A method for recovering sulfur-ignited overfired ore bodies from high-sulfur polymetallic ores

Abstract

This invention discloses a method for recovering spontaneously combusted, overfired ore bodies from high-sulfur polymetallic ores. The method involves spraying a mixture of quicklime and water onto the spontaneously combusted ore pile to extinguish the fire. The polymetallic ore is then filtered, ground, and mixed with sulfuric acid solution. After further grinding, it is mixed with dilute sulfuric acid solution, heated, and stirred for 1-2 hours, followed by filtration to obtain filter residue A and filtrate A. Filtrate A is heated, and calcium carbonate is added to adjust the pH to 4-6. Polyacrylamide is then added, and the mixture is filtered again to obtain filter residue B and filtrate B. Filtrate B is heated, and sodium fluoride, ethylene glycol, and polyacrylamide are added sequentially. After stirring, the mixture is filtered again to obtain filtrate C. Zinc powder is added to filtrate C to displace the zinc, resulting in sponge copper and a solution containing zinc sulfate. Sodium hydroxide solution is added to the zinc sulfate solution to adjust the pH, and the mixture is filtered again to obtain filter residue D. Filter residue D is used for zinc recovery. This invention solves the problems of poor separation efficiency, low metal recovery rate, and high production cost of spontaneously combusted, overfired ore bodies.

Description

Technical Field

[0001] This invention belongs to the field of high-sulfur polymetallic ore mining technology, specifically relating to a method for recovering sulfur-ignited ore bodies in high-sulfur polymetallic ores. Background Technology

[0002] High-sulfur polymetallic ores are primarily sulfide-based minerals, containing metals such as copper, iron, lead, and zinc, as well as valuable elements like sulfur and arsenic. These ores are characterized by dense mineral coexistence, fine grain size, and high separation difficulty. During mining, the ore is often exposed to the open for extended periods, causing oxidation and heat release upon contact with air. If the rate of heat generation exceeds the rate of heat dissipation, the ore accumulates heat and eventually spontaneously combusts. The altered structure and properties of the ore body after spontaneous combustion further complicate separation. Furthermore, the spraying of agents such as lime, calcium-magnesium salt mixtures, alumina, sodium carbonate, water glass, and organic surfactants during fire suppression to inhibit or delay sulfide oxidation leaves residues in the burned ore body. These residues affect the effectiveness of separation reagents, reducing metal recovery rates, and increase the amount of reagents and separation processes required, leading to increased production costs. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention discloses a method for recovering spontaneously combusted ore bodies from high-sulfur polymetallic ores, solving the problems of poor sorting effect, low metal recovery rate, and high production cost of spontaneously combusted ore bodies.

[0004] This invention is achieved using the following technical solution: A method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores includes the following steps: (1) Spray quicklime and water onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, filter the sulfur polymetallic ore and send it to a grinder for grinding to obtain slurry A. The slurry A contains more than 95% particles with a particle size of 80-100 mesh. Then, add sulfuric acid solution with a mass fraction of 80-98% to the slurry A and stir to mix. Then send it to a grinder for grinding to obtain slurry B. The slurry B contains more than 95% particles with a particle size of 200 mesh. (2) The slurry B obtained in step (1) and a sulfuric acid solution with a mass fraction of 20-30% are stirred and mixed in a mass ratio of 1:(0.3-0.4) to obtain slurry C. The slurry C is heated to 60-80℃ and then stirred for 1-2 hours. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and used for lead recovery. (3) Heat the filtrate A obtained in step (2) to 60-80℃ and keep it at a constant temperature. Add calcium carbonate to adjust the pH to 4-6. Then add polyacrylamide and continue stirring for 0.5-1h. Filter to obtain filter residue B and filtrate B. Use the filter residue B for iron recovery. The mass ratio of the polyacrylamide to the volume ratio of the filtrate A is (3-5)g:100L. (4) Heat the filtrate B obtained in step (3) to 30-40°C and keep it at a constant temperature. Add sodium fluoride, ethylene glycol and polyacrylamide in sequence, stir for 0.5-1h and then filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is (10-20) g: (10-20) mL: (30-50) mg: 1L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add sodium hydroxide solution to the solution containing zinc sulfate to adjust the pH to 9-10. Then stir for 1-2 hours and filter to obtain filter residue D. Use filter residue D to recover zinc.

[0005] Furthermore, the stirring speed in step (1) is 400–500 r / min. Controlling a higher stirring speed can promote the mixing of mineral particles with sulfuric acid solution, thereby fully exposing the metal particles in the minerals, which is beneficial for subsequent metal leaching.

[0006] Furthermore, in step (1), the mass ratio of the sulfuric acid solution with a mass fraction of 80-98% to the slurry A is (5-10):100.

[0007] Furthermore, in step (1), a sulfuric acid solution with a mass fraction of 80-98% is added to slurry A and stirred to mix. Then, it is sent to a grinder for grinding for 1-3 hours to obtain slurry B. Controlling the grinding time ensures that the minerals are fully ground, so that the metal particles in the minerals are fully exposed, which is conducive to the leaching of various metals.

[0008] Furthermore, in step (2), the filter residue A is dried and lead is recovered by pyrometallurgical lead smelting.

[0009] Furthermore, the stirring speed in step (3) is 200–300 r / min. Controlling the stirring speed promotes the precipitation and flocculation of metallic iron, thereby improving the separation effect of metallic iron.

[0010] Furthermore, in step (4), the filtrate B obtained in step (3) is heated to 30-40°C and kept at a constant temperature. Sodium fluoride and ethylene glycol are added first and stirred for 20 minutes, and then polyacrylamide is added. Adding sodium fluoride and ethylene glycol first allows sodium fluoride to react with calcium ions to form a precipitate. Adding polyacrylamide then promotes the flocculation of large precipitate particles, thereby improving the separation effect of calcium. It also avoids adding polyacrylamide too early, which would cause unreacted sodium fluoride and other substances to stick together, preventing them from reacting with calcium ions and being removed.

[0011] Furthermore, the mass fraction of the sodium hydroxide solution in step (5) is 20-25%.

[0012] Compared with existing technologies, it has the following advantages: This invention uses quicklime water to extinguish spontaneously combusting high-sulfur polymetallic ore, and then recovers the burned high-sulfur polymetallic ore. Specifically, the ore body is first initially ground, then mixed with a high-concentration sulfuric acid solution and ground further to break down the mineral structure, fully exposing the metal particles in the mineral, which is beneficial for leaching and recovering the metals. Then, sulfuric acid solution is used to leach various metals in the mineral at a certain temperature. At the same time, the lead in the mineral reacts with the sulfuric acid solution to form lead sulfate precipitate, which is collected for lead recovery. Next, the filtrate is heated and calcium carbonate is added to adjust the pH to 4-6 to separate the iron precipitate. Polyacrylamide is added to promote the flocculation of the iron precipitate and improve the separation effect of iron. After the iron is separated and removed, the filtrate is heated and... Sodium fluoride, ethylene glycol, and polyacrylamide are added to remove calcium ions trapped in the filtrate. Sodium fluoride reacts with calcium ions to form calcium fluoride precipitate. A certain amount of ethylene glycol is added simultaneously with sodium fluoride because the reaction of sodium fluoride with calcium ions to form calcium fluoride increases the viscosity of the solution, affecting the dispersion of sodium fluoride and the reaction of calcium ions. Adding ethylene glycol reduces the viscosity of the solution, promotes the dispersion of sodium fluoride, improves the calcium removal effect, and reduces the impact of calcium ions on the subsequent separation and recovery of copper and zinc. Furthermore, the addition of polyacrylamide promotes the flocculation of calcium fluoride precipitate, improving the calcium separation effect. Then, zinc powder is added to replace the calcium fluoride to obtain sponge copper. The pH of the filtrate can be adjusted by adding sodium hydroxide solution to allow for the precipitation and recovery of metallic zinc. Detailed Implementation

[0013] The present invention is further illustrated by the following examples, but these are not intended to limit the invention. Specific experimental conditions and methods not specified in the following examples are generally conventional methods well known to those skilled in the art.

[0014] Example 1: A method for recovering sulfur-ignited overfired ore bodies from high-sulfur polymetallic ores, comprising the following steps: (1) Quicklime and water are mixed and sprayed onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, the sulfur polymetallic ore is filtered and sent to a grinder for grinding to obtain slurry A. The slurry A contains more than 95% particles with a particle size of 85 mesh. Then, an 85% sulfuric acid solution is added to the slurry A and stirred and mixed at a speed of 450 r / min. Then, it is sent to a grinder for grinding for 2 hours to obtain slurry B. The slurry B contains more than 95% particles with a particle size of 200 mesh. The mass ratio of the 85% sulfuric acid solution to slurry A is 6:100. (2) The slurry B obtained in step (1) and the sulfuric acid solution with a mass fraction of 25% are stirred and mixed in a mass ratio of 1:0.32 to obtain slurry C. The slurry C is heated to 65°C and then stirred for 1.5 hours. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and lead is recovered by pyrometallurgical lead smelting. (3) After heating the filtrate A obtained in step (2) to 65°C and keeping it at a constant temperature, calcium carbonate was added to adjust the pH to 4.5. Then polyacrylamide was added and the mixture was stirred at a speed of 250 r / min for 0.8 h. After filtration, filter residue B and filtrate B were obtained. Filter residue B was used for iron recovery. The mass ratio of polyacrylamide to the volume ratio of filtrate A was 3.5 g: 100 L. (4) Heat the filtrate B obtained in step (3) to 32°C and keep it at a constant temperature. First, add sodium fluoride and ethylene glycol and stir for 20 min. Then add polyacrylamide and stir for 0.8 h. Filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is 12 g: 15 mL: 40 mg: 1 L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add sodium hydroxide solution with a mass fraction of 22% to the solution containing zinc sulfate to adjust the pH to 9.5. Then stir and treat for 1.5h and filter to obtain filter residue D. Use filter residue D to recover zinc.

[0015] Example 2: A method for recovering sulfur-ignited overfired ore bodies from high-sulfur polymetallic ores, comprising the following steps: (1) Spray quicklime and water onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, filter the sulfur polymetallic ore and send it to a grinder for grinding to obtain slurry A. More than 95% of the particles in slurry A are 80 mesh. Then, add 80% sulfuric acid solution to slurry A and stir and mix at a speed of 400 r / min. Then send it to a grinder for grinding for 1 hour to obtain slurry B. More than 95% of the particles in slurry B are 200 mesh. The mass ratio of 80% sulfuric acid solution to slurry A is 5:100. (2) The slurry B obtained in step (1) and the sulfuric acid solution with a mass fraction of 20% are stirred and mixed in a mass ratio of 1:0.3 to obtain slurry C. The slurry C is heated to 60°C and then stirred for 1 hour at a constant temperature. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and lead is recovered by pyrometallurgical lead smelting. (3) Heat the filtrate A obtained in step (2) to 60°C and keep it at a constant temperature. Add calcium carbonate to adjust the pH to 4. Then add polyacrylamide and continue to stir for 0.5 h at a speed of 200 r / min. Filter to obtain filter residue B and filtrate B. Use the filter residue B for iron recovery. The mass ratio of the polyacrylamide to the volume ratio of the filtrate A is 3 g: 100 L. (4) Heat the filtrate B obtained in step (3) to 30°C and keep it at a constant temperature. First, add sodium fluoride and ethylene glycol and stir for 20 min. Then add polyacrylamide and stir for 0.5 h. Filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is 10 g: 10 mL: 30 mg: 1 L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add 20% sodium hydroxide solution to the solution containing zinc sulfate to adjust the pH to 9. Then stir and treat for 1 hour and filter to obtain filter residue D. Use filter residue D to recover zinc.

[0016] Example 3: A method for recovering sulfur-ignited overfired ore bodies from high-sulfur polymetallic ores, comprising the following steps: (1) Quicklime and water are mixed and sprayed onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, the sulfur polymetallic ore is filtered and sent to a grinder for grinding to obtain slurry A. The slurry A contains more than 95% particles with a particle size of 95 mesh. Then, a sulfuric acid solution with a mass fraction of 95% is added to the slurry A and stirred and mixed at a speed of 450 r / min. Then, it is sent to a grinder for grinding for 2 hours to obtain slurry B. The slurry B contains more than 95% particles with a particle size of 200 mesh. The mass ratio of the sulfuric acid solution with a mass fraction of 95% to the slurry A is 8:100. (2) The slurry B obtained in step (1) and the sulfuric acid solution with a mass fraction of 28% are stirred and mixed in a mass ratio of 1:0.36 to obtain slurry C. The slurry C is heated to 75°C and then stirred for 1.5 hours. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and lead is recovered by pyrometallurgical lead smelting. (3) After heating the filtrate A obtained in step (2) to 75°C and keeping it at a constant temperature, calcium carbonate was added to adjust the pH to 5.5. Then polyacrylamide was added and stirred for 0.8 hours at a speed of 250 r / min. After filtration, filter residue B and filtrate B were obtained. The filter residue B was used for iron recovery. The mass ratio of the polyacrylamide to the volume ratio of the filtrate A was 4 g: 100 L. (4) Heat the filtrate B obtained in step (3) to 36°C and keep it at a constant temperature. First, add sodium fluoride and ethylene glycol and stir for 20 min. Then add polyacrylamide and stir for 0.8 h. Filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is 18 g: 15 mL: 45 mg: 1 L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add sodium hydroxide solution with a mass fraction of 23% to the solution containing zinc sulfate to adjust the pH to 9.5. Then stir and treat for 1.5h and filter to obtain filter residue D. Use filter residue D to recover zinc.

[0017] Example 4: A method for recovering sulfur-ignited overfired ore bodies from high-sulfur polymetallic ores, comprising the following steps: (1) Spray quicklime and water onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, filter the sulfur polymetallic ore and send it to a grinder for grinding to obtain slurry A. The slurry A contains more than 95% particles with a particle size of 100 mesh. Then, add a 98% sulfuric acid solution to the slurry A and stir and mix it at a speed of 500 r / min. Then send it to a grinder for grinding for 3 hours to obtain slurry B. The slurry B contains more than 95% particles with a particle size of 200 mesh. The mass ratio of the 98% sulfuric acid solution to slurry A is 10:100. (2) The slurry B obtained in step (1) and the sulfuric acid solution with a mass fraction of 30% are stirred and mixed in a mass ratio of 1:0.4 to obtain slurry C. The slurry C is heated to 80°C and then stirred for 2 hours. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and lead is recovered by pyrometallurgical lead smelting. (3) Heat the filtrate A obtained in step (2) to 80°C and keep it at a constant temperature. Add calcium carbonate to adjust the pH to 6. Then add polyacrylamide and continue to stir for 1 hour at a speed of 300 r / min. Filter to obtain filter residue B and filtrate B. Use the filter residue B for iron recovery. The mass ratio of the polyacrylamide to the volume ratio of the filtrate A is 5 g: 100 L. (4) Heat the filtrate B obtained in step (3) to 40°C and keep it at a constant temperature. First, add sodium fluoride and ethylene glycol and stir for 20 min. Then add polyacrylamide and stir for 1 h. Filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is 20 g: 20 mL: 50 mg: 1 L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add sodium hydroxide solution with a mass fraction of 25% to the solution containing zinc sulfate to adjust the pH to 10. Then stir and treat for 2 hours and filter to obtain filter residue D. Use filter residue D to recover zinc.

[0018] Comparative Example 1: The method for recovering spontaneously combusted sulfur-containing polymetallic ore bodies described in this comparative example differs from the method described in Example 1 only in that, in step (1), quicklime and water are mixed and sprayed onto the spontaneously combusting sulfur-containing polymetallic ore pile to extinguish the fire. Then, the sulfur-containing polymetallic ore is filtered and sent to a grinding mill for grinding to obtain slurry A. In slurry A, particles with a particle size of 200 mesh account for more than 95%. Then, in step (2), slurry A obtained in step (1) and sulfuric acid solution with a mass fraction of 25% are stirred and mixed at a mass ratio of 1:0.32 to obtain slurry C.

[0019] Comparative Example 2: The method for recovering the sulfur-ignited and overburned ore body of high-sulfur polymetallic ore described in this comparative example differs from the method described in Example 1 only in that polyacrylamide is not added in step (3).

[0020] Comparative Example 3: The method for recovering the sulfur-ignited and overburned ore body of high-sulfur polymetallic ore described in this comparative example differs from the method described in Example 1 only in that ethylene glycol is not added in step (4).

[0021] Experimental example: High-sulfur polymetallic ores (with sulfur content higher than 25% in the original ore) that have spontaneously combusted and overheated were divided into several batches and recycled according to the methods described in Examples 1-4 and Comparative Examples 1-3. The recovery rates of metals such as copper, zinc, iron and lead were statistically analyzed, and the specific results are shown in Table 1.

[0022] Table 1. Recovery rates of metals such as copper, zinc, iron, and lead obtained after different treatment methods.

[0023] As shown in Table 1, the method of this invention can effectively recover copper, zinc, lead, and iron from high-sulfur polymetallic ores obtained after spontaneous combustion. In contrast, the method of Comparative Example 1 did not add high-concentration sulfuric acid during the grinding of the minerals, which makes it difficult to effectively expose the metal mineral particles and hinders leaching recovery. At the same time, it can convert the ferrous iron in the minerals after combustion into ferric iron, which is beneficial for subsequent separation of metallic iron. The method of Comparative Example 2 did not add polyacrylamide during the precipitation process to remove iron, which is not conducive to the precipitation process and affects the iron recovery rate. The method of Comparative Example 3 did not add ethylene glycol during the removal of calcium and magnesium, which is not conducive to the contact reaction between sodium fluoride and calcium ions in the slurry and reduces the removal efficiency of calcium and magnesium ions.

[0024] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for recovering sulfur-ignited, overfired ore bodies from high-sulfur polymetallic ores, characterized in that: Includes the following steps: (1) Spray quicklime and water onto the spontaneously combusting sulfur polymetallic ore pile to extinguish the fire. Then, filter the sulfur polymetallic ore and send it to a grinder for grinding to obtain slurry A. The slurry A contains more than 95% particles with a particle size of 80-100 mesh. Then, add sulfuric acid solution with a mass fraction of 80-98% to the slurry A and stir to mix. Then send it to a grinder for grinding to obtain slurry B. The slurry B contains more than 95% particles with a particle size of 200 mesh. (2) The slurry B obtained in step (1) and a sulfuric acid solution with a mass fraction of 20-30% are stirred and mixed in a mass ratio of 1:(0.3-0.4) to obtain slurry C. The slurry C is heated to 60-80℃ and then stirred for 1-2 hours. The slurry C is then directly filtered to obtain filter residue A and filtrate A. The filter residue A is dried and used for lead recovery. (3) Heat the filtrate A obtained in step (2) to 60-80℃ and keep it at a constant temperature. Add calcium carbonate to adjust the pH to 4-6. Then add polyacrylamide and continue stirring for 0.5-1h. Filter to obtain filter residue B and filtrate B. Use the filter residue B for iron recovery. The mass ratio of the polyacrylamide to the volume ratio of the filtrate A is (3-5)g:100L. (4) Heat the filtrate B obtained in step (3) to 30-40°C and keep it at a constant temperature. Add sodium fluoride, ethylene glycol and polyacrylamide in sequence, stir for 0.5-1h and then filter to obtain filtrate C. The ratio of sodium fluoride, ethylene glycol and polyacrylamide to filtrate B is (10-20) g: (10-20) mL: (30-50) mg: 1L. (5) Add zinc powder to the filtrate C obtained in step (4) to replace the sponge copper and the solution containing zinc sulfate. Add sodium hydroxide solution to the solution containing zinc sulfate to adjust the pH to 9-10. Then stir for 1-2 hours and filter to obtain filter residue D. Use filter residue D to recover zinc.

2. The method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores according to claim 1, characterized in that: The stirring speed in step (1) is 400-500 r / min.

3. The method for recovering spontaneously combusted sulfur-fired ore bodies in high-sulfur polymetallic ores according to claim 1, characterized in that: In step (1), the mass ratio of sulfuric acid solution with a mass fraction of 80-98% to slurry A is (5-10):

100.

4. The method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores according to claim 1, characterized in that: In step (1), a sulfuric acid solution with a mass fraction of 80-98% is added to slurry A and stirred and mixed. Then, it is sent to a grinder for grinding for 1-3 hours to obtain slurry B.

5. The method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores according to claim 1, characterized in that: In step (2), the filter residue A is dried and lead is recovered by pyrometallurgical lead smelting.

6. The method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores according to claim 1, characterized in that: The stirring speed in step (3) is 200-300 r / min.

7. The method for recovering sulfur-ignited, overburned ore bodies from high-sulfur polymetallic ores according to claim 1, characterized in that: In step (4), the filtrate B obtained in step (3) is heated to 30-40°C and kept at a constant temperature. Sodium fluoride and ethylene glycol are added and stirred for 20 minutes before polyacrylamide is added.

8. The method for recovering spontaneously combusted sulfur-fired ore bodies in high-sulfur polymetallic ores according to claim 1, characterized in that: The sodium hydroxide solution in step (5) has a mass fraction of 20-25%.

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