Preparation method of cuprous oxide, cuprous salt and preparation method of cuprous salt

Abstract

The invention discloses a preparation method of cuprous oxide, cuprous salt and a preparation method thereof, the preparation method of cuprous oxide comprises the following steps: alkali is added into an arsenic-containing copper solution for reaction, cuprous oxide is obtained after solid-liquid separation, the arsenic-containing copper solution meets the condition that 2cAs < 3 + > is greater than cCu < 2 + >, cAs < 3 + > is the molar concentration of trivalent arsenic in the arsenic-containing copper solution, and the cuprous salt is the molar concentration of trivalent arsenic in the arsenic-containing copper solution. CCu < 2 + > is the molar concentration of bivalent copper in the arsenic-containing copper solution. An alkaline reagent is added into an arsenic-containing copper solution with specific arsenic and copper contents to react to prepare a cuprous oxide raw material, and the cuprous oxide raw material is further converted into cuprous salt, so that not only can effective separation of arsenic and copper be realized, but also a high-purity cuprous salt product can be obtained. The method is simple in technological process and easy and convenient to operate and has good implementability and industrial application prospects, and the obtained cuprous salt product is excellent in quality and has high application value.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of cuprous salt synthesis, in particular to a preparation method of cuprous oxide, a cuprous salt and a preparation method thereof. BACKGROUND

[0002] With the increasing shortage of copper resources and the increasing environmental protection requirements, the comprehensive utilization of arsenic-containing copper materials has become an important research direction in the field of hydrometallurgy. The arsenic-containing copper solution is mainly derived from the waste liquid generated in the wet leaching process or the hydrometallurgical process of the arsenic-containing copper material, such as the acid leaching solution of white dust, the waste liquid generated in copper electrolytic refining, etc. Such solution usually contains high concentrations of copper ions and arsenic elements. If not properly treated and directly discharged, it will not only cause waste of valuable metal resources, but also cause serious environmental pollution.

[0003] At present, the conventional treatment method for the arsenic-containing copper solution mainly includes solvent extraction method for separating copper and arsenic, or chemical precipitation method for first precipitating copper and then precipitating arsenic. The copper residue obtained by precipitating copper needs to be further smelted to recover copper, and the arsenic-containing residue needs to be stabilized to meet the environmental protection requirements. In addition, some technologies also attempt to use arsenic sulfide slag as a precipitant to recover copper from the arsenic-containing copper solution. For example, patent CN105603466A discloses a method for selectively precipitating copper ions in copper electrolyte by using arsenic sulfide slag to realize copper-arsenic separation. The method realizes the recycling of resources to some extent.

[0004] However, in the existing technical process, there are problems such as complex process steps, large reagent consumption, many by-products and low added value of the final product. Especially, there are still technical bottlenecks in directly realizing efficient recovery and high-value conversion of copper from the arsenic-containing copper solution. Therefore, how to separate arsenic effectively while converting copper into products with higher utilization value is one of the key challenges in the current treatment technology of arsenic-containing copper solution.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of cuprous oxide, a cuprous salt and a preparation method thereof, so as to improve the above technical problems.

[0007] The present application is realized as follows: In a first aspect, the present application provides a preparation method of cuprous oxide, which comprises: reacting an arsenic-containing copper solution with alkali, and obtaining cuprous oxide after solid-liquid separation, wherein the arsenic-containing copper solution satisfies 2 cAs 3+ > cCu 2+ , cAs 3+This refers to the molar concentration of trivalent arsenic in the arsenic-containing copper solution. cCu 2+ The molar concentration of divalent copper in the arsenic-containing copper solution is given.

[0008] In an optional implementation, OH - The amount of alkali added is 1 to 1.2 times the theoretical amount, calculated according to the following formula: ,in, m 碱 For the quality of alkali, c Cu The molar concentration of total Cu in the arsenic-containing copper solution is given. c As The molar concentration of total As in the arsenic-containing copper solution is given. v The volume is the arsenic-containing copper solution. M 碱 denoted as α, where α is the molar mass of the base.

[0009] In an optional embodiment, the alkali includes at least one of sodium hydroxide and potassium hydroxide; And / or, the arsenic-containing copper solution is derived from flue gas acid leaching solution, copper electrolysis solution, or acid leaching solution of arsenic-containing copper solid waste.

[0010] In an optional embodiment, the reaction temperature for generating cuprous oxide is 20°C to 100°C, preferably 70°C to 90°C, and the reaction time is at least 15 min, preferably 15 min to 60 min; Preferably, the reaction proceeds until the precipitate turns brick red; more preferably, the reduction degree reaches 99% or higher, wherein the reduction degree is the percentage of monovalent copper in the prepared cuprous oxide relative to the total copper.

[0011] Secondly, the present invention provides a method for preparing cuprous salt, which includes using cuprous oxide prepared by any of the preparation methods described in the foregoing embodiments as a monovalent copper raw material to prepare cuprous salt.

[0012] In an optional embodiment, it includes: adding water to the cuprous oxide to make a slurry, then adding acid and thiocyanate to react, and separating the solid and liquid to obtain cuprous thiocyanate and copper-free liquid.

[0013] In an optional embodiment, the reaction temperature for adding acid and thiocyanate is 20°C to 100°C, preferably 70°C to 95°C, and the reaction time is at least 15 min, preferably 30 min to 60 min.

[0014] In an optional embodiment, the acid is sulfuric acid, and the amount of sulfuric acid used is 0.96 to 1.5 times the theoretical amount, preferably 1.1 to 1.2 times.

[0015] In an optional embodiment, the acid is sulfuric acid, and the thiocyanate includes at least one of sodium thiocyanate, potassium thiocyanate, and ammonium thiocyanate.

[0016] Thirdly, the present invention provides a cuprous salt, which is prepared by the cuprous salt preparation method described in any of the foregoing embodiments. Preferably, the cuprous salt is cuprous thiocyanate, wherein the cuprous thiocyanate has a purity ≥99%, contains arsenic <0.0005%, and has a whiteness ≥80.

[0017] This invention offers the following advantages: By adding an alkaline reagent to an arsenic-containing copper solution with specific arsenic and copper content to induce a reaction and prepare cuprous oxide raw material, which is then further converted into cuprous salt, this process not only achieves effective separation of arsenic and copper but also yields high-purity cuprous salt products. The method features a simple process flow, easy operation, good feasibility, and promising prospects for industrial application. The resulting cuprous salt product is of excellent quality and has high application value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A process flow diagram for preparing cuprous oxide from an arsenic-containing copper solution provided for embodiments of the present invention; Figure 2 The present invention provides a process flow for preparing cuprous thiocyanate from an arsenic-containing copper solution. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges 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., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0022] In the description of this invention, the terms "comprising," "including," etc., mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means 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 both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0023] The following provides a detailed description of a method for preparing cuprous oxide, a cuprous salt, and the preparation method thereof provided by this invention.

[0024] See Figure 1 Some embodiments of the present invention provide a method for preparing cuprous oxide, comprising: reacting an arsenic-containing copper solution with an alkali, and obtaining cuprous oxide after solid-liquid separation, wherein the arsenic-containing copper solution satisfies 2 cAs 3+ > cCu 2+ , cAs 3+ This represents the molar concentration of trivalent arsenic in the arsenic-containing copper solution. cCu 2+ This represents the molar concentration of divalent copper in an arsenic-containing copper solution.

[0025] It should be noted that the arsenic-containing copper solution is derived from flue gas acid leaching solution, copper electrolysis solution, or acid leaching solution of arsenic-containing copper solid waste, etc. The cuprous oxide obtained by this method also contains a small amount of arsenic and other metals, which can be used as raw materials for preparing other cuprous salts. Arsenic and other metals can be separated and removed during further preparation of cuprous salts.

[0026] In some implementations, the separated arsenic-containing copper-removing liquid undergoes arsenic-free treatment. For example, reagents can be added to generate sparingly soluble arsenic compounds, such as iron salt precipitates, sulfide precipitates, and calcium salt precipitates. Alternatively, arsenic species can be captured by further utilizing adsorbents (metal oxides, modified biochar, mineral materials, etc.) to achieve deep purification.

[0027] The core mechanism of the above method lies in the fact that, under alkaline conditions, trivalent arsenic can reduce divalent copper to monovalent copper, and the reaction is relatively complete, requiring 2... cAs 3+ > cCu 2+ The main reactions are as follows: (1) (2) (3) (4) (5) In some embodiments, the base includes at least one of sodium hydroxide and potassium hydroxide; with OH - Based on the molar amount, the amount of alkali added is 1 to 1.2 times the theoretical amount, which is calculated using the following formula: ,in, m 碱 For the quality of alkali, c Cu This represents the molar concentration of total Cu in the arsenic-containing copper solution. c As This represents the molar concentration of total As in an arsenic-containing copper solution. v The volume is the arsenic-containing copper solution. M 碱 denoted as α, where α is the molar mass of the base.

[0028] Insufficient alkali addition will lead to incomplete reaction and low reduction; conversely, excessive alkali addition will cause partial dissolution of copper, resulting in higher Cu content in the solution. 2+ The concentration rises, causing a "reverse dissolution" phenomenon, resulting in copper loss. The separation of arsenic and copper is incomplete, which is not conducive to the subsequent harmless treatment of arsenic.

[0029] In some embodiments, the reaction temperature for producing cuprous oxide is 20°C to 100°C, such as 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C, preferably 70°C to 90°C, and the reaction time is at least 15 minutes, such as 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, or 80 minutes, preferably 15 minutes to 60 minutes. Generally, the higher the reaction temperature, the shorter the corresponding reaction time. To improve production efficiency, the reaction is generally not carried out at room temperature.

[0030] It should be noted that in the embodiments of the present invention, the reaction temperature of the above reaction should not be too high. On the one hand, 100°C is the boiling point under normal pressure. If the temperature is exceeded, the solution will boil violently and generate a large amount of steam, which will increase the cost. On the other hand, excessively high temperature will easily cause volatile arsenic-containing substances to volatilize, reduce the arsenic content of the solution, and pollute the environment.

[0031] In some implementations, the reaction is considered complete when the precipitate turns brick red and the reduction degree reaches 99% or more.

[0032] In some implementations, the solid-liquid separation method may be filtration.

[0033] Some embodiments of the present invention also provide a method for preparing cuprous salt, which includes using cuprous oxide prepared by the preparation method described in any of the foregoing embodiments as a copper raw material to prepare cuprous salt.

[0034] For example, cuprous oxide is prepared as a copper raw material to prepare cuprous thiocyanate.

[0035] See Figure 2 First, cuprous oxide is prepared according to the aforementioned method. Then, cuprous oxide is mixed with water to form a slurry, followed by the addition of acid and thiocyanate for reaction. After solid-liquid separation, cuprous thiocyanate and the copper-free solution are obtained. The main reactions are as follows: This equation serves as the theoretical basis for calculating the amounts of acid and thiocyanate required, i.e., 1 mol of cuprous oxide requires 2 mol of H₂O. + 1 mol of cuprous oxide requires 2 mol of SCN - .

[0036] In some embodiments, the acid may be hydrochloric acid or sulfuric acid, since arsenic-containing copper solutions are generally sulfuric acid systems, with sulfuric acid being preferred as it does not introduce other anions. Thiocyanate includes, but is not limited to, at least one of sodium thiocyanate, potassium thiocyanate, and ammonium thiocyanate.

[0037] For example, the acid is sulfuric acid, and the amount of sulfuric acid used is 0.96 to 1.5 times the theoretical amount, preferably 1.1 to 1.2 times. When the amount of sulfuric acid is insufficient, unreacted cuprous oxide will enter the cuprous thiocyanate product, making it difficult to meet the standard requirements for purity and impurity content; while when the amount of sulfuric acid is too high, it will have multiple adverse effects: firstly, it will lead to a significant increase in acid consumption; secondly, excessive sulfuric acid will significantly increase the acidity of the reaction system, which may cause the thiocyanate ion (SCN) to... - Part of it is converted into thiocyanate HSCN, especially under high temperature conditions. The HSCN produced is unstable and undergoes many side reactions, generating byproducts that are detrimental to product purity. Thirdly, when the sulfuric acid in the system is too acidic, the disproportionation reaction rate of copper ions will be significantly accelerated. With more divalent copper ions, more black copper thiocyanate will be generated. Most of it reacts with the copper powder produced by disproportionation to form cuprous thiocyanate, and a small part decomposes on its own, generating a series of side reactions, reducing product purity and whiteness, and increasing the risk of environmental pollution.

[0038] In some embodiments, the reaction temperature for adding acid and thiocyanate is 20°C to 100°C, such as 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C, preferably 20°C to 100°C, and the reaction time is at least 15 minutes, such as 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, or 80 minutes, preferably 30 minutes to 60 minutes. Generally, a higher temperature results in a shorter reaction time.

[0039] By controlling the appropriate reaction temperature and reaction time, the reaction can be completed, resulting in a cuprous thiocyanate product with better quality, such as whiteness and arsenic content.

[0040] In some implementations, the copper-free solution can be directly returned to the leaching of cuprous oxide to reduce reagent consumption; when the concentration of other metal ions, such as nickel and zinc, in the copper-free solution exceeds 10 g / L, the solution is opened, and valuable metals are recovered using conventional methods.

[0041] Some embodiments of the present invention also provide a cuprous salt, which is prepared by the cuprous salt preparation method described in any of the foregoing embodiments. In some embodiments, the cuprous salt is cuprous thiocyanate, the purity of cuprous thiocyanate is ≥99%, the arsenic content is <0.0005%, and the whiteness is ≥80.

[0042] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0043] Example 1 This embodiment provides a method for preparing cuprous thiocyanate, which includes the following steps: Step 1: Add 1.2 times the theoretical amount of sodium hydroxide to the arsenic-containing copper solution, then heat the solution to 95°C and maintain the temperature for 60 minutes; then filter to obtain cuprous oxide slag. The As ion content and Cu ion content of the arsenic-containing copper solution are shown in Table 1.

[0044] Step 2: Add water directly to the cuprous oxide slag to make a slurry, then add 1.1 times the theoretical amount of sulfuric acid and 1 times the theoretical amount of sodium thiocyanate. Then control the temperature of the solution system at 85°C and react for 60 minutes. After filtration and drying, the product cuprous thiocyanate is obtained.

[0045] Examples 2 to 5 The preparation method of cuprous thiocyanate provided in Examples 2 to 5 differs from that in Example 1 only in the As ion content and Cu ion content of the arsenic-containing copper solution in step 1, as shown in Table 1. The other steps and conditions are the same.

[0046] Example 6 Example 6 provides a method for preparing cuprous thiocyanate, which differs from Example 1 only in step 2: the cuprous oxide slag is directly mixed with water to form a slurry, then hydrochloric acid is added. After the cuprous oxide is completely dissolved and there are no solid particles, sodium thiocyanate with a theoretical amount of 1 is added. The temperature of the solution system is then controlled at 85°C, and the reaction is carried out for 60 minutes. After filtration and drying, the product cuprous thiocyanate is obtained.

[0047] Example 7 Example 7 provides a method for preparing cuprous thiocyanate, which differs from Example 1 only in that the amount of alkali added in step 1 is 1.0 times the theoretical amount, while the other steps and conditions are the same.

[0048] Example 8 Example 8 provides a method for preparing cuprous thiocyanate, which differs from Example 1 only in that the reaction temperature in step 1 is 40°C, while the other steps and conditions are the same.

[0049] Example 9 Example 9 provides a method for preparing cuprous thiocyanate, which differs from Example 1 only in that the amount of sulfuric acid used in step 2 is 0.92 times the theoretical amount, while the other steps and conditions are the same.

[0050] Example 10 Example 10 provides a method for preparing cuprous thiocyanate, which differs from Example 1 only in that the reaction temperature in step 2 is 65°C, while the other steps and conditions are the same.

[0051] Comparative Example 1 The only difference between this comparative example and Example 1 is the As ion content and Cu ion content of the arsenic-containing copper solution, as shown in Table 1. The other steps and conditions are the same.

[0052] Table 1

[0053] The cuprous thiocyanate products of the examples and comparative examples were tested for their properties. The elemental content of the products was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), the thiocyanate content was determined by Volhard back titration, and the whiteness was determined by a whiteness meter. The test results are shown in Table 2.

[0054] Table 2

[0055] It should be noted that in Comparative Example 1, cuprous oxide was observed to be dark orange in step 1, unlike the brick red color of other examples. In step 2, cuprous thiocyanate was synthesized, and a lot of gas was observed to be generated, producing bubbles. This was a side reaction caused by the decomposition of black copper thiocyanate, which polluted the air.

[0056] In summary, this invention proposes a process for preparing cuprous salts based on an arsenic-containing copper solution. Specifically, an alkaline reagent is added to an arsenic-containing copper solution with a specific arsenic and copper content, causing a chemical reaction to generate cuprous oxide, which is further converted into cuprous salt. This process has the following significant advantages: First, it achieves efficient separation of arsenic and copper; second, it yields high-purity cuprous salt products. From a process perspective, the method has a reasonable flow design and is simple and easy to operate, exhibiting not only good operability but also broad prospects for industrial application. Experimental results show that the cuprous salt product prepared using this process has high purity and excellent performance, possessing significant industrial application value.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing cuprous oxide, characterized in that, It includes: An arsenic-containing copper solution is reacted with alkali, and after solid-liquid separation, cuprous oxide is obtained. The arsenic-containing copper solution satisfies condition 2. cAs 3+ > cCu 2+ , cAs 3+ This refers to the molar concentration of trivalent arsenic in the arsenic-containing copper solution. cCu 2+ The molar concentration of divalent copper in the arsenic-containing copper solution is given.

2. The method for preparing cuprous oxide according to claim 1, characterized in that, With OH - The amount of alkali added is 1 to 1.2 times the theoretical amount, calculated according to the following formula: ,in, m 碱 For the quality of alkali, c Cu The molar concentration of total Cu in the arsenic-containing copper solution is given. c As The molar concentration of total As in the arsenic-containing copper solution is given. v The volume of the copper solution containing arsenic is given. M 碱 denoted as α, where α is the molar mass of the base.

3. The method for preparing cuprous oxide according to claim 1 or 2, characterized in that, The alkali includes at least one of sodium hydroxide and potassium hydroxide; And / or, the arsenic-containing copper solution is derived from flue gas acid leaching solution, copper electrolysis solution, or acid leaching solution of arsenic-containing copper solid waste.

4. The method for preparing cuprous oxide according to claim 1 or 2, characterized in that, The reaction temperature for the formation of cuprous oxide is 20°C to 100°C, preferably 70°C to 90°C, and the reaction time is at least 15 min, preferably 15 min to 60 min. Preferably, the reaction proceeds until the precipitate turns brick red; more preferably, the reduction degree reaches 99% or higher.

5. A method for preparing a cuprous salt, characterized in that, It includes preparing cuprous salts using cuprous oxide prepared by the preparation method according to any one of claims 1 to 4 as a monovalent copper raw material.

6. The method for preparing cuprous salt according to claim 5, characterized in that, It includes: After adding water to make a slurry, acid and thiocyanate are added to react. After solid-liquid separation, cuprous thiocyanate and copper-free liquid are obtained.

7. The method for preparing cuprous salt according to claim 6, characterized in that, The reaction temperature for adding acid and thiocyanate is 20°C to 100°C, preferably 70°C to 95°C, and the reaction time is at least 15 min, preferably 30 min to 60 min.

8. The method for preparing cuprous salt according to claim 6, characterized in that, The acid is sulfuric acid, and the amount of sulfuric acid used is 0.96 to 1.5 times the theoretical amount, preferably 1.1 to 1.2 times.

9. The method for preparing cuprous salt according to claim 6, characterized in that, The acid is sulfuric acid, and the thiocyanate includes at least one of sodium thiocyanate, potassium thiocyanate, and ammonium thiocyanate.

10. A cuprous salt, characterized in that, It is prepared by the method of preparing cuprous salt according to any one of claims 5 to 9. Preferably, the cuprous salt is cuprous thiocyanate, and the cuprous thiocyanate has a purity of ≥99%, contains arsenic of <0.0005%, and has a whiteness of ≥80.

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