阅读说明：本技术 一种含氰化亚铜的固体废物制备硫酸铜的方法 (Method for preparing copper sulfate from solid waste containing cuprous cyanide ) 是由 周凯 张艳华 徐文彬 何龙 郭杏林 李姗婷 杨林 于 2020-11-25 设计创作，主要内容包括：本发明涉及含氰化亚铜的固体废物资源化处理技术领域,更具体地说,它涉及一种含氰化亚铜的固体废物制备硫酸铜的方法,所述方法包括步骤有：固废溶解、一段氧化、沉淀铜、过滤处理、二段氧化、结晶处理。本发明的目的在于对含氰化亚铜的固体废物中具有回收价值的铜元素进行了回收,制备出无毒的、高纯度的硫酸铜产品,达到变废为宝,同时,本发明方法工艺流程简单、操作安全,解决了含氰化亚铜的固体废物资源化处理难题。(The invention relates to the technical field of solid waste recycling treatment containing cuprous cyanide, in particular to a method for preparing copper sulfate from solid waste containing cuprous cyanide, which comprises the following steps: dissolving solid waste, first-stage oxidation, precipitating copper, filtering, second-stage oxidation and crystallization. The invention aims to recover copper element with recovery value in the solid waste containing cuprous cyanide, prepare a non-toxic and high-purity copper sulfate product, change waste into valuable, and solve the problem of recycling treatment of the solid waste containing cuprous cyanide, wherein the method has simple process flow and safe operation.)

1. A method for preparing copper sulfate from cuprous cyanide-containing solid waste is characterized by comprising the following steps:

(1) solid waste dissolution: adding solid waste containing cuprous cyanide into an ammonium salt solution for dissolving to obtain a dissolved solution;

(2) primary oxidation: adjusting the dissolving solution to be alkaline, and introducing oxidizing gas into the dissolving solution to thoroughly oxidize cuprous ions and cyanide ions to obtain a first reaction solution;

(3) and (3) copper precipitation: adding a copper precipitator into the first reaction solution, adding weak acid to adjust the solution to be acidic after copper ions are fully precipitated, and obtaining a mixed solution;

(4) and (3) filtering treatment: filtering the mixed solution, washing the precipitate with dilute hydrochloric acid and collecting to obtain a filter cake;

(5) secondary oxidation: adding a strong oxidant solution into the filter cake to prepare a copper sulfate solution;

(6) and (3) crystallization treatment: the copper sulfate solution is crystallized to obtain copper sulfate crystals.

2. The method for preparing copper sulfate from cuprous-containing solid waste as claimed in claim 1, wherein said ammonium salt solution is ammonium sulfate and/or ammonium chloride.

3. The method for preparing copper sulfate from cuprous-cyanide-containing solid waste as claimed in claim 2, wherein the concentration of said ammonium sulfate and/or said ammonium chloride is 10% -30%.

4. The method for preparing copper sulfate from cuprous cyanide-containing solid waste as claimed in claim 1, wherein in said primary oxidation step, the pH of said solution is maintained to 8-10 and said oxidizing gas is chlorine dioxide.

5. The method for preparing copper sulfate from cuprous cyanide-containing solid waste as claimed in claim 1, wherein said copper precipitant is sodium hydrosulfide with concentration of 10% -20% and/or sodium sulfide with concentration of 10% -20%.

6. The method for preparing copper sulfate from cuprous cyanide-containing solid waste as claimed in claim 1, wherein said copper precipitation step is performed by adding weak acid to adjust pH to 2-5, wherein said weak acid is dilute hydrochloric acid and/or dilute sulfuric acid.

7. The method for preparing copper sulfate from cuprous cyanide-containing solid waste as claimed in claim 1, wherein said strong oxidant solution is hydrogen peroxide with concentration not less than 35%.

8. The method for preparing copper sulfate from cuprous cyanide-containing solid waste as claimed in claim 1, wherein said crystallization process is: and (3) after the copper sulfate solution is evaporated until a crystallization film appears, cooling to 20-30 ℃ for crystallization, cleaning crystals and collecting to obtain the copper sulfate crystals.

9. The method for preparing copper sulfate from cuprous chloride-containing solid waste as claimed in claim 1, wherein said copper sulfate crystals are dried under vacuum at 40 ℃ for 2h to prepare high purity copper sulfate product.

Technical Field

The invention relates to the technical field of solid waste recycling treatment containing cuprous cyanide, in particular to a method for preparing copper sulfate from solid waste containing cuprous cyanide.

Background

Cuprous cyanide can be widely applied to the industries such as electroplating, pesticides and medicines, and can release hydrogen cyanide highly toxic gas when meeting acid, so that the existing cyanide-containing wastewater treatment technology is mature, and can be roughly divided into two types: a purification method and a recovery method; the former achieves the purpose of purification mainly by degrading and destroying cyanide in the wastewater, while the latter realizes the purification and reutilization of the wastewater by regenerating and recovering the cyanide, but the treatment method of copper-containing cyanide such as cuprous cyanide solid is rare in the industry, the cuprous cyanide solid is directly discharged into rivers without being treated, the environment is seriously polluted, and the human and animal poisoning is caused, so the development of the treatment process of the cuprous cyanide-containing solid waste is urgently needed.

At present, the solid waste containing cuprous cyanide is subjected to resource treatment, which has the following problems: (1) cuprous cyanide belongs to solid waste which is insoluble in water, a common cyanide-containing wastewater treatment method is not suitable for the method, and a recycling treatment process for the cuprous cyanide solid waste is lacked; (2) the solid waste containing cuprous cyanide contains a large amount of copper elements with recovery value, and the non-toxic and high-purity copper sulfate crystal product is difficult to recover from the solid waste containing cuprous cyanide.

Disclosure of Invention

In view of the above problems, the present invention is to provide a method for preparing copper sulfate from cuprous cyanide-containing solid waste, comprising the steps of: the method comprises the steps of solid waste dissolution, primary oxidation, copper precipitation, filtration treatment, secondary oxidation and crystallization treatment, and copper elements with recovery value in the solid waste containing cuprous cyanide are recovered by the method, so that a non-toxic high-purity copper sulfate product is prepared, and the resource utilization of the solid waste containing cuprous cyanide is realized.

The technical purpose of the invention is realized by the following technical scheme, and the method for preparing the copper sulfate from the copper waste containing cyanide is characterized by comprising the following steps of:

(1) solid waste dissolution: adding solid waste containing cuprous cyanide into an ammonium salt solution for dissolving to obtain a dissolved solution;

(2) primary oxidation: adjusting the dissolving solution to be alkaline, and introducing oxidizing gas into the dissolving solution to thoroughly oxidize cuprous ions and cyanide ions to obtain a first reaction solution;

(3) and (3) copper precipitation: adding a copper precipitator into the first reaction solution, adding weak acid to adjust the pH of the solution to acidity after copper ions are fully precipitated, and obtaining a mixed solution;

(4) and (3) filtering treatment: filtering the mixed solution, cleaning precipitates with dilute hydrochloric acid and collecting to obtain a filter cake;

(5) secondary oxidation: adding a strong oxidant solution into the filter cake to prepare a copper sulfate solution;

(6) and (3) crystallization treatment: the copper sulfate solution is crystallized to obtain copper sulfate crystals;

adding solid waste containing cuprous cyanide into the ammonium salt solution for dissolving, and fully stirring to obtain a dissolved solution; adjusting the solution to be alkaline, introducing oxidizing gas, stirring to enable cuprous ions in the solution to fully react with cyanide ions to obtain a first reaction solution, oxidizing the cuprous ions in the solution into copper ions through the oxidizing gas, and thoroughly oxidizing the cyanide ions into carbon dioxide and nitrogen, thereby completing cyanide breaking treatment of the cyanide ions; adding a copper precipitator into the solution to react to generate a copper sulfide precipitate mixed solution, filtering the mixed solution to obtain a filter cake, adding the filter cake washed by dilute hydrochloric acid into a strong oxidant solution, oxidizing the copper sulfide precipitate into copper sulfate under the catalysis of copper ions in the solution to obtain a copper sulfate solution, and crystallizing the copper sulfate solution to obtain copper sulfate crystals.

Preferably, the ammonium salt solution is at least one of ammonium sulfate and ammonium chloride.

Preferably, the concentration of the ammonium sulfate or the ammonium chloride is 10% to 30%, the cuprous cyanide solid is insoluble in water and soluble in ammonia water and an ammonium salt solution, the solid waste containing cuprous cyanide is dissolved by using the ammonium salt solution, and insoluble residues in the solid waste can be separated to obtain the dissolved solution.

Preferably, in the first-stage oxidation step, before oxidizing gas is introduced to fully oxidize cuprous ions and cyanide ions, the pH value of a dissolving solution needs to be adjusted to 8-10, and the step is to prevent generation of highly toxic and volatile cyanogen chloride gas in the subsequent oxidation process; the oxidizing gas is chlorine dioxide gas, the chlorine dioxide gas oxidizes cuprous ions into copper ions, meanwhile, cyanogen breaking treatment of cyanide ions is completed, and the cyanide ions are thoroughly oxidized into nitrogen and carbon dioxide to obtain first reaction liquid. In order to ensure that cuprous ions and cyanide ions are fully oxidized by chlorine dioxide gas, a residual chlorine detector is adopted to monitor the residual chlorine content in the dissolving solution.

Preferably, the copper precipitant added to the first reaction solution is at least one of sodium hydrosulfide or sodium sulfide, the copper sulfide precipitate is generated by reaction, the concentration of the sodium hydrosulfide or the sodium sulfide is 10-20%, and the copper ion in the solution is fully precipitated by fully stirring in the reaction process.

Preferably, when the solution is adjusted to be acidic by adding a weak acid in the copper precipitation step, the pH is 2-5, the weak acid is dilute hydrochloric acid and/or dilute sulfuric acid, and the copper sulfide precipitate has a small Ksp constant and a property of insolubility in a dilute hydrochloric acid and dilute sulfuric acid solution, so that the operation can ensure that the copper sulfide precipitate in the solution is completely separated out.

Preferably, the strong oxidant solution is hydrogen peroxide with the concentration of not less than 35%.

Preferably, the crystallization process is as follows: heating and evaporating the copper sulfate solution until a crystallization film appears, stopping heating, slowly cooling to 20-30 ℃, cooling for crystallization, performing centrifugal filtration after crystallization is finished, and cleaning crystals by using a small amount of water or a saturated copper sulfate solution and collecting to obtain copper sulfate crystals; the filtrate produced in the filtering process and the mother liquor produced after crystallization can be mixed into the copper sulfate solution in the second-stage oxidation step for repeated crystallization treatment, so that the loss of copper sulfate in the crystallization filtering process is reduced.

Preferably, the copper sulfate crystals are dried for 2 hours under the vacuum condition of the temperature of 40 ℃, and a high-purity copper sulfate product is prepared.

The method utilizes the properties that cuprous cyanide solid is insoluble in water and soluble in ammonia water and ammonium salt, adds the solid waste containing cuprous cyanide into the ammonium salt solution, and fully stirs the mixture to dissolve the cuprous cyanide solid, thereby filtering insoluble residues to obtain a dissolved solution; then introducing chlorine dioxide gas to oxidize cuprous ions and cyanide ions in the solution, wherein the chlorine dioxide gas can generate a very small amount of chloric acid and hypochlorous acid in the dissolving process, in order to prevent the chloric acid, the hypochlorous acid and the cyanide ions from reacting to generate virulent and volatile cyanogen chloride gas, the pH of the dissolving solution needs to be adjusted to 8-10, the cuprous ions in the solution are oxidized into copper ions through the oxidation of the chlorine dioxide gas, the cyanide ions are thoroughly oxidized into carbon dioxide and nitrogen, and the cyanide breaking treatment of the cyanide ions is completed; and then adding copper precipitator sodium hydrosulfide or sodium sulfide, reacting to generate copper sulfide precipitate mixed liquor, and further adding dilute hydrochloric acid and dilute sulfuric acid to completely separate out copper ions in the solution after primary precipitation in order to increase the recovery rate of copper elements because the copper sulfide precipitate has a smaller Ksp constant and the property of insolubility in dilute hydrochloric acid and dilute sulfuric acid solution. And finally, adding the filter cake washed by the dilute hydrochloric acid into hydrogen peroxide, obtaining a copper sulfate solution under the catalysis of copper ions in the solution, and performing post-crystallization treatment to obtain copper sulfate crystals.

In conclusion, the invention has the following beneficial effects:

the method has the advantages of simple process flow and safe operation, solves the problem of treatment of the solid cuprous cyanide, effectively treats the solid waste containing the cuprous cyanide as resources, and prevents environmental pollution.

Secondly, the invention recovers the copper element with recovery value in the solid waste, prepares a non-toxic and high-purity copper sulfate product, and achieves the purpose of changing waste into valuable.

Thirdly, the pH value of the solution in the first-stage oxidation step is kept at 8-10, so that generation of highly toxic gas is prevented, complete oxidation of cyanide is ensured, and safety of the method is realized.

Fourthly, the method can repeatedly utilize the mother liquor to further increase the recovery efficiency of the copper element.

Detailed Description

The present invention is described in further detail below with reference to examples, which are intended to facilitate the understanding of the present invention and are not intended to limit the present invention in any way. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

Example 1

(1) Solid waste dissolution: adding 400L of 20% ammonium chloride solution into a dissolving tank, slowly adding 50kg of solid waste containing cuprous cyanide while stirring, fully reacting and dissolving until the mass of the residual solid in the solution is not changed, filtering, and removing insoluble residues to obtain a dissolved solution;

(2) primary oxidation: introducing the dissolved solution into an oxidation precipitation copper tank, adjusting and keeping the pH value of the dissolved solution to 8-10, opening a chlorine dioxide generator, introducing chlorine dioxide gas into the dissolved solution, stirring to enable cuprous ions and cyanide ions in the filtrate to fully react, monitoring the reaction process by a residual chlorine detector, and obtaining a first reaction solution after the reaction is finished;

(3) and (3) copper precipitation: adding a prepared 156L 20% sodium hydrosulfide solution into the first reaction liquid, stirring for reaction for 40min, adding a 10% dilute hydrochloric acid solution, adjusting the pH to 2-3, and continuing the reaction for 30min until the precipitate is insoluble to obtain a mixed solution;

(4) and (3) filtering treatment: the mixture was filtered and washed with a small amount of 10% dilute hydrochloric acid solution to obtain a filter cake.

(5) Secondary oxidation: transferring the washed filter cake into a two-stage oxidation tank, and adding 300L of 35% hydrogen peroxide solution until the precipitate is completely dissolved to obtain blue copper sulfate solution;

(6) and (3) crystallization treatment: heating and evaporating a copper sulfate solution until a crystallization film appears on the surface, stopping heating, introducing into a crystallization reaction tank, slowly cooling to 25 ℃, cooling for crystallization, centrifugally filtering, and cleaning with a small amount of water or a saturated copper sulfate solution to obtain crystals, a filtrate and a mother solution;

(7) drying, and vacuum drying the crystal at 40 ℃ for 2h to obtain the high-purity copper sulfate product.

Example 2

The present embodiment is different from embodiment 1 in that: in the step (1), the ammonium chloride solution is 300L, the concentration is 15%, and the mass of the cuprous cyanide solid waste is 40 kg; 240L of sodium hydrosulfide solution in the step (3) with the mass fraction of 10 percent, and stirring for reaction for 60 min; slowly cooling the copper sulfate solution in the step (6) to 20 ℃; the drying temperature in the step (7) was 45 ℃.

Example 3

The present embodiment is different from embodiment 1 in that: adding 200L of copper precipitator in the step (3), and stirring and reacting for 60min by using 20% sodium sulfide solution; adding 340L of 35% hydrogen peroxide into the mixture to react in the step (5); the drying temperature in the step (7) is 45 ℃.

Example 4

The present embodiment is different from embodiment 1 in that: adding 300L of copper precipitator in the step (3) and 15% of sodium sulfide solution, and stirring for reacting for 60 min; adding 340L of 35% hydrogen peroxide into the mixture to react in the step (5); in the step (6), slowly cooling to 20 ℃, cooling and crystallizing; the drying temperature in the step (7) is 45 ℃.

Example 5

The present embodiment is different from embodiment 1 in that: adding 200L of copper precipitator, 20% of sodium sulfide solution, stirring and reacting for 60min, wherein the weak acid added is dilute sulfuric acid with the concentration of 10%; adding 340L of 35% hydrogen peroxide into the mixture to react in the step (5); the drying temperature in the step (7) is 40 ℃.

Example 6

The present embodiment is different from embodiment 1 in that: 300L of ammonium salt solution and 15% ammonium sulfate concentration in the step (1); adding 300L of copper precipitator in the step (3) and 15% of sodium sulfide solution, and stirring for reacting for 60 min; adding 340L of 35% hydrogen peroxide into the mixture to react in the step (5); in the step (6), slowly cooling to 20 ℃, cooling and crystallizing; the drying temperature in the step (7) is 40 ℃.

The amounts or concentrations of the key raw materials of examples 1-6 of the present invention are shown in the following table,

the copper sulfate product prepared by the process meets the execution standard of national standard GB 437-2009. The detection result of the copper sulfate product is as follows.

Copper sulfate detection is carried out according to GB437-2009 standard

Data for copper sulfate product testing in the examples

From the table, the copper sulfate product has water insoluble matter not more than 0.08 percent and acidity not more than 0.08 percent, meets the requirements of national standard GB437-2009 on water insoluble matter not more than 0.2 percent and acidity not more than 0.2 percent, has heavy metal total arsenic not more than 3.91mg/kg, total lead not more than 1.36mg/kg and total cadmium not more than 0.08mg/kg which are far lower than the national standard, and has CuSO in the recovered copper sulfate product₄·5H₂The content of O is more than or equal to 98 percent, and the content meets the national standard, so the nontoxic and high-purity copper sulfate product prepared by the process reaches the execution standard of the national standard GB 437-2009.

The foregoing examples are merely illustrative and serve to explain some of the features of the method of the present invention. The appended claims are intended to claim as broad a scope as is conceivable, and the examples presented herein demonstrate the results of applicants' actual experiments. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the invention. Also, where numerical ranges are used in the claims, subranges therein are included, and variations in these ranges are also to be construed as possible being covered by the appended claims.