition of the tin material is shown in Table 2.

[0022] Comparative Example 1 The method for recovering tin from the tellurium precipitation liquid in this embodiment comprises the following steps: S1, taking 1L of tellurium precipitation liquid with an initial acidity of 160g / L, keeping stirring, adding 32% sodium hydroxide solution to adjust the pH value to 1, stirring for 1h, and then filtering to obtain a tin residue.

[0023] S2, washing and drying the tin residue to obtain tin material.

[0024] In this embodiment, 7.27g of tin material is obtained, and the tin direct recovery rate from the tellurium precipitation liquid to the tin material is 97.86%. The elemental composition of the tellurium precipitation liquid is shown in Table 1, and the elemental composition of the tin material is shown in Table 2.

[0025] Compared with each embodiment of the present application, the tin material obtained by the neutralization and precipitation method in Comparative Example 1 has high impurity content of As, Sb, Pb, etc., and in order to ensure high tin content in the tin material, more liquid alkali needs to be used when adjusting the pH value, and the cost is relatively high. Although the quality of the tin material product obtained in Comparative Example 1 is more, the tin content in the product is low.

[0026] Table 1 Elemental composition of the tellurium precipitation liquid

[0027] Table 2 Elemental composition of tin materials

[0028] While the present application has been disclosed in connection with the preferred embodiments thereof, it should be understood that other embodiments can perform similar functions and / or achieve similar results. For example, any of the elements of an embodiment can be duplicated and / or combined with those of another embodiment to achieve similar results. Furthermore, any of the known equivalents of the disclosed embodiments can be utilized without departing from the present application.

Claims

1. A method for recovering tin from tellurium precipitation solution, characterized in that: Includes the following steps: S1. After adjusting the pH value of the liquid after tellurium precipitation to the range of 0.1~0.6, stir to remove impurities, filter, and obtain the pretreated liquid; S2. The pretreated liquid is stirred and hydrolyzed at 50~90℃, then filtered to obtain tin precipitate residue. S3. After cleaning and drying the tin slag, tin material is obtained.

2. The method for recovering tin from tellurium precipitation solution according to claim 1, characterized in that: In step S1, a pH adjuster is added to adjust the pH value. The pH adjuster is at least one of sodium hydroxide, sodium carbonate, sodium sulfide, and calcium hydroxide.

3. The method for recovering tin from tellurium precipitation solution according to claim 2, characterized in that: In step S1, the mass fraction of the pH adjuster is 30-40%.

4. The method for recovering tin from tellurium precipitation solution according to claim 1, characterized in that: In step S1, the stirring and impurity removal reaction time is 0.5~1h.

5. The method for recovering tin from tellurium precipitation solution according to claim 1, characterized in that: In step S1, the initial acidity of the liquid after tellurium precipitation is 100~160 g / L.

6. The method for recovering tin from tellurium precipitation solution according to claim 1, characterized in that: In step S2, the stirring hydrolysis reaction takes 0.5 to 3 hours.

Images