A method for treating cyanide tailings using waste biomass

Abstract

This invention discloses a method for treating cyanide tailings using waste biomass: the cyanide tailings are crushed, then placed in a reaction vessel with biomass powder and an alkaline substance, and water is added. The mixture is heated to 200℃~350℃ for hydrothermal reaction. After the hydrothermal reaction, the mixture is filtered to obtain a sodium silicate solution and a solid filter. Hydrochloric acid is added to the sodium silicate solution for pH adjustment, then bone glue is added, and the mixture is heated and stirred, then filtered to obtain a sodium silicate solution and a desilication tailings liquid. The solid filter is enriched for gold using a carbon leaching method, followed by solid-liquid separation. The separated solid is then subjected to magnetic separation to obtain gold-loaded carbon and iron concentrate. This invention uses waste biomass as a reducing agent for cyanide tailings and employs a hydrothermal treatment method in an alkaline environment, which can greatly reduce the process cost during production. Furthermore, no harmful substances are generated during the reduction process, effectively protecting the environment; it also promotes the separation of valuable metals.

Description

Technical Field

[0001] This invention relates to the field of cyanide tailings treatment technology, and more particularly to a method for treating cyanide tailings using waste biomass. Background Technology

[0002] Cyanide gold extraction technology is currently the world's most important gold extraction technology due to its high recovery rate, simple process, wide application range, and low cost. However, processing gold concentrate using the cyanide method produces a large amount of cyanide tailings. Furthermore, because the valuable metals in the tailings are inhibited by cyanide, it is difficult to recover the minerals from the cyanide tailings, resulting in a large accumulation of insufficiently recovered cyanide tailings.

[0003] Cyanide tailings are rich in precious metals and large amounts of metals such as Fe, S, Si, and O, making them highly valuable for recycling. Currently, the main processes used for treating cyanide tailings include chlorination, flotation, and wet leaching. However, these methods suffer from problems such as severe pollution, limited application scope, and low recovery rates.

[0004] Patent CN202211119243.3 discloses a method for extracting valuable metals from cyanide tailings. This method employs a multi-stage melting oxidation and reduction smelting process to extract valuable resources from cyanide tailings while simultaneously recovering and treating the flue dust, achieving efficient treatment of the cyanide tailings. However, this method has a long overall process flow, complex steps, and high costs, making it difficult to effectively apply in actual production processes.

[0005] Patent CN202310013667.4 discloses a method for the comprehensive utilization of cyanide tailings. This method employs molten pool smelting technology, shortening the process flow and simultaneously converting iron oxide in the cyanide tailings into high-purity iron, thereby increasing the economic value of the product. However, this treatment technology requires electrolytic treatment of the cast iron plate, resulting in high overall energy consumption, high cost, and environmental pollution problems.

[0006] Patent CN202210180220.1 discloses a method for the harmless disposal of low-sulfur cyanide tailings through suspension oxidation roasting. This method effectively solves the problem of the difficulty in efficiently and completely oxidizing and decomposing complex cyanides at room temperature, and also reduces environmental pollution compared to traditional cyanide tailings treatment processes. However, this method also suffers from problems such as complex processes, high energy consumption, and high treatment costs, and is only applicable to cyanide tailings with low sulfur content.

[0007] The dissertation, "Study on the Transformation Behavior of Iron Minerals in the Starch Hydrothermal Processing of High-Iron Bauxite," proposed a method for treating high-iron bauxite using starch as a reducing agent via a high-temperature hydrothermal process. Starch promotes the reduction of ferric ions to ferrous ions, thereby achieving the separation of iron from the bauxite. However, this method only reduces the iron oxide component in high-iron bauxite, with limited effect on separating other components, and fails to achieve efficient resource utilization. Furthermore, this method is only suitable for ores with relatively simple compositions, such as high-iron bauxite, and is not applicable to the treatment of complex resources like cyanide tailings.

[0008] Patent CN202110236740.5 discloses a method for treating cyanide tailings, employing multiple washing, filtration, and drying processes to obtain a washing liquid rich in copper and cyanide. The washing liquid undergoes copper removal and membrane treatment, enabling efficient recovery of copper and cyanide ions from the cyanide tailings and simultaneously achieving green treatment of the tailings. However, this process consumes a large amount of water overall and has low recovery efficiency for rare and precious metals.

[0009] CN201410757942.4 discloses a method for the simultaneous reduction and recovery of gold and iron by chlorination roasting of cyanide tailings from gold concentrate. This method has a long production process, with chlorination roasting carried out at a high temperature of 1050℃, resulting in high energy consumption and severe equipment corrosion. Gold is easily lost during the chlorination volatilization process, and a large amount of impurity metals mix with gold chloride compounds, making subsequent gold purification difficult.

[0010] Patent CN104046783A discloses a method for recovering gold, silver, and lead from cyanide tailings. This method employs molten salt chlorination roasting, with a cyanide tailings to molten salt mass ratio of 1:0.5 to 1. The addition of a large amount of molten salt leads to an increase in the tailings volume. The chlorination roasting system causes severe equipment corrosion. While it achieves efficient gold volatilization, it struggles to achieve efficient gold recovery. This method primarily recovers gold, silver, and lead, without specifically targeting iron and silicon, and does not address the deep reduction and resource utilization of the tailings.

[0011] Patent CN202010473980.2 discloses a method for cyanide-breaking and iron extraction from ferrocyanide tailings via suspension magnetic roasting. This process involves crushing and grinding the ferrocyanide tailings, then placing them in a pre-oxidation suspension roasting furnace at 650-750℃ for cyanide-breaking roasting to obtain oxide slag powder. This oxide slag powder is then reduced and roasted, followed by two stages of grinding and magnetic separation to obtain iron concentrate. This process offers good production continuity and effective recovery of iron from ferrocyanide tailings. However, the overall energy consumption is high, and its application is limited, only suitable for cyanide tailings with high iron content. Furthermore, the phase control of iron oxides during reduction is difficult, and impurities in the magnetically separated iron concentrate easily exceed standards. This process does not recover gold or silver elements from the slag.

[0012] In summary, the currently disclosed methods for the resource utilization of cyanide tailings have not fundamentally solved the problems of high energy consumption, high cost, and low recovery rate of valuable components in pyrometallurgical or hydrometallurgical treatment methods for cyanide tailings. There is an urgent need for a treatment method that can achieve low-energy and low-cost treatment of cyanide tailings and efficient recovery of metal resources. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above and to provide a method for treating cyanide tailings using waste biomass.

[0014] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0015] A method for treating cyanide tailings using waste biomass includes the following steps:

[0016] (1) Crush the cyanide tailings, then place them in a reaction vessel with biomass powder and alkaline substances, add water, and heat to 200℃~350℃ for hydrothermal reaction treatment. After the hydrothermal reaction is completed, filter to obtain sodium silicate solution and solid filter material. The solid filter material is a mixture of high iron slag and activated carbon. At this temperature, the biomass material undergoes denaturation behavior in an alkaline environment, releasing atomic hydrogen to react with iron oxide to generate iron(III) oxide.

[0017] (2) Add hydrochloric acid to the sodium silicate solution obtained in step (1) to adjust the pH, then add bone glue, heat and stir, filter and separate to obtain sodium silicate solution and desilication tail liquid; the desilication tail liquid is returned to step (1) to replace alkaline substances for recycling;

[0018] (3) The solid filter material obtained in step (1) is enriched with gold by carbon leaching, and then the solid and liquid are separated. The separated solid is then separated by magnetic separation to obtain gold-loaded carbon and iron concentrate.

[0019] In step (1) of the present invention, the hydrothermal reaction may mainly occur in the following reaction equations, where R in the reaction equation is a collective term for the hydrocarbon chain, representing -[CH]- multi-chain.

[0020] RCN + NaOH + H2O → RCOONa + NH3;

[0021] RCHO+OH - →RCOO - +H·;

[0022] Fe 3+ +H·+OH - →Fe 2+ +H2O;

[0023] 2NaOH + SiO2 = Na2SiO3 + H2O;

[0024] 2NaOH+Al2O3+3H2O=2Na[Al(OH)4];

[0025] Na₂CO₃ + SiO₂ = Na₂SiO₃ + CO₂;

[0026] Na2CO3+Al2O3+4H2O=2Na[Al(OH)4]+CO2;

[0027] 2NaHCO3+SiO2=Na2SiO3+2CO2+H2O;

[0028] 2NaHCO3+Al2O3+3H2O=2Na[Al(OH)4]+2CO2.

[0029] In the above-described method for treating cyanide tailings using waste biomass, preferably, in step (1), the mass ratio of cyanide tailings to biomass powder is 9:1 to 1:1. The biomass content needs to be controlled within the range of this invention. If the biomass content is too low, the reduction effect on the cyanide tailings will be poor; if the biomass content is too high, it will be detrimental to the subsequent separation of various metal elements.

[0030] In the above-described method for treating cyanide tailings using waste biomass, preferably, in step (1), the mass ratio of biomass powder to alkaline substance is 19:1 to 5:1; the alkaline substance includes one or more of NaOH, Na2CO3, and NaHCO3. The content of alkaline substance needs to be controlled within the range of this invention. If the content of alkaline substance is too low, the effect will be poor, or even basically ineffective; if the content of alkaline substance is too high, it will excessively damage the carbon chain structure in the biomass material, making it difficult to effectively release atomic hydrogen.

[0031] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, in step (1), the solid-liquid ratio during the hydrothermal reaction is 1:3 to 1:8, with the ratio unit being g / mL.

[0032] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, the hydrothermal reaction time in step (1) is 1h to 12h.

[0033] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, the biomass material is one or more of the following: coconut shell, reed and other fruit shell biomass, straw biomass, and waste wood biomass.

[0034] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, in step (1), the particle size of the crushed cyanide tailings is 30-200 μm, and the particle size of the biomass material powder is 30-200 μm.

[0035] In the above-mentioned method of treating cyanide tailings using waste biomass, preferably, in step (2), hydrochloric acid is added to adjust the pH value to 8-10.

[0036] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, in step (2), the amount of bone glue added is 0.5-3 g / L, the heating and stirring temperature is 30-70℃, and the heating and stirring time is 0.5-3 h.

[0037] In the above-mentioned method of treating cyanide tailings using waste biomass, preferably, in step (3), the gold element enrichment is carried out by carbon leaching at least twice.

[0038] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, in step (3), the specific steps for enriching gold elements using the carbon leaching method are as follows: the solid filter material is placed in a reaction vessel, water and a leaching agent are added, and oxygen is introduced for leaching. The leaching agent is at least one of thiourea, thiosulfate, and halogen, and the mass addition amount of the leaching agent is 0.01-0.05% of the mass of the solid filter material. The oxygen introduction rate is 0.1 L / min-0.5 L / min, and the leaching time is 1 h-5 h. More preferably, the thiosulfate is selected from one or more of sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, and calcium thiosulfate, and the halogen is selected from one or more of iodine or bromine.

[0039] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, in step (3), the solid-liquid ratio during the carbon leaching process is 1:3 to 1:8.

[0040] In the above-mentioned method for treating cyanide tailings using waste biomass, preferably, the main components of the cyanide tailings include silicon dioxide: 14.2%–28.6%, ferric oxide: 20.8%–30.2%, aluminum oxide: 10.5%–12.6%, calcium silicate: 2.6%–4.0%, zinc sulfide: 10.7%–14.0%, and gold-containing mixture: 0.9%–3.5%.

[0041] The principle of this invention is as follows: Waste biomass materials are used as reducing agents for cyanide tailings. Under alkaline conditions and hydrothermal treatment at low temperatures below 350°C, efficient reduction of Fe2O3 in the cyanide tailings can be achieved. Simultaneously, the alkalinity causes silicon in the cyanide tailings to dissolve in the liquid as sodium silicate, effectively separating silicon and some aluminum, calcium, and other elements. Furthermore, cyanide ions in the cyanide tailings are converted to carboxyl groups under alkaline hydrothermal conditions, achieving harmless treatment of the tailings. During the hydrothermal treatment, the biomass powder gradually carbonizes by precisely controlling the reaction temperature. During carbonization, the carbon chains denature under alkaline conditions, releasing atomic hydrogen. The high pressure and temperature of the hydrothermal treatment further promote the release of atomic hydrogen. The released free atomic hydrogen acts as a reducing agent under the action of an alkaline catalyst, directionally reducing iron oxides to magnetite (Fe3O4). The biomass material, under the etching action of alkaline substances during carbonization, forms activated carbon with strong adsorption capacity. Then, bone glue was used to flocculate and enrich the sodium silicate solution, separating the sodium silicate solution and the desilication tailings. The carbon leaching method involves preliminary grinding and pulverization, which partially dissociates the gold into monomers. The high-iron slag enriched with gold and activated carbon is placed in a reactor, and by introducing oxygen and adding a small amount of leaching agent, the gold monomers are leached out. Simultaneously, the activated carbon material generated in the preceding process is used to enrich the gold, thus obtaining gold-loaded carbon.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) This invention uses waste biomass materials as reducing materials for cyanide tailings. Under alkaline conditions, hydrothermal treatment at low temperatures below 350°C can achieve efficient reduction of Fe2O3 in cyanide tailings. At the same time, the alkalinity causes silicon in the cyanide tailings to dissolve in the liquid as sodium silicate, achieving effective separation of silicon and some aluminum, calcium and other elements. This greatly reduces the process cost in the production process, and no harmful substances are generated during the reduction process, which can effectively protect the environment. Meanwhile, during the hydrothermal treatment, the biomass powder will gradually carbonize, and during the carbonization process, the carbon chain will undergo denaturation under alkaline conditions to release atomic hydrogen. At the same time, the high pressure and high temperature of hydrothermal treatment are more conducive to promoting the release of atomic hydrogen. The released free atomic hydrogen can act as a reducing agent under the action of an alkaline catalyst to directionally reduce iron oxide to iron(III) oxide, providing a basis for the subsequent separation of valuable metals.

[0044] (2) In this invention, bone glue is used to flocculate and enrich sodium silicate solution. The desilication tail liquid obtained after filtration, which contains a small amount of bone glue, is an alkaline solution and contains only trace amounts of sodium silicate. Since bone glue itself is mainly composed of carbon chain structure of C, H, N and O elements, it will decompose into multiple small carbon single chain structures under high temperature environment above 100°C. This carbon chain structure can also release atomic hydrogen under alkaline environment, promote the reduction of trivalent iron ions in cyanide tail residue, and has a synergistic treatment effect, realizing the recycling of desilication tail liquid.

[0045] (3) Based on existing biomass pyrolysis carbon materials, this invention uses carbon leaching to separate impurity elements in solid filter materials to obtain a mixture of high-purity iron concentrate and activated carbon materials. During the carbon leaching process, the activated carbon formed by the carbonization of biomass materials plays the main adsorption role, and there is no need to add additional activated carbon materials. After carbon leaching, magnetic separation is used to separate the iron concentrate, resulting in high-purity iron concentrate and gold-bearing carbon rich in gold elements. This achieves a high degree of enrichment of rare and precious metals and is also conducive to the subsequent extraction of rare and precious metal resources.

[0046] (4) This invention adds waste biomass materials to the cyanide tailings treatment process for hydrothermal treatment, realizing the recycling of waste biomass materials. At the same time, the cyanide ions in the cyanide tailings will be transformed into carboxyl groups under alkaline hydrothermal conditions, realizing the harmless treatment of the tailings. Attached Figure Description

[0047] Figure 1 This is a process flow diagram of the present invention for treating cyanide tailings using waste biomass. Detailed Implementation

[0048] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0049] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0050] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0051] In the following examples: the iron recovery rate is the total amount of iron in the finally separated iron(III) oxide divided by the iron content in the detected cyanide tailings; the gold recovery rate is the total amount of gold in the finally separated gold-loaded carbon divided by the gold content in the detected cyanide tailings.

[0052] Example 1:

[0053] A method for treating cyanide tailings using waste biomass according to the present invention is shown in the process flow diagram below. Figure 1 As shown, it includes the following steps:

[0054] (1) Cyanide tailings (containing 23.5% silicon dioxide, 24.3% iron oxide, 12.4% aluminum oxide, 3.2% calcium silicate, 12.3% zinc sulfide, and 3.2% gold-containing mixture) and waste reeds were crushed to 50 μm to obtain cyanide tailings powder and waste reed powder. Then, 800g of cyanide tailings powder and 200g of waste reed powder were mixed at a mass ratio of 4:1. 40g of NaOH was added to the mixture and stirred until homogeneous. The mixed material was placed in a hydrothermal reactor, and 8.32L of water was added to the reactor. The reactor was heated to 300℃ and held for 6 hours. After the holding period, it was allowed to cool naturally to room temperature. The reactor was then opened, and the reacted material was filtered to separate the liquid from the solid. The liquid was a sodium silicate solution, with a volume of approximately 8L. The solid was a mixture of high-iron slag and activated carbon, with a volume of approximately 436g.

[0055] (2) Add a small amount of hydrochloric acid to the 8L sodium silicate solution obtained by filtration to adjust the pH of the liquid to 8, then add 8g of bone glue to the liquid, turn on the stirring and heat to 50℃ and keep warm for 1h. After the reaction is completed, filter and separate to obtain 563g of sodium silicate solid with a purity of 49.62% and 7.8L of desiliconized tail liquid with a pH of 7.9 containing a small amount of bone glue. The desiliconized tail liquid can be recycled.

[0056] (3) Place the 436g high-iron slag and activated carbon mixture obtained in step (1) into a reactor, add 2.6L of water at a solid-liquid ratio of 1:6, add 0.02% thiourea, and leach oxygen at 0.2L / min for 2h. After leaching, separate the lean liquor and solid by filtration. Repeat the leaching of the lean liquor 4 times. Separate the iron concentrate from the final solid by magnetic separation. The magnetic separation magnetic field strength is 100kA / m. The remaining solid is gold-bearing carbon rich in gold. The grade of the separated iron concentrate is 75.87%, the iron recovery rate is 89.52%, and the gold recovery rate is 91.25%.

[0057] Example 2:

[0058] A method for treating cyanide tailings using waste biomass according to the present invention is shown in the process flow diagram below. Figure 1 As shown, it includes the following steps:

[0059] (1) Cyanide tailings (containing 24.3% iron oxide, 23.5% silicon dioxide, 12.4% aluminum oxide, 3.2% calcium silicate, 12.3% zinc sulfide, and 3.2% gold-containing mixture) and waste coconut shell material were crushed to 80μm respectively to obtain cyanide tailings powder and waste coconut shell powder. 900g of cyanide tailings powder and 300g of waste coconut shell powder were mixed in a 3:1 ratio, and then 30g of Na2CO3 was added and stirred to mix the mixture. The mixed material was placed in a hydrothermal reactor, and 4.92L of water was added to the hydrothermal reactor. The heating was turned on to raise the temperature of the hydrothermal reactor to 320℃ and hold for 3h. After the holding period, it was allowed to cool naturally. After cooling to room temperature, the hydrothermal reactor was opened, and the reacted material was filtered and separated to separate the liquid and solid. The liquid was a sodium silicate solution, about 4.9L; the solid was a mixture of high-iron slag and activated carbon, about 518g.

[0060] (2) Add a small amount of hydrochloric acid to the 4.9L sodium silicate solution obtained in step (1) to adjust the pH of the liquid to 10, then add 9.84g of bone glue to the liquid, start stirring and heat to 30℃ and keep warm for 3h. After the reaction is completed, filter and separate to obtain 695g of sodium silicate solid with a purity of 59.39% and 4.8L of desilication tail liquid with a pH of 9.5 containing a small amount of bone glue and recyclable.

[0061] (3) Place the 518g high-iron slag and activated carbon mixture obtained in step (1) into a reaction vessel, add 4.2L of water at a solid-liquid ratio of 1:8, add 0.04% thiourea, and leach oxygen at 0.3L / min for 1h. After leaching, separate the lean liquor and solid by filtration. Repeat the leaching of the lean liquor 3 times. For the solid that is finally separated, use weak magnetic separation to separate the iron concentrate. The magnetic field strength is 100kA / m. The remaining solid is gold-bearing carbon rich in gold. The grade of the separated iron concentrate is 71.24%, the iron recovery rate is 84.32%, and the gold recovery rate is 89.36%.

[0062] Example 3:

[0063] A method for treating cyanide tailings using waste biomass according to the present invention is shown in the process flow diagram below. Figure 1 As shown, it includes the following steps:

[0064] (1) Cyanide tailings (containing 24.3% iron oxide, 23.5% silicon dioxide, 12.4% aluminum oxide, 3.2% calcium silicate, 12.3% zinc sulfide, and 3.2% gold-containing mixture) and waste bamboo material were crushed to 40μm to obtain cyanide tailings powder and waste bamboo powder. 900g of cyanide tailings powder and 450g of waste bamboo powder were mixed in a 2:1 ratio, and then 90g of NaHCO3 was added and stirred until homogeneous. The mixed material was placed in a hydrothermal reactor, and 11.52L of water was added. The reactor was heated to 270℃ and held for 1 hour. After holding, it was allowed to cool naturally to room temperature. The reactor was then opened, and the reacted material was filtered to separate the liquid from the solid. The liquid was a sodium silicate solution, approximately 11.3L; the solid was a mixture of high-iron slag and activated carbon, approximately 684g.

[0065] (2) Add a small amount of hydrochloric acid to the 11.3L sodium silicate solution obtained by filtration to adjust the pH of the liquid to 10, then add 5.76g of bone glue to the liquid, turn on the stirring and heat to 40℃ and keep warm for 2h. After the reaction is completed, filter and separate to obtain 527g of sodium silicate solid with a purity of 53.41% and 11.1L of desilication tail liquid with a pH of 9.6 containing a small amount of bone glue and which can be recycled.

[0066] (3) 684g of high-iron slag and activated carbon mixture was placed in a reactor, 3.4L of water was added at a solid-liquid ratio of 1:5, 0.01% thiourea was added, and oxygen was introduced at 0.1L / min for leaching for 1h. After leaching, the lean liquor and solid were separated by filtration. The lean liquor was leached 4 times. The iron concentrate in the final separated solid was separated by weak magnetic separation with a magnetic field strength of 100kA / m. The remaining solid was gold-bearing carbon rich in gold. The grade of the separated iron concentrate was 69.85%, the iron recovery rate was 80.74%, and the gold recovery rate was 87.69%.

[0067] Comparative Example 1:

[0068] The comparative example uses pulverized coal as a reducing agent for cyanide tailings, and no alkaline substances are added during the hydrothermal process. The steps of this comparative example for treating cyanide tailings are as follows:

[0069] (1) Cyanide tailings (containing 23.5% silicon dioxide, 24.3% iron oxide, 12.4% aluminum oxide, 3.2% calcium silicate, 12.3% zinc sulfide and 3.2% gold-containing mixture) and coal powder were crushed to 50 μm respectively to obtain cyanide tailings powder and coal powder. Then, 800g of cyanide tailings powder and 200g of coal powder were mixed in a hydrothermal reactor at a mass ratio of 4:1. 8.32L of water was added to the hydrothermal reactor, without adding any alkaline substances. The heating was then turned on to raise the temperature of the hydrothermal reactor to 300℃ and held for 6 hours. After the holding period, it was allowed to cool naturally. After cooling to room temperature, the hydrothermal reactor was opened, and the reacted materials were filtered and separated to separate the liquid from the solid. The solid was a mixture of high-iron slag and coal powder, about 725g.

[0070] (2) Add a small amount of hydrochloric acid to the approximately 8L liquid obtained in step (1) to adjust the pH of the liquid to 8, then add 8g of bone glue to the liquid, turn on the stirring and heat to 50℃ and keep warm for 1h. After the reaction is completed, filter and separate the liquid to obtain 213g of sodium silicate solid with a purity of 25.3% and 8L of desilication tail liquid with pH=8 containing a large amount of bone glue.

[0071] (3) Place the 725g high-iron slag and coal powder mixture obtained in step (1) into a reactor, add 5.8L of water at a solid-liquid ratio of 1:8, add 0.02% thiourea, and leach oxygen at 0.2L / min for 2h. After leaching, separate the lean liquor and solid by filtration. Repeat the leaching of the lean liquor 4 times. Use a weak magnetic separation method with a magnetic field strength of 100kA / m to separate the iron concentrate from the final separated solid. The remaining solid is gold-bearing carbon rich in gold. The grade of the separated iron concentrate is 52.65%, the iron recovery rate is 62.19%, and the gold recovery rate is 43.00%.

Claims

1. A method for treating cyanide tailings using waste biomass, characterized in that, Includes the following steps: (1) Crush the cyanide tailings, then place them in a reaction vessel with biomass material powder and alkaline substances, add water, and heat to 200℃~350℃ for hydrothermal reaction treatment. After the hydrothermal reaction is completed, filter to obtain sodium silicate solution and solid filter material. The solid filter material is a mixture of high iron slag and activated carbon. (2) Add hydrochloric acid to the sodium silicate solution obtained in step (1) to adjust the pH, then add bone glue, heat and stir, filter and separate to obtain sodium silicate solution and desilication tail liquid; (3) The solid filter material obtained in step (1) is enriched with gold by carbon leaching, and then the solid and liquid are separated. The separated solid is then separated by magnetic separation to obtain gold-loaded carbon and iron concentrate.

2. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (1), the mass ratio of cyanide tailings to biomass powder is 9:1 to 1:

1.

3. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (1), the mass ratio of biomass material powder to alkaline substance is 19:1 to 5:1; the alkaline substance includes one or more of NaOH, Na2CO3, and NaHCO3.

4. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (1), during the hydrothermal reaction, the solid-liquid ratio is 1:3 to 1:8, and the unit of the ratio is g / mL.

5. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (1), the hydrothermal reaction takes 1 to 12 hours.

6. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (2), hydrochloric acid is added to adjust the pH value to 8-10.

7. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (2), the amount of bone glue added is 0.5-3 g / L, the heating and stirring temperature is 30-70℃, and the heating and stirring time is 0.5-3 h.

8. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (3), the gold element enrichment is carried out by carbon leaching at least twice.

9. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, In step (3), the specific steps for enriching gold elements using the carbon leaching method are as follows: the solid filter material is placed in a reaction vessel, water and leaching agent are added, and oxygen is introduced for leaching. The leaching agent is at least one of thiourea, thiosulfate, and halogen. The mass addition amount of the leaching agent accounts for 0.01 to 0.05% of the mass of the solid filter material. The oxygen introduction rate is 0.1 L / min to 0.5 L / min, and the leaching time is 1 h to 5 h.

10. The method for treating cyanide tailings using waste biomass as described in claim 1, characterized in that, The main components of the cyanide tailings include silicon dioxide: 14.2%–28.6%, ferric oxide: 20.8%–30.2%, aluminum oxide: 10.5%–12.6%, calcium silicate: 2.6%–4.0%, zinc sulfide: 10.7%–14.0%, and gold-containing mixture: 0.9%–3.5%.

Images