Method for preparing mine filling gelling material using cyanide tailings

Abstract

The invention discloses a method for preparing a mine filling cementitious material by using cyanide tailings, comprising the following steps: weighing dried cyanide tailings, secondary aluminum ash, barium slag and phosphogypsum in proportion, and putting them into a tank mixer for mixing; after uniform mixing, adding sodium hydroxide solution for wetting, and using a tablet press to press the powder into a cubic green body, and placing the green body in an oven for drying without overlapping; putting the dried green body into a high-temperature box-type muffle furnace for calcining; adding phosphogypsum into the calcined clinker phase, crushing the green body, and sending the green body into a ball mill for ball milling treatment to obtain a cementitious material, and using tailings as aggregates, and supplemented with a polycarboxylic acid water reducer, and adding water to prepare a cementitious material for mine filling; the invention uses cyanide tailings as raw materials, and combines industrial solid wastes such as barium slag, secondary aluminum ash and phosphogypsum, and adopts a one-step activation method to prepare a cementitious material, which can simultaneously complete the decyanation and detoxification of the tailings and the activation of the tailings, has a simple process flow, and the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength.

Description

Technical Field

[0001] The invention relates to the field of comprehensive utilization of cyanide tailings, and in particular to a method for preparing a mine filling gelling material by utilizing cyanide tailings. Background Art

[0002] Cyanide tailings are solid waste generated during the cyanidation gold extraction process in the gold industry. They contain a certain amount of cyanide compounds and residual heavy metal elements such as copper, zinc, lead, and arsenic. If not handled properly, they will cause great harm to the environment. Currently, the treatment and disposal of cyanide tailings mainly includes two aspects: decyanation and detoxification and resource utilization.

[0003] The decyanation and detoxification treatment methods for cyanide tailings after gold extraction at home and abroad mainly include: activated carbon adsorption, acid volatilization, oxidation decomposition, natural degradation and microbial degradation. The above methods have different disadvantages: for example, the activated carbon adsorption method can only treat cyanide solutions with a pH greater than 1, and has high requirements for pH and high activated carbon treatment costs; the cyanide ion concentration after acid volatilization treatment is high and needs secondary treatment; the sulfur dioxide air method is not good for SCN - The removal rate is low, so the SCN - High-content cyanide tailings are difficult to treat effectively; HCN formed by natural degradation reactions easily enters the surrounding atmosphere; microbial treatment methods have certain limitations on their application due to factors such as complex cultivation of dominant strains, difficult to control treatment conditions, and complex equipment requirements.

[0004] The commonly used technologies for resource utilization of cyanide tailings after decyanation and detoxification are: mine backfilling, co-treatment with recycled cement kilns, recovery of valuable metal elements and utilization as building materials. Among them, mine backfilling has the advantages of on-site construction, large processing volume and low cost, and has become one of the most widely used technical means for cyanide tailings. However, cyanide tailings itself is an inert material with no gelling activity. When used for underground backfilling, a large amount of cement binder is often consumed. The disadvantages are also obvious: first, the resource and energy consumption is large, NO x First, the emission of atmospheric pollutants such as SO2 and particulate matter and CO2 is high; second, the cyanide tailings are fine in particles and high in mud content. When cement is used as a binder to prepare filling materials, there are problems such as low mechanical strength of the filling body and high cement consumption. Therefore, when cyanide tailings are used for filling cementitious materials, the difficulty lies in that it not only requires pretreatment of decyanation and detoxification, but also consumes a large amount of cement binder, and the above two processes often need to be carried out separately, which not only increases the complexity of the treatment process, but also increases the treatment cost. This is the main problem faced when cyanide tailings are used for underground filling. Summary of the invention

[0005] In order to solve the above technical problems, the present invention uses cyanide tailings as raw materials, combines industrial solid wastes such as barium slag, secondary aluminum ash and phosphogypsum, and adopts a one-step activation method to prepare a cementitious material for mine filling. The tailings decyanation and detoxification and tailings activation can be completed at the same time. The process flow is simple, and the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength.

[0006] The technical solution adopted by the present invention is: a method for preparing a mine filling gelling material using cyanide tailings, comprising the following steps:

[0007] S1. Batching: weigh the dried cyanide tailings, secondary aluminum ash, barium slag and phosphogypsum in proportion, put them into a tank mixer for mixing;

[0008] S2, preparation of drying material: after mixing evenly, add sodium hydroxide solution with a mass fraction of 1-6% to moisten, and use a tablet press to press the powder into a cubic body with a length, width and height of 2 cm respectively; place the pressed raw material in an oven without overlapping, and dry it at 60°C for 2-5 hours to obtain the drying material;

[0009] S3. Clinker preparation: Place the dried material into a high-temperature box-type muffle furnace for calcination. The calcination system is as follows:

[0010] The first stage: from room temperature to 400℃, the heating rate is 3℃ / min, and the holding time is 10-50min;

[0011] The second stage: from 400℃ to 1000℃, the heating rate is 5℃ / min, and the holding time is 10-30min;

[0012] The third stage: from 1000℃ to 1200℃, the heating rate is 5℃ / min;

[0013] The fourth stage: After the high-temperature calcination is completed, the cement clinker is quickly taken out from the muffle furnace and rapidly cooled with a fan at room temperature to increase the hydration activity of the cement clinker;

[0014] S4, preparation of a binder: adding phosphogypsum to the clinker phase obtained by calcination, crushing the mixture by a crusher, and then feeding the crushed mixture into a ball mill for ball milling to obtain a binder for filling cementitious materials;

[0015] S5. Preparation of cementitious materials: The binder prepared by the above process is used with tailings as aggregate and supplemented with polycarboxylic acid water reducer, and water is added to prepare the cementitious material for mine filling.

[0016] As a preferred solution, in step S1, the weight proportions of the raw material components are: 10-40 parts of cyanide tailings, 15-20 parts of secondary aluminum ash, 20-30 parts of barium slag, and 5-10 parts of phosphogypsum.

[0017] As a preferred embodiment, in step S3, the first stage drying material is subjected to a dehydration reaction, and the cyanide-containing heavy metal complex in the cyanide tailings is continuously decomposed and reacts with the remaining components in the drying material to decompose into non-toxic or low-toxic N2, NO x , CO2 and metal oxides:

[0018] CuCN+O2—→CuO+CO2+N2;

[0019] Zn(CN)2+O2—→ZnO+CO2+N2.

[0020] As a preferred solution, in step S3, the carbonate in the second stage drying material undergoes a decomposition reaction to create conditions for the subsequent synthesis of hydrated minerals at high temperature. At the same time, the metal elements and alkali metal elements in the drying material decompose the highly toxic soluble cyanide into non-toxic or low-toxic HCOO- and NH3:

[0021] NaCN+H2O→NaOH+HCN↑;

[0022] CN - +2H2O→HCOO - +NH3.

[0023] As a preferred embodiment, in step S3, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash in the third stage drying material undergo decomposition reactions and form SiO2, CaO, Al2O3, Fe2O3, BaO and SO3 oxides, and each oxide continuously reacts and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate.

[0024] As a preferred solution, in step S4, the amount of phosphogypsum added is 2-10% of the clinker phase.

[0025] As a preferred solution, in step S4, the specific surface area of ​​the powder after ball milling is 200 to 300 m 2 / kg.

[0026] As a preferred solution, in step S5, the total solid content of the cementitious material is 68-75%, and the mass ratio of the binder to the aggregate is 1:2-1:5.

[0027] As a preferred solution, in step S5, the compressive strengths of the mine filling cementitious material at 1d, 3d, 7d and 28d are 0.8-1.2 MPa, 2.2-3.6 MPa, 4.1-4.5 MPa and 5.2-5.6 MPa respectively.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention uses cyanide tailings as raw materials and jointly uses dangerous industrial solid wastes such as barium slag, secondary aluminum ash and phosphogypsum, wherein the main mineral components of the cyanide tailings are quartz, calcite and dolomite, the main mineral components of the barium slag are BaCO3, BaSO4 and aluminum silicon barium stone, the secondary aluminum ash mainly contains aluminum oxide, elemental aluminum, aluminum nitride and aluminum salt, and the main mineral component of the phosphogypsum is CaSO4; under high temperature conditions, the cyanide heavy metal complex contained in the cyanide tailings is relatively thoroughly decomposed into non-toxic or low-toxic N2, NO x , CO2 and metal oxides. The metal elements and alkali metal elements in the raw materials make the highly toxic soluble cyanide (CN-) decompose more thoroughly into non-toxic or low-toxic HCOO- and NH3; at the same time, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash will decompose and form oxides such as SiO2, CaO, Al2O3, Fe2O3, BaO and SO3. Each component reacts continuously and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate, so that the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength, and the activated cyanide slag can effectively replace cement for mine filling;

[0030] (2) The preparation process of the present invention adopts a one-step high-temperature activation method, which can simultaneously complete the decyanation and detoxification of tailings and the activation of tailings, avoiding the pretreatment process in the decyanation process of cyanide residues, effectively simplifying the process flow and reducing the preparation cost, integrating the decyanation and resource utilization of cyanide residues, and providing a low-cost and environmentally friendly technical approach for the safe disposal and resource utilization of cyanide residues. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution will be clearly and completely described in combination with the embodiments of the present invention. The solutions of the present invention are described in detail in combination with specific embodiments:

[0032] Example 1

[0033] The present invention uses cyanide tailings as raw materials, combines barium slag, secondary aluminum ash, phosphogypsum and other industrial solid wastes, adopts a one-step activation method to prepare a cementitious material for mine filling, can simultaneously complete the decyanation and detoxification of the tailings and the activation of the tailings, has a simple process flow, and the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength; specifically, the method for preparing a mine filling cementitious material using cyanide tailings includes the following steps:

[0034] S1. Ingredients: Dry various raw materials and weigh them in the following proportions: 10 parts of cyanide tailings, 20 parts of secondary aluminum ash, 30 parts of barium slag, and 5 parts of phosphogypsum. Put them into a tank mixer for mixing. During the mixing process, the stirring speed of the mixing blade is controlled to be 3m / s, and the mixing time is 3min.

[0035] The secondary aluminum ash in step S1 is industrial waste generated in the process of aluminum or aluminum alloy smelting and casting in the electrolytic aluminum, aluminum processing and recycled aluminum industries, and mainly contains aluminum oxide, elemental aluminum, aluminum nitride and aluminum salts, and also contains compounds of iron, calcium, magnesium and fluorine;

[0036] The barium slag in step S1 is a waste solid produced in the process of producing barium salt from barite, and its main components are barite, coal and barium salt that have not been completely burned;

[0037] The phosphogypsum described in step S1 is a solid waste generated in the wet phosphoric acid process, and its components are mainly calcium sulfate dihydrate, as well as incompletely decomposed phosphate rock, residual phosphoric acid, fluoride, acid insoluble matter, organic matter, etc.;

[0038] S2, preparation of drying material: after mixing evenly, add 1% sodium hydroxide solution by mass fraction for wetting, and use a tablet press to press the powder into a cubic body with a length, width and height of 2 cm respectively; place the pressed raw material in an oven without overlapping, and dry it at 60°C for 2 hours to obtain the drying material;

[0039] S3. Clinker preparation: Place the dried material into a high-temperature box-type muffle furnace for calcination. The calcination system is as follows:

[0040] The first stage: from room temperature to 400℃, the heating rate is 3℃ / min, and the holding time is 10min; in the first stage, the drying material undergoes a dehydration reaction, and the cyanide-containing heavy metal complex in the cyanide tailings continuously decomposes and reacts with the remaining components in the drying material to decompose into non-toxic or low-toxic N2 and NO x , CO2 and metal oxides:

[0041] CuCN+O2—→CuO+CO2+N2;

[0042] Zn(CN)2+O2—→ZnO+CO2+N2;

[0043] The second stage: from 400℃ to 1000℃, the heating rate is 5℃ / min, and the holding time is 10min; in the second stage, the carbonate in the drying material undergoes a decomposition reaction, creating conditions for the subsequent synthesis of hydrated minerals at high temperatures. At the same time, the metal elements and alkali metal elements in the drying material decompose the highly toxic soluble cyanide into non-toxic or low-toxic HCOO- and NH3:

[0044] NaCN+H2O→NaOH+HCN↑;

[0045] CN - +2H2O→HCOO - +NH3;

[0046] According to the flue gas detection at the furnace tail, the concentration of hydrogen cyanide in the exhaust gas is 0.07mg / m 3 , meet the relevant requirements of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996) and the "Occupational Exposure Limits for Hazardous Factors in the Workplace" (GBZ2.1-2007);

[0047] The third stage: from 1000℃ to 1200℃, the heating rate is 5℃ / min; in the third stage, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash in the drying material undergo decomposition reactions and form SiO2, CaO, Al2O3, Fe2O3, BaO and SO3 oxides, and each oxide continuously reacts and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate, so that the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength, and the activated cyanide slag can effectively replace cement for mine filling;

[0048] The fourth stage: After the high-temperature calcination is completed, the cement clinker is quickly taken out from the muffle furnace and rapidly cooled with a fan at room temperature to increase the hydration activity of the cement clinker;

[0049] S4. Preparation of binder: Add phosphogypsum to the clinker phase obtained by calcination, the amount of phosphogypsum added is 2% of the clinker phase, and crush it by a crusher. After crushing, it is sent to a ball mill for ball milling. The specific surface area of ​​the powder after ball milling is 200m 2 / kg, that is, the binder for filling cementitious materials is obtained;

[0050] S5. Preparation of cementitious materials: The binder prepared by the above process, with tailings as aggregate and supplemented with polycarboxylic acid water reducer, is prepared into a cementitious material for mine filling after adding water, wherein the total solid content of the cementitious material is 68%, and the mass ratio of the binder to the aggregate is 1:2.

[0051] Example 2

[0052] The present invention uses cyanide tailings as raw materials, combines barium slag, secondary aluminum ash, phosphogypsum and other industrial solid wastes, adopts a one-step activation method to prepare a cementitious material for mine filling, can simultaneously complete the decyanation and detoxification of the tailings and the activation of the tailings, has a simple process flow, and the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength; specifically, the method for preparing a mine filling cementitious material using cyanide tailings includes the following steps:

[0053] S1. Ingredients: Dry various raw materials and weigh them into the following proportions: 25 parts of cyanide tailings, 15 parts of secondary aluminum ash, 20 parts of barium slag, and 5 parts of phosphogypsum. Put them into a tank mixer for mixing. During the mixing process, the stirring speed of the mixing blade is controlled to be 15 m / s, and the mixing time is 10 min.

[0054] The secondary aluminum ash in step S1 is industrial waste generated in the process of aluminum or aluminum alloy smelting and casting in the electrolytic aluminum, aluminum processing and recycled aluminum industries, and mainly contains aluminum oxide, elemental aluminum, aluminum nitride and aluminum salts, and also contains compounds of iron, calcium, magnesium and fluorine;

[0055] The barium slag in step S1 is a waste solid produced in the process of producing barium salt from barite, and its main components are barite, coal and barium salt that have not been completely burned;

[0056] The phosphogypsum described in step S1 is a solid waste generated in the wet phosphoric acid process, and its components are mainly calcium sulfate dihydrate, as well as incompletely decomposed phosphate rock, residual phosphoric acid, fluoride, acid insoluble matter, organic matter, etc.;

[0057] S2, preparation of drying material: after mixing evenly, add sodium hydroxide solution with a mass fraction of 4% to moisten, and use a tablet press to press the powder into a cubic body with a length, width and height of 2 cm respectively; place the pressed raw material in an oven without overlapping, and dry it at 60°C for 4 hours to obtain the drying material;

[0058] S3. Clinker preparation: Place the dried material into a high-temperature box-type muffle furnace for calcination. The calcination system is as follows:

[0059] The first stage: from room temperature to 400℃, the heating rate is 3℃ / min, and the holding time is 30min; in the first stage, the drying material undergoes a dehydration reaction, and the cyanide-containing heavy metal complex in the cyanide tailings continuously decomposes and reacts with the remaining components in the drying material to decompose into non-toxic or low-toxic N2 and NO x , CO2 and metal oxides:

[0060] CuCN+O2—→CuO+CO2+N2;

[0061] Zn(CN)2+O2—→ZnO+CO2+N2;

[0062] The second stage: from 400℃ to 1000℃, the heating rate is 5℃ / min, and the holding time is 20min; in the second stage, the carbonate in the drying material undergoes a decomposition reaction, creating conditions for the subsequent synthesis of hydrated minerals at high temperatures. At the same time, the metal elements and alkali metal elements in the drying material decompose the highly toxic soluble cyanide into non-toxic or low-toxic HCOO- and NH3:

[0063] NaCN+H2O→NaOH+HCN↑;

[0064] CN - +2H2O→HCOO - +NH3;

[0065] According to the flue gas detection at the furnace tail, the concentration of hydrogen cyanide in the exhaust gas is 0.07mg / m 3 , meet the relevant requirements of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996) and the "Occupational Exposure Limits for Hazardous Factors in the Workplace" (GBZ2.1-2007);

[0066] The third stage: from 1000℃ to 1200℃, the heating rate is 5℃ / min; in the third stage, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash in the drying material undergo decomposition reactions and form SiO2, CaO, Al2O3, Fe2O3, BaO and SO3 oxides, and each oxide continuously reacts and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate, so that the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength, and the activated cyanide slag can effectively replace cement for mine filling;

[0067] The fourth stage: After the high-temperature calcination is completed, the cement clinker is quickly taken out from the muffle furnace and rapidly cooled with a fan at room temperature to increase the hydration activity of the cement clinker;

[0068] S4. Preparation of binder: Add phosphogypsum to the clinker phase obtained by calcination, the amount of phosphogypsum added is 6% of the clinker phase, and crush it by a crusher. After crushing, it is sent to a ball mill for ball milling. The specific surface area of ​​the powder after ball milling is 250m 2 / kg, that is, the binder for filling cementitious materials is obtained;

[0069] S5. Preparation of cementitious materials: The binder prepared by the above process, with tailings as aggregate and supplemented with polycarboxylic acid water reducer, is prepared into a cementitious material for mine filling after adding water, wherein the total solid content of the cementitious material is 72%, and the mass ratio of the binder to the aggregate is 1:3.

[0070] Example 3

[0071] The present invention uses cyanide tailings as raw materials, combines barium slag, secondary aluminum ash, phosphogypsum and other industrial solid wastes, adopts a one-step activation method to prepare a cementitious material for mine filling, can simultaneously complete the decyanation and detoxification of the tailings and the activation of the tailings, has a simple process flow, and the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength; specifically, the method for preparing a mine filling cementitious material using cyanide tailings includes the following steps:

[0072] S1. Ingredients: Dry various raw materials and weigh them into the following proportions: 40 parts of cyanide tailings, 15 parts of secondary aluminum ash, 20 parts of barium slag, and 8 parts of phosphogypsum. Put them into a tank mixer for mixing. During the mixing process, the stirring speed of the mixing blade is controlled to be 20 m / s, and the mixing time is 15 min.

[0073] The secondary aluminum ash in step S1 is industrial waste generated in the process of aluminum or aluminum alloy smelting and casting in the electrolytic aluminum, aluminum processing and recycled aluminum industries, and mainly contains aluminum oxide, elemental aluminum, aluminum nitride and aluminum salts, and also contains compounds of iron, calcium, magnesium and fluorine;

[0074] The barium slag in step S1 is a waste solid produced in the process of producing barium salt from barite, and its main components are barite, coal and barium salt that have not been completely burned;

[0075] The phosphogypsum described in step S1 is a solid waste generated in the wet phosphoric acid process, and its components are mainly calcium sulfate dihydrate, as well as incompletely decomposed phosphate rock, residual phosphoric acid, fluoride, acid insoluble matter, organic matter, etc.;

[0076] S2, preparation of drying material: after mixing evenly, add 6% by mass sodium hydroxide solution for wetting, and use a tablet press to press the powder into a cubic body with a length, width and height of 2 cm respectively; place the pressed raw material in an oven without overlapping, and dry it at 60°C for 5 hours to obtain the drying material;

[0077] S3. Clinker preparation: Place the dried material into a high-temperature box-type muffle furnace for calcination. The calcination system is as follows:

[0078] The first stage: from room temperature to 400℃, the heating rate is 3℃ / min, and the holding time is 50min; in the first stage, the dried material undergoes a dehydration reaction, and the cyanide-containing heavy metal complex in the cyanide tailings continuously decomposes and reacts with the remaining components in the dried material to decompose into non-toxic or low-toxic N2 and NO x , CO2 and metal oxides:

[0079] CuCN+O2—→CuO+CO2+N2;

[0080] Zn(CN)2+O2—→ZnO+CO2+N2;

[0081] The second stage: from 400℃ to 1000℃, the heating rate is 5℃ / min, and the holding time is 30min; in the second stage, the carbonate in the drying material undergoes a decomposition reaction, creating conditions for the subsequent synthesis of hydrated minerals at high temperatures. At the same time, the metal elements and alkali metal elements in the drying material decompose the highly toxic soluble cyanide into non-toxic or low-toxic HCOO- and NH3:

[0082] NaCN+H2O→NaOH+HCN↑;

[0083] CN - +2H2O→HCOO - +NH3;

[0084] According to the flue gas detection at the furnace tail, the concentration of hydrogen cyanide in the exhaust gas is 0.07mg / m 3 , meet the relevant requirements of the "Integrated Emission Standard of Air Pollutants" (GB16297-1996) and the "Occupational Exposure Limits for Hazardous Factors in the Workplace" (GBZ2.1-2007);

[0085] The third stage: from 1000℃ to 1200℃, the heating rate is 5℃ / min; in the third stage, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash in the drying material undergo decomposition reactions and form SiO2, CaO, Al2O3, Fe2O3, BaO and SO3 oxides, and each oxide continuously reacts and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate, so that the prepared filling material has a fast hydration and hardening rate, good fluidity and high mechanical strength, and the activated cyanide slag can effectively replace cement for mine filling;

[0086] The fourth stage: After the high-temperature calcination is completed, the cement clinker is quickly taken out from the muffle furnace and rapidly cooled with a fan at room temperature to increase the hydration activity of the cement clinker;

[0087] S4. Preparation of binder: Add phosphogypsum to the clinker phase obtained by calcination, the amount of phosphogypsum added is 10% of the clinker phase, and crush it by a crusher. After crushing, it is sent to a ball mill for ball milling. The specific surface area of ​​the powder after ball milling is 300m 2 / kg, that is, the binder for filling cementitious materials is obtained;

[0088] S5. Preparation of cementitious materials: The binder prepared by the above process, with tailings as aggregate and supplemented with polycarboxylic acid water reducer, is prepared into a cementitious material for mine filling after adding water, wherein the total solid content of the cementitious material is 75%, and the mass ratio of the binder to the aggregate is 1:5.

[0089] According to the test method specified in the Technical Standard for Metal and Non-metal Mine Filling Engineering (GB / T51450-2022), the prepared mine filling cementitious materials in Examples 1 to 3 were tested:

[0090]

[0091] According to the method specified in "Horizontal Oscillation Method for Leaching Toxicity of Solid Waste" HJ557-2009, the filling body in Example 3 that was hydrated for 28 days was sampled, crushed and passed through a 3mm sieve, 100g of the sieved sample was taken, dried to constant weight at 105°C, 1L of distilled water was added at a liquid-to-solid ratio of 10:1 (L / kg), the oscillation frequency was controlled to 110 times / min, horizontal oscillation was performed, oscillated for 8 hours, allowed to stand for 16 hours, filtered, and the filtrate was collected for leaching toxicity analysis; the analysis results showed that:

[0092] The concentration of easily releasable cyanide in the leachate is 0.014 mg / L, which is far lower than the control index of "Technical Specifications for Cyanide Slag Pollution in the Gold Industry" HJ943-2018; the contents of heavy metals such as total copper, total lead, total mercury, total arsenic, hexavalent chromium, and total cadmium in the leachate are all far lower than the relevant standard requirements of the "Groundwater Quality Standard" (GB / T14848).

[0093] In summary, the preparation process of the present invention adopts a one-step high-temperature activation method, which can simultaneously complete the decyanation and detoxification of tailings and tailings activation, avoid the pretreatment process in the decyanation process of cyanide residues, effectively simplify the process flow, reduce the preparation cost, and integrate the decyanation and resource utilization of cyanide residues, thereby providing a low-cost and environmentally friendly technical approach for the safe disposal and resource utilization of cyanide residues.

[0094] In addition, the above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a mine filling gelling material using cyanide tailings, characterized in that: The following steps are involved: S1. Ingredients: weigh the dried cyanide tailings, secondary aluminum ash, barium slag and phosphogypsum in proportion, put them into a tank mixer for mixing; wherein the weight proportions of each raw material component are: 10-40 parts of cyanide tailings, 15-20 parts of secondary aluminum ash, 20-30 parts of barium slag, and 5-10 parts of phosphogypsum; S2. Preparation of dried material: After mixing evenly, add 1-6% sodium hydroxide solution by mass to moisten it, and use a tablet press to press the powder into a cubic body with a length, width and height of 2 cm respectively; place the pressed raw material in an oven without overlapping, and dry it at 60°C for 2-5 hours to obtain the dried material; S3. Clinker preparation: Place the dried material into a high-temperature box-type muffle furnace for calcination. The calcination system is as follows: The first stage: from room temperature to 400℃, the heating rate is 3℃ / min, and the holding time is 10~50min; The second stage: from 400℃ to 1000℃, the heating rate is 5℃ / min, and the holding time is 10~30min; The third stage: from 1000℃ to 1200℃, the heating rate is 5℃ / min; The fourth stage: After the high-temperature calcination is completed, the cement clinker is quickly taken out from the muffle furnace and rapidly cooled with a fan at room temperature to increase the hydration activity of the cement clinker; S4, preparation of a binder: adding phosphogypsum to the clinker phase obtained by calcination, crushing the mixture by a crusher, and then feeding the crushed mixture into a ball mill for ball milling to obtain a binder for filling cementitious materials; S5. Preparation of cementitious materials: The binder prepared by the above process, with tailings as aggregate and supplemented with polycarboxylic acid water reducer, is prepared into cementitious materials for mine filling after adding water.

2. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S3, the first stage drying material is subjected to a dehydration reaction, and the cyanide-containing heavy metal complex in the cyanide tailings is continuously decomposed and reacts with the remaining components in the drying material to decompose into non-toxic or low-toxic N2, NO x , CO2 and metal oxides: CuCN+O2—→CuO+CO2+N2; Zn(CN)2+O2—→ZnO+CO2+N2.

3. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S3, the carbonate in the second stage drying material undergoes a decomposition reaction, creating conditions for the subsequent synthesis of hydrated minerals at high temperature. At the same time, the metal elements and alkali metal elements in the drying material decompose the highly toxic soluble cyanide into non-toxic or low-toxic HCOO- and NH3: NaCN+H2O→NaOH+HCN↑; CN - +2H2O→HCOO - +NH3 4. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S3, the main minerals in the cyanide tailings, barium slag, phosphogypsum and secondary aluminum ash in the third stage drying material undergo decomposition reactions and form SiO2, CaO, Al2O3, Fe2O3, BaO and SO3 oxides, and each oxide continuously reacts and continuously forms a clinker phase containing barium sulfoaluminate, dicalcium silicate and calcium ferroaluminate.

5. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S4, the amount of phosphogypsum added is 2-10% of the clinker phase.

6. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S4, the specific surface area of ​​the powder after ball milling is 200-300m 2 / kg.

7. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S5, the total solid content of the cementitious material is 68-75%, and the mass ratio of the binder to the aggregate is 1:2-1:

5.

8. The method for preparing a mine filling gelling material using cyanide tailings according to claim 1, characterized in that: In step S5, the compressive strengths of the mine filling cementitious material at 1d, 3d, 7d and 28d are 0.8-1.2 MPa, 2.2-3.6 MPa, 4.1-4.5 MPa and 5.2-5.6 MPa respectively.

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