A method for recycling and harmless treatment of gold cyanidation tailings

Abstract

A kind of gold cyanidation tailings resource and harmless treatment method, belong to mineral processing technical field, including steps (1) the cyanide tailings of gold smelting enterprise cyanidation leaching process gold extraction after pressure filtration dehydration;(2) the cyanide tailings after dehydration into to suspension furnace and carry out preheating dehydration, toxic and harmful substances in tailings are destroyed at high temperature oxidation, pyrolysis, cyanide tailings can remove all or part of the attached water after this process;(3) the cyanide tailings after preheating roasting treatment enter the inside of reactor and carry out oxidation roasting, get de-cyanation tailings after oxidation roasting treatment;(4) the de-cyanation tailings after cooling enter electric furnace smelting, this process further smelt de-cyanation tailings into water slag and pig iron, water slag can be used as building material and cement after treatment, pig iron can be used for steelmaking cast iron after treatment.The cyanide is not detected in cyanide tailings after the method of the application, and the gold tailings resource and harmless are truly realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mineral processing, and particularly relates to a treatment, resource utilization and harmless utilization method of gold cyanide tailings. BACKGROUND

[0002] The traditional disposal method of cyanide tailings is to directly store in the surface empty land or directly fill in the depression, and in the two methods, the cyanide tailings still contact with rainwater and air in the environment, and the toxic and harmful substances can affect the environment through various channels.

[0003] Cyanide in cyanide tailings exists in the form of complex ions, and is unstable in the environment. When reacting with acid and alkali, hydrogen cyanide and cyanide salt are generated. Inorganic cyanide is highly toxic and can rapidly release cyanide ions in the body to cause acute poisoning and even death, and can also cause crop yield reduction.

[0004] Heavy metal ions in the tailings can be gradually released for a long time, such as toxic substances like cadmium. After the release of heavy metals, groundwater and soil will be polluted, and the pollution is difficult to solve once it occurs, which is very harmful.

[0005] The residual flotation reagents contained in the tailings also have certain toxicity. The simple storage and landfill of cyanide tailings will cause great harm to the environment.

[0006] At present, most of the cyanide tailings generated in the gold industry are still stored in the tailings pond, and a small part is treated again due to containing valuable elements for recycling, but the transportation operation in the treatment process needs to be strictly in accordance with the transportation specification of national hazardous waste, which has high risk.

[0007] Therefore, the resource utilization and harmless treatment of gold cyanide tailings has become a major research topic faced by the gold industry. SUMMARY

[0008] In view of the above problems, the purpose of the present application is to provide a resource utilization and harmless treatment method of gold cyanide tailings.

[0009] The following technical scheme is adopted, and the specific content is as follows:

[0010] (1) Raw material treatment: the cyanide tailings after gold extraction by cyanide leaching process of gold smelting enterprises are subjected to pressure filtration to reduce the attached water to 15% or less;

[0011] (2) Preheating roasting: cyanide tailings containing 15% and below attached water into the suspension furnace for preheating dehydration, toxic and harmful substances in the tailings are destroyed by oxidation and pyrolysis at high temperature, the preheating temperature is maintained at 800-1000℃, the flue gas is taken away along with the negative pressure path, the system negative pressure control range is-1~-10KPa, the cyanide tailings can remove all or part of the attached water after this process;

[0012] (3) Oxidation roasting: the cyanide tailings after preheating roasting treatment enter the reactor for oxidation roasting, which is the most critical step of breaking cyanide, the reactor internal control temperature range is 500-800℃, the residence time of cyanide tailings in the reactor is 10min-2h, oxygen needs to be continuously introduced during the oxidation roasting process, and the decyanation tailings are obtained after the oxidation roasting treatment;

[0013] (4) Electric furnace smelting: the cooled decyanation tailings enter the electric furnace for smelting, the temperature range of the electric furnace smelting pool is 1000-1500℃, the flue gas is taken away along with the negative pressure path, and the control range of the negative pressure is-1~-10KPa, which further smelts the decyanation tailings into water slag and pig iron, the water slag can be used as building materials and cement after treatment, and the pig iron can be used for steelmaking and cast iron after treatment. The water slag obtained by the method meets the national standard of 《GBN 164-1982》, and can be used as admixture in concrete at a mixing ratio of about 7-8%.

[0014] The above-mentioned resource utilization and harmless treatment method of gold cyanide tailings, wherein:

[0015] In the step (2), the required preheating temperature is preferably 900-950℃.

[0016] In the step (2), the required negative pressure range is preferably-1~-5KPa.

[0017] In the step (3), the oxidation roasting temperature is preferably 600-650℃.

[0018] In the step (3), the oxidation roasting time is preferably 10min-1h.

[0019] In the step (3), the total cyanide content in the decyanation tailings is below 0.04mg / kg; the tail gas finally becomes CO2.

[0020] In the steps (1)-(4), the following chemical reactions are included:

[0021] 4FeS2+11O2=2Fe2O3+8SO2

[0022] Fe2O3+1 / 3C=2 / 3Fe3O4+1 / 3CO↑

[0023] Fe3O4 + C = 3FeO + CO↑

[0024] FeO + C = Fe + CO↑

[0025] FeO + CO = Fe + CO2

[0026] In the step (4), the temperature of the electric furnace bath is preferably 1200-1500 DEG C; the water slag has poor flowability and the reducing atmosphere is poor when the temperature is lower than 1200 DEG C, and the refractory in the furnace is seriously damaged when the temperature exceeds 1500 DEG C or the temperature is too high.

[0027] In the step (4), the control negative pressure range is preferably-1~-5KPa.

[0028] In the method, the smoke dust in the direct exhaust flue gas can reach 10mg / Nm 3 The following ultra-low emission index. According to "cement industry air pollutants ultra-low emission standard" implementation.

[0029] After the method of the application, the cyanide in the gold cyanide tailings can be fully broken, and the de-cyanide tailings obtained by treatment do not belong to dangerous waste, and the harm of cyanide tailings to the environment is eliminated. And the de-cyanide tailings can be truly realized by using electric furnace smelting.

[0030] The treatment process of the gold cyanide tailings of the application is as shown in Figure 1 The raw materials are preheated after dehydration treatment, then enter the oxidation roasting for cyanide breaking treatment, and finally enter the electric furnace for smelting to obtain the target product.

[0031] Compared with the prior art, the application has the following advantages:

[0032] (1) The prior art can only reduce the cyanide content to 5mg / kg, while the cyanide content in the cyanide tailings treated by the method of the application is not detected, so that the gold tailings are truly realized resource utilization and harmlessness;

[0033] (2) High degree of automation. The whole system adopts distributed control system, saves manpower, and the operation is simple. The raw materials do not need special treatment and can be directly put into the furnace;

[0034] (3) There is no risk of leakage in the treatment system, and there is no toxic substance volatilization in the process, and the production environment is safe and controllable;

[0035] (4) According to the method of the application, the total cyanide content in the de-cyanide tailings is less than 0.04mg / kg, and the cyanide tailings treated by oxidation roasting and electric furnace smelting can be used as high-quality raw materials for cement plants and steelmaking and iron casting. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1A process flow chart of the gold cyanidation tailings treatment method of the present application. DETAILED DESCRIPTION

[0037] The gold cyanidation tailings used in the embodiments of the present application are from a gold smelting enterprise in Laizhou City, Shandong Province, and the main components of the tailings are TFe, CaO, Au, and MgO.

[0038] The suspension furnace used in the embodiments of the present application refers to the iron ore smelting method and device based on the direct connection of the suspension roasting furnace and the smelting reduction furnace (CN114015866A).

[0039] Embodiment 1

[0040] A resource utilization and harmless treatment method of gold cyanidation tailings, as Figure 1 described, the specific operation steps are:

[0041] (1) Raw material treatment: the cyanidation tailings after gold extraction by cyanidation leaching process of a gold smelting enterprise are subjected to pressure filtration by a filter press to reduce the attached water therein to 15%;

[0042] (2) Preheating roasting: the cyanidation tailings containing 15% attached water are subjected to preheating and dehydration in a suspension furnace, the toxic and harmful substances in the tailings are destroyed by oxidation and pyrolysis at high temperature, the preheating temperature is maintained at 800°C, the flue gas is taken away along the negative pressure path, and the system negative pressure control range is-2KPa, and the cyanidation tailings can remove all or part of the attached water after this process;

[0043] (3) Oxidation roasting: the cyanidation tailings after preheating roasting treatment are subjected to oxidation roasting in the reactor, which is the most critical step of cyanide destruction, the temperature in the reactor is controlled in the range of 500°C, the residence time of the cyanidation tailings in the reactor is in the range of 10min, and oxygen is continuously supplied during the oxidation roasting process, and the decyanation tailings are obtained after the oxidation roasting treatment;

[0044] (4) Electric furnace smelting: the cooled decyanation tailings are subjected to electric furnace smelting, the temperature of the electric furnace bath is in the range of 1000°C, the flue gas is taken away along the negative pressure path, and the negative pressure control range is-2KPa, and the decyanation tailings are further smelted into water slag and pig iron in this process, the water slag after treatment reaches the national standard of GBN 164-1982 and can be used as building materials and cement, and the pig iron after treatment can be used for steelmaking and cast iron.

[0045] Embodiment 2

[0046] A resource utilization and harmless treatment method of gold cyanidation tailings, as Figure 1 described, the specific operation steps are:

[0047] (1) Raw material treatment: the cyanide tailings after gold extraction by cyanide leaching process in gold smelting enterprises are filtered by a filter press to reduce the attached water to 15%;

[0048] (2) Preheating roasting: the cyanide tailings containing 15% attached water are fed into a suspension furnace for preheating and dehydration, the toxic and harmful substances in the tailings are destroyed by oxidation and pyrolysis at high temperature, the preheating temperature is kept at 900℃, the flue gas is taken away along the negative pressure path, the system negative pressure control range is-2.2KPa, and the cyanide tailings can remove all or part of the attached water after this process;

[0049] (3) Oxidation roasting: the cyanide tailings after preheating roasting treatment are fed into a reactor for oxidation roasting, which is the most critical step for breaking cyanide, the internal temperature of the reactor is controlled in the range of 530℃, the residence time of the cyanide tailings in the reactor is in the range of 8min, and oxygen needs to be continuously fed during the oxidation roasting process, and the decyanation tailings are obtained after the oxidation roasting treatment;

[0050] (4) Electric furnace smelting: the cooled decyanation tailings are fed into an electric furnace for smelting, the temperature of the electric furnace smelting pool is in the range of 1200℃, the flue gas is taken away along the negative pressure path, and the negative pressure control range is-1.8KPa, which further smelts the decyanation tailings into water slag and pig iron, the water slag treated can reach the national standard of GBN 164-1982 and can be used as building materials and cement, and the pig iron treated can be used for steelmaking and cast iron.

[0051] Example 3

[0052] A resource utilization and harmless treatment method of gold cyanide tailings, as Figure 1 described, the specific operation steps are:

[0053] (1) Raw material treatment: the cyanide tailings after gold extraction by cyanide leaching process in gold smelting enterprises are filtered by a filter press to reduce the attached water to 15%;

[0054] (2) Preheating roasting: the cyanide tailings containing 15% attached water are fed into a suspension furnace for preheating and dehydration, the toxic and harmful substances in the tailings are destroyed by oxidation and pyrolysis at high temperature, the preheating temperature is kept at 1000℃, the flue gas is taken away along the negative pressure path, the system negative pressure control range is-2.3KPa, and the cyanide tailings can remove all or part of the attached water after this process;

[0055] (3) Oxidation roasting: the cyanide tailings after preheating roasting treatment are fed into a reactor for oxidation roasting, which is the most critical step for breaking cyanide, the internal temperature of the reactor is controlled in the range of 550℃, the residence time of the cyanide tailings in the reactor is in the range of 5min, and oxygen needs to be continuously fed during the oxidation roasting process, and the decyanation tailings are obtained after the oxidation roasting treatment;

[0056] (4) Electric furnace smelting: the cooled decyanation tailings enter the electric furnace smelting, the temperature range of the electric furnace smelting pool is 1500 DEG C, the flue gas is extracted along with the negative pressure path, the control range of the negative pressure is -1.5 KPa, this process further smelts the decyanation tailings into water slag and pig iron, the water slag reaches the national standard of GBN 164-1982 after treatment and can be used as building materials and cement, the pig iron can be used for steelmaking and cast iron after treatment.

Claims

1. A method for resource utilization and harmless treatment of gold cyanidation tailings, characterized in that It comprises the following steps: (1) raw material treatment: the cyanide tailings after gold extraction by cyanide leaching process in gold smelting enterprises, after pressure filtration, the attached water in it is reduced to 15% or less; (2) preheating roasting: the cyanide tailings containing 15% or less attached water enters the suspension furnace for preheating and dehydration, the preheating temperature is kept at 800-1000℃, the flue gas is taken away along the negative pressure path, and the system negative pressure control range is-1~-10KPa; (3) oxidation roasting: the cyanide tailings after preheating roasting treatment enters the reactor for oxidation roasting, the reactor internal control temperature range is 500-800℃, the residence time of the cyanide tailings in the reactor is 10min-2h, oxygen needs to be continuously introduced during the oxidation roasting process, and the de-cyanation tailings with total cyanide content below 0.04mg / kg is obtained after oxidation roasting treatment, and the tail gas generated by oxidation roasting is finally converted into CO2; (4) electric furnace smelting: the cooled de-cyanation tailings enters the electric furnace for smelting, the temperature of the electric furnace smelting pool is in the range of 1000-1500℃, the flue gas is taken away along the negative pressure path, and the negative pressure control range is-1~-10KPa, this process further smelts the de-cyanation tailings into water slag and pig iron, the water slag is treated and used as building materials and cement, the blending ratio is 7-8%, and the pig iron treated can be used for steelmaking and cast iron.

2. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (2), the required preheating temperature is 900-950℃.

3. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (2), the required negative pressure range is-1~-5KPa.

4. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (3), the oxidation roasting temperature is 600-650℃.

5. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (3), the oxidation roasting time is 10min-1h.

6. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (4), the electric furnace smelting pool temperature is 1200-1500℃.

7. The method for resource utilization and harmless treatment of gold cyanidation tailings according to claim 1, characterized in that In the step (4), the control negative pressure range is-1~-5KPa.

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