Method for decyanation of cyanidation tailings based on organic activated peroxide treatment

Abstract

The invention discloses a method for decyanation of cyanidation tailings based on organic activated peroxide.The method comprises the following steps that water is added into the cyanidation tailings to obtain ore pulp, the pH of the ore pulp is adjusted to be alkaline with sodium hydroxide, and cyanidation tailings adjusted ore pulp is obtained; an oxidizing agent and an organic activating agent are added into the cyanidation tailing adjusting ore pulp, a decyanation reaction is carried out, and a reaction material is obtained; and carrying out filter pressing and washing on the reaction materials to obtain filter residues and filtrate. According to the method, different types of organic activators are introduced and can react with hydrogen peroxide to generate different types of peroxy acids, the oxidation potential of the peroxy acids is higher than that of the hydrogen peroxide, so that the peroxy acids become a cyanide breaking agent with higher oxidation capacity than that of the hydrogen peroxide, and the problems that traditional hydrogen peroxide is not thorough in decyanation, low in decyanation efficiency and the like are solved. Meanwhile, the bleaching activation energy of peroxy acid is lower than that of hydrogen peroxide, and the bleaching temperature can be reduced to achieve the purpose of low-temperature cyanogen breaking.

Description

Technical Field

[0001] The invention belongs to the technical field of pollutant treatment, and in particular relates to a method for decyaniding cyanide tailings based on treating them with organic activated peroxides. Background Art

[0002] my country is a major gold producer, with over 95% of its gold produced using the cyanidation process. Cyanidation tailings are solid waste generated during the cyanidation gold extraction process. They contain characteristic pollutants such as cyanide, thiocyanate, and heavy metals, and are highly toxic, persistent, hidden, and difficult to handle. my country currently has nearly 1 billion tons of cyanidation tailings in stockpiles, with nearly 100 million tons generated annually. This massive amount of cyanidation tailings is mostly dumped in slag dumps for natural decyanation, which not only wastes precious resources but also poses significant environmental risks.

[0003] Currently, methods used both domestically and internationally to separate the harmful component cyanide from cyanide tailings include natural degradation (CN108246494A), chlorination (CN104070052A), incolysis (CN104261625A), biological (CN110813979A), high-temperature pyrolysis (CN112503547A), and chlorination volatilization (CN110438334A). Natural degradation, chlorination, incolysis, and chlorination volatilization pose secondary pollution risks, incomplete cyanide destruction, and health and safety hazards; biological methods require long processing times and are susceptible to environmental impacts; and high-temperature pyrolysis requires high process and equipment requirements, resulting in high processing costs. Therefore, there is an urgent need to develop new and effective technologies for treating cyanide tailings, with the goal of achieving industrial application and reducing or eliminating the environmental hazards posed by cyanide tailings. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a method for decyanation of cyanide tailings based on treating cyanide tailings with organic activated peroxides, thereby achieving harmless disposal of cyanide tailings and reducing the safety and environmental risks of cyanide tailings.

[0005] To achieve the above object, the present invention provides a method for decyaniding cyanide tailings based on treating them with organic activated peroxide, comprising the following steps:

[0006] adding water to the cyanide tailings to obtain a slurry, and adjusting the pH of the slurry to be alkaline with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0007] adding an oxidant and an organic activator to the cyanide tailings conditioned slurry to prepare a mixed slurry;

[0008] performing a decyanation reaction to obtain a reaction material;

[0009] The reaction material is subjected to filter pressing and washing to obtain a filter residue and a filtrate.

[0010] Furthermore, the mass concentration of the ore pulp is 20-50%.

[0011] Furthermore, the specific operation of adjusting the pH of the ore pulp to alkaline with sodium hydroxide is as follows: adjusting the pH of the ore pulp to 8.5-12.0 with sodium hydroxide.

[0012] Furthermore, the oxidant is selected from one of hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate and sodium persulfate; and the amount of the oxidant added to the mixed slurry is 5 to 40 g / L.

[0013] Furthermore, the oxidant is hydrogen peroxide; the amount of the oxidant added to the mixed slurry is 15-25 g / L, preferably 20 g / L.

[0014] Further, the organic activator is selected from one of urea, dicyandiamide, tetraacetylethylenediamine (TAED) and sodium nonanoyloxybenzenesulfonate (NOBS);

[0015] And / or, the addition amount of the organic activator accounts for 0.5-3% of the mass of the mixed slurry.

[0016] Furthermore, the organic activator is TAED or NOBS;

[0017] And / or, the addition amount of the organic activator accounts for 0.5-2% of the mass of the mixed slurry, preferably 2%.

[0018] The invention adopts an organic activator (including one of urea, dicyandiamide, tetraacetylethylenediamine (TAED) and sodium nonanoyloxybenzenesulfonate (NOBS)) to activate an oxidant (peroxides such as hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate and sodium persulfate), and uses the oxidant to oxidize, separate and remove poisonous components (cyanide and thiocyanate) in cyanide tailings generated in the gold industry, achieving a good removal effect.

[0019] Furthermore, the decyanation reaction is carried out at a temperature of 25 to 95° C. and for a time of 10 to 90 minutes.

[0020] Furthermore, the decyanation reaction temperature is 45 to 60° C., and the time is 20 to 50 minutes.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] To address the problems of high cyanide content, complex cyanide types, and difficulty in completely removing cyanide in cyanide tailings produced by gold mines, the present invention uses oxidizing bleaching agents used in the cleaning industry to quickly clean and separate cyanide and thiocyanide in cyanide tailings. By introducing different types of organic activators, they can react with hydrogen peroxide to produce different types of peroxyacids. The peroxyacids have a higher oxidation potential than hydrogen peroxide, making them a cyanide-breaking agent with stronger oxidizing power than hydrogen peroxide, solving the problems of incomplete decyanation and low decyanation efficiency of traditional hydrogen peroxide. At the same time, the bleaching activation energy of peroxyacids is lower than that of hydrogen peroxide, which can reduce the bleaching temperature to achieve the purpose of low-temperature cyanide breaking. The method of the present invention is simple and easy to operate, and has great prospects in the cleaning industry and gold smelting industry.

[0023] The present invention can be processed under normal pressure, eliminating the need for heavy metals or other ions to enter the system as catalysts or oxidants. The filtrate can be recycled as wash water for the cyanide tailings decyanation process, achieving comprehensive resource utilization. When the cyanide content is less than 0.5 mg / L, it meets national emission standards and can be discharged directly. The filter residue obtained after decyanation treatment can be dried and used for backfill treatment or secondary resource utilization. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] An embodiment of the present invention provides a method for decyaniding cyanide tailings by treating them with organic activated peroxide, comprising the following steps:

[0030] (1) adding water to the cyanide tailings to obtain a slurry, and adjusting the pH of the slurry to be alkaline with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0031] (2) adding an oxidant and an organic activator to the cyanide tailings conditioned slurry to prepare a mixed slurry;

[0032] (3) performing a decyanation reaction to obtain a reaction mass;

[0033] (4) The reaction material is subjected to filter pressing and washing to obtain filter residue and filtrate.

[0034] In an embodiment of the present invention, in step (1), the cyanidation tailings include conventional cyanidation tailings and oxidative cyanidation tailings. The oxidative cyanidation tailings include cyanidation tailings produced by biological pre-oxidation, pressure pre-oxidation, and roasting pre-oxidation. The solid components in the cyanidation tailings contain, by mass percentage, the following: Fe 15-50%, S 0.5-30%, SiO2 10-45%, Al2O3 1-10%, MgO 0.5-5%, CaO 0.5-5%, and the mass fraction of water is ≤20%.

[0035] In an embodiment of the present invention, in step (1), the mass concentration of the slurry is 20-50%.

[0036] In an embodiment of the present invention, in step (1), sodium hydroxide is used to adjust the pH of the slurry to 8.5-12.0.

[0037] In an embodiment of the present invention, in step (2), the oxidant is selected from one of hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate, and sodium persulfate; and the amount of the oxidant added to the mixed slurry is 5 to 40 g / L. Preferably, the oxidant is hydrogen peroxide; and the amount of the oxidant added to the mixed slurry is 15 to 25 g / L, more preferably 20 g / L.

[0038] In an embodiment of the present invention, the mass concentration of hydrogen peroxide is 30%.

[0039] In an embodiment of the present invention, in step (2), the organic activator is selected from one of urea, dicyandiamide, tetraacetylethylenediamine (TAED), and sodium nonanoyloxybenzenesulfonate (NOBS); the amount of the organic activator added is 0.5-3% by weight of the mixed slurry. Preferably, the organic activator is TAED or NOBS; the amount of the organic activator added is 0.5-2% by weight of the mixed slurry, preferably 1-2%, and more preferably 2%.

[0040] In the present invention, the oxidant can generate different types of peroxy acids with stronger oxidizing ability under the action of the organic activator.

[0041] In an embodiment of the present invention, in step (3), the decyanation reaction temperature is 25 to 95° C., and the time is 10 to 90 minutes. Preferably, the decyanation reaction temperature is 45 to 60° C., and the time is 20 to 50 minutes. The decyanation reaction is carried out under stirring at a stirring rate of 200 to 500 rpm.

[0042] In an embodiment of the present invention, in step (3), the chemical reaction equation involved in the decyanation process is:

[0043] H2O2+OH - →HOO - +H2O;

[0044] C 10 H 16 O4N2(TAED)+2H2O2→2CH3COOOH+C6H 12 N2O2;

[0045] C 15 H 21 O5SNa(NOBS)+HOO - →C8H 17 COOOH+C6H4SO3NaO - ;

[0046] CH3COOOH+CN - →CH3COOH+CNO - ;

[0047] C8H 17 COOOH+CN - →C8H 17 COOH+CNO - ;

[0048] 11CH3COOOH+2SCN - +2OH - →11CH3COOH+N2+2SO4 2- +2CO2+H2O;

[0049] 11C8H 17 COOOH+2SCN - +2OH - →11C8H 17 COOH+N2+2SO4 2- +2CO2+H2O.

[0050] After the oxidative decomposition and decyanation in step (3), the cyanide removal rate in the cyanide tailings is 92.6-99.6%, and the thiocyanate removal rate is 90.8-98.9%.

[0051] In an embodiment of the present invention, in step (4), the reaction material is filtered and washed using a filter press, and the filtrate is partially or completely returned to step (1) for slurry adjustment or directly discharged according to the situation (when the cyanide content in the filtrate is greater than 0.5 mg / L, it is recycled as washing water and returned to step (1) for slurry adjustment; when the cyanide content in the filtrate is ≤0.5 mg / L, it can be directly discharged); the filter cake produced after the filtration meets the processing requirements and is used for backfill treatment or resource secondary utilization.

[0052] In an embodiment of the present invention, the cyanide toxicity leaching content in the filter cake produced after filtration is no more than 5 mg / L, which complies with the standard HJ943-2018 "Technical Specifications for Cyanide Slag Pollution Control in the Gold Industry".

[0053] In the embodiment of the present invention, the cyanide tailings are conventional cyanide tailings and oxidative cyanide tailings produced in the cyanide gold extraction process.

[0054] In the embodiments of the present invention, the experimental water is all deionized water.

[0055] In an embodiment of the present invention, the pH value is adjusted by using a sulfuric acid solution or a sodium hydroxide solution.

[0056] In the examples of the present invention, the cyanide content was determined using the silver nitrate titration method specified in the national standard HJ 484-2009, "Water quality - Determination of cyanide - Volumetric and spectrophotometric method." The thiocyanate content was determined using the national standard GB / T 13897-92, "Water quality - Determination of thiocyanate - Isonicotinic acid-pyrazolone spectrophotometric method."

[0057] In an embodiment of the present invention, the filter residue is tested according to the test method of standard HJT299-2007 "Solid Waste Leaching Toxicity Leaching Method Sulfuric Acid and Nitric Acid Method" to obtain a toxic leachate, and the cyanide content thereof is ≤5mg / L and can be directly discharged.

[0058] In the embodiment of the present invention, the filter press needs to have the functions of squeezing, washing and air drying. According to the properties of different cyanide tailings, a certain amount of leaching agent sodium hydroxide can be added to the washing water, and the mass ratio of cyanide tailings to leaching agent is controlled at 50:1.

[0059] In the examples of the present invention, the hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate, sodium persulfate, urea, dicyandiamide, tetraacetylethylenediamine (TAED), sodium nonanoyloxybenzenesulfonate (NOBS), sulfuric acid, and sodium hydroxide used are all commercially available industrial products. The effective content of TAED and the effective content of NOBS are both ≥90%.

[0060] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0061] It should be pointed out that the matters not described in detail in the present invention are conventional operating methods in this field and are not the focus of the present invention. For example, the specific method of using a filter press for filtration and washing to obtain filter residue and filtrate is completed by conventional methods.

[0062] The technical solution of the present invention is further illustrated by the following examples.

[0063] Example 1

[0064] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0065] The cyanide tailings were conventional cyanide tailings produced by a gold enterprise in Fujian Province. After drying, the tailings contained Fe20.45%, S24.7%, SiO2 42.07%, Al2O3 10.13%, CaO 0.96%, ZnO 0.64%, and MgO 0.58%, with a cyanide content of 148 mg / L (toxic leaching) and a thiocyanate content of 1105 mg / L (toxic leaching).

[0066] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 25%, and the pH is adjusted to 12.0 with sodium hydroxide to prevent the generation of hydrogen cyanide gas to obtain a cyanide tailings adjusted slurry;

[0067] adding hydrogen peroxide (30% by mass, the same below) as an oxidant and tetraacetylethylenediamine (TAED) as an organic activator to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of hydrogen peroxide added to the mixed pulp is 20 g / L (i.e., the amount of hydrogen peroxide added is 20 g / L), and the amount of TAED added is 2% of the mass of the mixed pulp;

[0068] Decyanation reaction was carried out at a temperature of 55° C. and 300 rpm to remove cyanide and thiocyanide in the raw material. The reaction time was 30 min to obtain a reaction mass.

[0069] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0070] Testing showed that the removal rates of cyanide and thiocyanate were 99.2% and 97.6%, respectively. The cyanide content in the filtrate was 0.35 mg / L and could be discharged directly.

[0071] Example 2

[0072] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0073] The cyanidation tailings are the same as those in Example 1;

[0074] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 30%, and the pH is adjusted to 10.0 with sodium hydroxide to prevent the generation of hydrogen cyanide gas to obtain a cyanide tailings adjusted slurry;

[0075] Adding hydrogen peroxide as an oxidant and sodium nonanoyloxybenzenesulfonate (NOBS), an organic activator, to the cyanide tailings conditioned pulp to prepare a mixed pulp, wherein the amount of hydrogen peroxide added is 20 g / L and the amount of NOBS added is 2.5% of the mass of the mixed pulp;

[0076] Decyanation reaction was carried out at a temperature of 45° C. and 500 rpm to remove cyanide and thiocyanide in the raw material. The reaction time was 40 min to obtain a reaction mass.

[0077] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0078] Testing showed that the cyanide removal rate was 98.5%, the thiocyanate removal rate was 97.2%, and the cyanide content in the filtrate was 1.1 mg / L, which can be used as circulating water for slurry treatment.

[0079] Compared with the organic activator TAED in Example 1, the organic activator in Example 2 is NOBS. The amount of NOBS added in Example 2 is larger, the reaction time is longer, and the removal rate is slightly worse than that of TAED. Therefore, the removal effect of TAED is better than that of NOBS.

[0080] Example 3

[0081] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0082] The cyanide tailings were roasted oxidative cyanide tailings produced by a smelting company in Shandong. After drying, the tailings contained 46.36% Fe, 0.23% S, 28.14% SiO2, 5.8% Al2O3, 2.85% MgO, 1.66% ZnO, and 1.23% CaO by mass. The cyanide content was 206 mg / L (toxic leaching) and the thiocyanate content was 561 mg / L (toxic leaching).

[0083] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 30%, and the pH is adjusted to 10.5 with sodium hydroxide to prevent the generation of hydrogen cyanide gas to obtain a cyanide tailings adjusted slurry;

[0084] Adding hydrogen peroxide as an oxidant and NOBS as an organic activator to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of hydrogen peroxide added is 20 g / L, and the amount of NOBS added is 2% of the mass of the mixed pulp;

[0085] Decyanation reaction was carried out at a temperature of 75° C. and a stirring rate of 200 rpm to remove cyanide and thiocyanide in the raw material. The reaction time was 30 min to obtain a reaction mass.

[0086] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0087] Testing showed that the removal rates of cyanide and thiocyanate were 99.5% and 98.9%, respectively. The cyanide content in the filtrate was 0.27 mg / L and could be discharged directly.

[0088] Example 4

[0089] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0090] The cyanidation tailings are the same as those in Example 3;

[0091] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 20%, and the pH is adjusted to 11 with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0092] Adding an oxidizing agent, sodium percarbonate, and an organic activating agent, TAED, to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of sodium percarbonate solution added is 20 g / L, and the amount of tetraacetylethylenediamine added is 1.5% of the mass of the mixed pulp;

[0093] Decyanation reaction was carried out at a temperature of 65° C. to remove cyanide and thiocyanide in the raw material. The reaction time was 30 min to obtain a reaction material.

[0094] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0095] Testing showed that the removal rates of cyanide and thiocyanate were 98.2% and 96.8%, respectively. The cyanide content in the filtrate was 2.88 mg / L, suitable for use as circulating water for slurry treatment.

[0096] Example 5

[0097] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0098] The cyanidation tailings are the same as those in Example 1;

[0099] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 50%, and the pH is adjusted to 11 with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0100] Adding hydrogen peroxide as an oxidant and TAED as an organic activator to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of hydrogen peroxide added is 25 g / L, and the amount of tetraacetylethylenediamine added is 3% of the mass of the mixed pulp;

[0101] Decyanation reaction was carried out at 95°C and 300 rpm to remove cyanide and thiocyanide in the raw material for 10 min to obtain a reaction mass;

[0102] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0103] Testing showed that the removal rates of cyanide and thiocyanate were 99.6% and 97.7%, respectively. The cyanide content in the filtrate was 0.18 mg / L and could be discharged directly.

[0104] Example 6

[0105] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0106] The cyanidation tailings are the same as those in Example 1;

[0107] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 40%, and the pH is adjusted to 8.5 with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0108] Adding an oxidizing agent, sodium peroxide, and an organic activating agent, TAED, to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of sodium peroxide added is 40 g / L, and the amount of tetraacetylethylenediamine added is 0.5% of the mass of the mixed pulp;

[0109] Decyanation reaction was carried out at a temperature of 25° C. and 200 rpm to remove cyanide and thiocyanide in the raw material. The reaction time was 90 min to obtain a reaction mass.

[0110] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0111] Testing showed that the removal rates of cyanide and thiocyanate were 97.4% and 95.2%, respectively. The cyanide content in the filtrate was 2.5 mg / L, making it suitable for use as circulating water for slurry treatment.

[0112] Example 7

[0113] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides, comprising the following steps:

[0114] The cyanidation tailings are the same as those in Example 1;

[0115] The cyanide tailings are added with water to prepare a slurry with a mass concentration of 35%, and the pH is adjusted to 9.5 with sodium hydroxide to obtain a cyanide tailings adjusted slurry;

[0116] Adding an oxidizing agent, sodium persulfate, and an organic activating agent, NOBS, to the cyanide tailings conditioned pulp to prepare a mixed pulp; the amount of sodium persulfate added is 5 g / L, and the amount of tetraacetylethylenediamine added is 3% of the mass of the mixed pulp;

[0117] Decyanation reaction was carried out at 85°C and 200 rpm to remove cyanide and thiocyanide in the raw material for 50 min to obtain a reaction mass;

[0118] The reaction material is filtered and washed using a filter press to obtain a filter residue and a filtrate.

[0119] Testing showed that the removal rates of cyanide and thiocyanate were 95.1% and 92.8%, respectively. The cyanide content in the filtrate was 8.4 mg / L, suitable for use as circulating water for slurry treatment.

[0120] Example 8

[0121] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides is the same as that in Example 1, except that TAED is replaced by dicyandiamide, the amount of dicyandiamide added accounts for 1% of the mass of the mixed ore pulp, the decyaniding reaction temperature is 45° C., and the decyaniding reaction time is 50 min.

[0122] The removal rates of cyanide and thiocyanate were 92.6% and 90.8%, respectively. The cyanide content in the filtrate was 28.9 mg / L.

[0123] Example 9

[0124] A method for decyaniding cyanide tailings based on treating them with an organic activated peroxide is the same as that in Example 1, except that hydrogen peroxide is replaced by sodium perborate, the amount of sodium perborate added is 35 g / L, the temperature of the decyaniding reaction is 60° C., and the time of the decyaniding reaction is 80 min.

[0125] Testing showed that the removal rates of cyanide and thiocyanate were 98.3% and 96.8%, respectively. The cyanide content in the filtrate was 1.2 mg / L, suitable for use as circulating water for slurry treatment.

[0126] Example 10

[0127] A method for decyaniding cyanide tailings based on treating them with organic activated peroxides is the same as Example 2, except that the organic activator NOBS is replaced by urea, the amount of urea added is 3% of the mass of the mixed slurry, the decyaniding reaction temperature is 70° C., and the reaction time is 90 min.

[0128] Testing showed that the cyanide removal rate was 93.4%, the thiocyanate removal rate was 90.9%, and the cyanide content in the filtrate was 19.6 mg / L, which can be used as circulating water for slurry treatment.

[0129] Compared with the organic activator NOBS in Example 2, the organic activator in Example 10 is urea. It can be seen that when the reaction time is longer (90 min), the addition amount is larger (3%), and the reaction temperature is higher (70°C), the removal rate of urea is lower than that of NOBS at 40 min, 45°C, and 2.5% addition amount. Although the filtrate cannot be discharged directly, it can be used as circulating water for slurry treatment.

[0130] Comparative Example 1

[0131] Same as Example 1, except that TAED was not added.

[0132] The removal rates of cyanide and thiocyanate were 65.6% and 62.4%, respectively. The cyanide content in the filtrate was 77.6 mg / L.

[0133] In the method for decyanation of cyanide tailings in this comparative example, only an oxidant was added without an organic activator. The absence of an organic activator prevents the system from producing peroxyacids with stronger oxidizing power, and the system relies solely on the oxidizing property of hydrogen peroxide, resulting in a significant decrease in decyanation performance.

[0134] Comparative Example 2

[0135] Same as Example 1, except that no hydrogen peroxide was added.

[0136] The removal rate of cyanide was 2.4%, the removal rate of thiocyanate was 0.5%, and the cyanide content in the filtrate was 139 mg / L.

[0137] In the method for decyanation of cyanide tailings in this comparative example, only an organic activator is added without an oxidant, and the effective oxidizing substance peroxyacid cannot be generated, resulting in a significant decrease in the decyanation performance.

[0138] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for decyaniding cyanide tailings based on organic activated peroxide treatment, characterized in that: The following steps are involved: adding water to the cyanide tailings to obtain a slurry, and adjusting the pH of the slurry to be alkaline with sodium hydroxide to obtain a cyanide tailings adjusted slurry; adding an oxidant and an organic activator to the cyanide tailings conditioned slurry to prepare a mixed slurry; performing a decyanation reaction to obtain a reaction material; The reaction material is subjected to filter pressing and washing to obtain a filter residue and a filtrate.

2. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 1, wherein The mass concentration of the ore pulp is 20-50%.

3. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 1, wherein The pH value of the slurry is adjusted to 8.5-12.0 by the cyanide tailings.

4. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 1, wherein The oxidant is selected from one of hydrogen peroxide, sodium peroxide, sodium perborate, sodium percarbonate and sodium persulfate; And / or, the amount of the oxidant added to the mixed slurry is 5 to 40 g / L.

5. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 4, characterized in that, The oxidant is hydrogen peroxide; The amount of the oxidant added to the mixed slurry is 15-25 g / L.

6. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 1, characterized in that, The organic activator is selected from one of urea, dicyandiamide, tetraacetylethylenediamine and sodium nonanoyloxybenzenesulfonate; And / or, the addition amount of the organic activator accounts for 0.5-3% of the mass of the mixed slurry.

7. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 6, characterized in that: The organic activator is selected from one of tetraacetylethylenediamine and sodium nonanoyloxybenzenesulfonate; And / or, the addition amount of the organic activator accounts for 0.5-2% of the mass of the mixed slurry.

8. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 1, characterized in that, The temperature of the decyanation reaction is 25-95° C., and the time is 10-90 minutes.

9. The method for decyaniding cyanide tailings based on organic activated peroxide treatment according to claim 8, characterized in that: The temperature of the decyanation reaction is 45-60° C., and the time is 20-50 minutes.