System and method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings

Abstract

The invention introduces a system and method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, and relates to the technical field of mineral waste slag recovery, the system comprises a stock bin, a screw conveyor, a medicament box, a size mixing barrel, a tungsten and molybdenum reselection unit, a thickener unit, a filter press unit, a stirring barrel, a clean water pump pool and a clean water pool. According to the method, tungsten and molybdenum elements are effectively enriched through the reselection technology of the enrichment concentrator and the suspension concentrator, zero emission of water is achieved in the production process, the technology is simple, operability is high, the production cost is low, and production enterprises can obtain considerable economic benefits. Useful metal tungsten and molybdenum are extracted, harmless treatment is carried out on tailings, and resource utilization of phosphorite is carried out. And a process technology for enriching tungsten and molybdenum by adopting a reselection method is environment-friendly, industrial large-scale production is easy to realize, and a win-win situation of environmental protection, social benefits and enterprise economic benefits is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral waste slag recovery, and in particular to a system and method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings. Background Art

[0002] After roasting and defloating low-grade scheelite and high-pressure leaching with soda, high-pressure leaching slag is obtained by filtration. The main component of the high-pressure leaching slag is calcium carbonate, and it contains less than 0.5% tungsten, less than 0.2% molybdenum, and 15-20% phosphorus pentoxide. The leaching toxicity and heavy metals are both lower than the national standards. In the early stage of the plant construction, the high-pressure leaching slag can be used as phosphate rock powder to produce chemical products such as phosphate fertilizer. Later, due to changes in the national environmental protection hazardous waste policy, the alkali boiling slag was uniformly classified as solid hazardous waste and disposed of in accordance with relevant hazardous waste policies.

[0003] Since ammonium paratungstate (APT) slag is highly alkaline, long-term storage not only occupies a large amount of land, but also poses a threat to the environment. my country's new environmental law lists APT slag as a hazardous waste pollutant and will charge an environmental tax of 1,000 yuan per ton. This is both a challenge and an opportunity for companies. The treatment of tungsten smelting slag is imminent. At the same time, new requirements are put forward for the treatment of tungsten smelting slag. It is not only necessary to extract useful metals, but more importantly, it is necessary to carry out resource recovery and reduction treatment to strive to achieve slag-free emissions. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a system and method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, thereby achieving high-quality utilization of tungsten and molybdenum in low-grade complex scheelite and harmless treatment of tailings.

[0005] The technical solution adopted by the present invention is: A system for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, including a silo, a screw conveyor, a reagent box, a slurry mixing barrel, a tungsten and molybdenum gravity separation unit, a thickening unit, a filter press unit, a mixing barrel, a clean water pump pool and a clean water tank; The silo is connected to the feed port of the slurry mixing barrel through a screw conveyor, and the outlet of the medicine box is connected to the medicine adding port of the slurry mixing barrel; The tungsten-molybdenum re-selection unit comprises an enrichment concentrator I, a suspension concentrator and an enrichment concentrator II; the outlet of the slurry mixing barrel is connected to the enrichment concentrator I through a frequency conversion pump; the tungsten-molybdenum coarse concentrate outlet of the enrichment concentrator I is connected to the suspension concentrator, the concentrate outlet of the suspension concentrator is connected to the filter press III, the middling return of the suspension concentrator is connected to the inlet of the suspension concentrator, and the tailings outlet of the suspension concentrator is connected to the enrichment concentrator II; the coarse concentrate outlet of the enrichment concentrator II is connected to the suspension concentrator; The tailings outlet of enrichment and concentrator I and the tailings outlet of enrichment and concentrator II are connected to thickener I, and the underflow outlet of thickener I is connected to filter press I; the overflow water outlet of thickener I is connected to thickener II through a mixing barrel and a slurry pump; the underflow outlet of thickener II is connected to filter press II; the overflow water of thickener II enters the clean water pump pool, and the clean water pump pool outlet is connected to the clean water tank through a clean water pump; the clean water tank outlet is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing tank respectively through a booster pump and a clean water pump.

[0006] Specifically, the tungsten-molybdenum gravity separation unit is also connected to an accident pool, and the outlet of the accident pool is connected to the thickener I through a pump.

[0007] A method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, the specific steps are: S1. Use the loading tool to feed the raw materials into the silo, and then use the screw conveyor to evenly feed the raw materials into the slurry mixing barrel; the raw material APT slag contains 0.4-1.5% tungsten trioxide, 0.15-0.2% molybdenum, 15-20% phosphorus pentoxide by weight, and the fineness reaches -400 mesh, accounting for 90-95%; S2, the raw material APT slag slurry concentration is 18-22% by weight, and then dilute sulfuric acid with a concentration of 15-25% by weight is added to the slurry mixing barrel through the reagent box to adjust the pH value of the slurry to neutral; S3, the neutral slurry of S2 is transported to the tungsten and molybdenum gravity separation unit through a variable frequency pump, and the following gravity separation steps are carried out: a. Primary enrichment: The slurry enters the enrichment concentrator I for the first enrichment to obtain tungsten and molybdenum rough concentrate; b. Secondary enrichment: The primary enriched tungsten-molybdenum coarse concentrate is fed to the suspension concentrator for re-selection to obtain a tungsten-molybdenum mixed concentrate, which is then directly fed to the filter press III for filtration; c. The middlings from the suspension concentrator are returned to the suspension concentrator for processing, and the tailings from the suspension concentrator are sent to the enrichment concentrator II for scavenging to obtain scavenged coarse concentrate; d. The coarse concentrate obtained by the enrichment concentrator II is fed to the suspension concentrator for re-selection; S4, the tailings from the enrichment and concentrator II, the tailings from the enrichment and concentrator I, and the slurry from the accident pool are all sent to the thickener I for dehydration, and then fed to the filter press I through the filter press pump. The overflow water from the thickener I is mixed with flocculants in the mixing barrel, and then sent to the thickener II for dehydration through the slurry pump, and then enters the filter press II through the filter press pump. The tailings from the filter press I and filter press II have been converted into general solid waste, which can be used for extended utilization of phosphate resources. S5. The overflow water of thickener II enters the clean water pump pool, is transported to the clean water tank by the clean water pump, and then is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing barrel respectively through the booster pump and the clean water pump for use. After the secondary thickening, all the return water is recycled and not discharged.

[0008] Specifically, the stirring speed of the slurry preparation in S2 is 80-120 r / min, and the stirring time is 50-70 minutes.

[0009] Specifically, the feed slurry flow rate of the enrichment and concentrator Ⅰ for the primary enrichment in step a of S3 is 5.0-7.0 t / h, the slurry concentration is 15-20% by weight, there are 10 blanket grooves in total, one roughing and nine sweeping, the ore is fed in sequence, and the enriched concentrates of each blanket groove are combined together to obtain a tungsten-molybdenum coarse concentrate containing 1.0-4.0% tungsten trioxide by weight and a recovery rate of 72-90%.

[0010] Specifically, the slurry flow rate of the secondary enrichment suspension concentrator in step b of S3 is 0.5-1.0 t / h, and the slurry concentration is 15-20% by weight, to obtain a tungsten-molybdenum mixed concentrate containing 15-30% tungsten trioxide by weight and a recovery rate of 60-80%.

[0011] Specifically, the feed slurry flow rate of the enrichment concentrator II in step c of S3 is 5.0-7.0 t / h, the slurry concentration is 15-19% by weight, there are 10 blanket grooves in total, one roughing and nine sweeping, the ore is fed in sequence, and the concentrates of each blanket groove are merged together to obtain the scavenged coarse concentrate.

[0012] Specifically, the feed slurry flow rate of the suspended ore concentrator for gravity separation in step d of S3 is 0.5-1.0 t / h, and the slurry concentration is 15-20% by weight.

[0013] Specifically, the flocculant added to the stirring barrel in S4 is one or more of polyacrylamide, polyaluminium chloride and polyferric sulfate.

[0014] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages: Through the gravity separation process of the enrichment concentrator and the suspension concentrator, the tungsten and molybdenum elements are effectively enriched, and the production process achieves "zero discharge" of water. The process is simple, the operability is strong, and the production cost is low, so that the production enterprise can obtain considerable economic benefits. Not only can the useful metals tungsten and molybdenum be extracted, but also the tailings are harmlessly treated and the phosphate ore is utilized as a resource. The process technology of enriching tungsten and molybdenum by gravity separation is environmentally friendly and easy to realize industrial-scale production, achieving a win-win situation for environmental protection, social benefits and corporate economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0016] Figure 2 It is a process flow chart of the tungsten and molybdenum reselection unit of the present invention. DETAILED DESCRIPTION

[0017] The following is combined with Figure 1-2 The present invention is further explained with reference to the embodiments, which cannot limit the protection scope of the present invention. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention.

[0018] A system for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, including a silo, a screw conveyor, a reagent box, a slurry mixing barrel, a tungsten and molybdenum gravity separation unit, a thickening unit, a filter press unit, a mixing barrel, a clean water pump pool and a clean water tank; The silo is connected to the feed port of the slurry mixing barrel through a screw conveyor, and the outlet of the medicine box is connected to the medicine adding port of the slurry mixing barrel; The tungsten-molybdenum re-selection unit comprises an enrichment concentrator I, a suspension concentrator and an enrichment concentrator II; the outlet of the slurry mixing barrel is connected to the enrichment concentrator I through a frequency conversion pump; the tungsten-molybdenum coarse concentrate outlet of the enrichment concentrator I is connected to the suspension concentrator, the concentrate outlet of the suspension concentrator is connected to the filter press III, the middling return of the suspension concentrator is connected to the inlet of the suspension concentrator, and the tailings outlet of the suspension concentrator is connected to the enrichment concentrator II; the coarse concentrate outlet of the enrichment concentrator II is connected to the suspension concentrator; The tailings outlet of enrichment and concentrator I and the tailings outlet of enrichment and concentrator II are connected to thickener I, and the underflow outlet of thickener I is connected to filter press I; the overflow water outlet of thickener I is connected to thickener II through a mixing barrel and a slurry pump; the underflow outlet of thickener II is connected to filter press II; the overflow water of thickener II enters the clean water pump pool, and the clean water pump pool outlet is connected to the clean water tank through a clean water pump; the clean water tank outlet is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing tank respectively through a booster pump and a clean water pump.

[0019] Preferably, the tungsten-molybdenum gravity separation unit is also connected to an accident pool, and the outlet of the accident pool is connected to the thickener I through a pump. Example 1

[0020] A method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, taking the raw material APT slag containing 0.4% tungsten trioxide, 0.15% molybdenum, 15% phosphorus pentoxide by weight, and a fineness of -400 mesh accounting for 90% as an example, the specific steps are: S1. Use the loading tool to feed the raw materials into the silo, and then use the screw conveyor to evenly feed the raw materials into the slurry mixing barrel.

[0021] S2. The raw material APT slag slurry concentration is 18% by weight, and then dilute sulfuric acid with a concentration of 25% by weight is added to the slurry mixing barrel through the reagent box. The stirring speed is 80r / min and the stirring time is 70 minutes to adjust the pH value of the slurry to neutral.

[0022] S3, the neutral slurry of S2 is transported to the tungsten and molybdenum gravity separation unit through a variable frequency pump, and the following gravity separation steps are carried out: a. Primary enrichment: The slurry enters the enrichment concentrator I for the first enrichment, the feed slurry flow rate is 7.0 t / h, the slurry concentration is 15% by weight, one roughing and nine sweeping, a total of 10 blanket trenches, feed ore in sequence, the concentrates of each blanket trench are combined together, and a tungsten-molybdenum rough concentrate containing 1.15% tungsten trioxide by weight and a recovery rate of 74.6% is obtained; b. Secondary enrichment: The primary enriched tungsten-molybdenum coarse concentrate is fed to the suspension concentrator for re-selection, with a feed slurry flow rate of 0.5t / h and a slurry concentration of 15% by weight, to obtain a tungsten-molybdenum mixed concentrate containing 16.6% tungsten trioxide by weight and a recovery rate of 62.3%. The tungsten-molybdenum mixed concentrate is directly fed into the filter press III for filtration; c. The middlings from the suspension concentrator are returned to the suspension concentrator for processing, and the tailings from the suspension concentrator are fed to the enrichment concentrator II for scavenging. The feed slurry flow rate is 7.0 t / h, and the slurry concentration is 15% by weight. There are 10 blanket trenches, one roughing and nine scavenging, which are fed in sequence. The concentrates from each blanket trench are combined to obtain scavenged coarse concentrates; d. The coarse concentrate obtained by the enrichment concentrator II is fed to the suspension concentrator for gravity separation. The feed slurry flow rate of the suspension concentrator for gravity separation is 0.5t / h, and the slurry concentration is 15% by weight.

[0023] S4, the tailings from the enrichment and concentrator II, the tailings from the enrichment and concentrator I, and the slurry from the accident pool all enter the thickener I for dehydration, and then are fed to the filter press I through the filter press pump. The overflow water from the thickener I is added with polyferric sulfate in the mixing barrel for slurry adjustment, and then is transported to the thickener II for dehydration through the slurry pump, and then enters the filter press II through the filter press pump; the tailings from the filter press I and filter press II have been converted into general solid waste, which can be used for extended utilization of phosphate resources.

[0024] S5. The overflow water of thickener II enters the clean water pump pool, is transported to the clean water tank by the clean water pump, and then is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing barrel respectively through the booster pump and the clean water pump for use. After the secondary thickening, all the return water is recycled and not discharged. Example 2

[0025] A method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, taking the raw material APT slag containing 1.5% tungsten trioxide, 0.2% molybdenum, 20% phosphorus pentoxide by weight, and a fineness of -400 mesh accounting for 95% as an example, the specific steps are: S1. Use the loading tool to feed the raw materials into the silo, and then use the screw conveyor to evenly feed the raw materials into the slurry mixing barrel.

[0026] S2. The raw material APT slag slurry concentration is 22% by weight, and then dilute sulfuric acid with a concentration of 15% by weight is added into the slurry mixing barrel through the reagent box. The stirring speed is 120r / min, the stirring time is 50 minutes, and the pH value of the slurry is adjusted to neutral.

[0027] S3, the neutral slurry of S2 is transported to the tungsten and molybdenum gravity separation unit through a variable frequency pump, and the following gravity separation steps are carried out: a. Primary enrichment: The slurry enters the enrichment concentrator I for the first enrichment, the feed slurry flow rate is 5.0 t / h, the slurry concentration is 20% by weight, one roughing and nine sweeping, a total of 10 blanket trenches, feed the ore in sequence, the concentrates of each blanket trench are combined together, and a tungsten-molybdenum rough concentrate containing 3.35% tungsten trioxide by weight and a recovery rate of 85.8% is obtained; b. Secondary enrichment: The primary enriched tungsten-molybdenum coarse concentrate is fed to the suspension concentrator for re-selection, with a feed slurry flow rate of 1.0 t / h and a slurry concentration of 20% by weight, to obtain a tungsten-molybdenum mixed concentrate containing 28.8% tungsten trioxide by weight and a recovery rate of 73.2%. The tungsten-molybdenum mixed concentrate is directly fed into the filter press III for filtration; c. The middlings from the suspension concentrator are returned to the suspension concentrator for processing, and the tailings from the suspension concentrator are fed to the enrichment concentrator II for scavenging. The feed slurry flow rate is 5.0 t / h, and the slurry concentration is 19% by weight. There are 10 blanket trenches, one roughing and nine scavenging, which are fed in sequence. The concentrates from each blanket trench are combined to obtain scavenged coarse concentrates; d. The coarse concentrate obtained by the enrichment concentrator II is fed to the suspension concentrator for gravity separation. The feed slurry flow rate of the suspension concentrator for gravity separation is 1.0 t / h, and the slurry concentration is 20% by weight.

[0028] S4, the tailings from the enrichment and concentrator II, the tailings from the enrichment and concentrator I, and the slurry from the accident pool all enter the thickener I for dehydration, and then are fed to the filter press I through the filter press pump. The overflow water from the thickener I is mixed with polyacrylamide and polyaluminium chloride in a mixing barrel for slurry adjustment, and then is transported to the thickener II for dehydration through a slurry pump, and then enters the filter press II through the filter press pump. The tailings from the filter press I and filter press II have been converted into general solid waste, which can be used for extended utilization of phosphate resources.

[0029] S5. The overflow water of thickener II enters the clean water pump pool, is transported to the clean water tank by the clean water pump, and then is transported to the raw material slurry mixing barrel and tungsten-molybdenum gravity separation unit respectively by the booster pump and the clean water pump for use. After the secondary thickening, all the return water is recycled and not discharged.

[0030] Parts of the present invention not described in detail are prior art.

[0031] The embodiments selected herein for the purpose of disclosing the invention are currently considered to be suitable, but it should be understood that the invention is intended to include all changes and modifications of the embodiments that fall within the scope of the concept and invention.

Claims

1. A system for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, characterized by: It includes silo, screw conveyor, reagent box, slurry mixing barrel, tungsten-molybdenum gravity separation unit, thickener, filter press, mixing barrel, clean water pump pool and clean water tank; The silo is connected to the feed port of the slurry mixing barrel through a screw conveyor, and the outlet of the medicine box is connected to the medicine adding port of the slurry mixing barrel; The tungsten-molybdenum re-selection unit comprises an enrichment concentrator I, a suspension concentrator and an enrichment concentrator II; the outlet of the slurry mixing barrel is connected to the enrichment concentrator I through a frequency conversion pump; the tungsten-molybdenum coarse concentrate outlet of the enrichment concentrator I is connected to the suspension concentrator, the concentrate outlet of the suspension concentrator is connected to the filter press III, the middling ore return of the suspension concentrator is connected to the inlet of the suspension concentrator, and the tailings outlet of the suspension concentrator is connected to the enrichment concentrator II; The coarse concentrate outlet of enrichment and concentrator II is connected to the suspension concentrator; the tailings outlet of enrichment and concentrator I and the tailings outlet of enrichment and concentrator II are connected to thickener I, and the underflow outlet of thickener I is connected to filter press I; the overflow water outlet of thickener I is connected to thickener II through a mixing barrel and a slurry pump; the underflow outlet of thickener II is connected to filter press II; the overflow water of thickener II enters the clean water pump pool, and the outlet of the clean water pump pool is connected to the clean water tank through a clean water pump; the outlet of the clean water tank is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing tank respectively through a booster pump and a clean water pump.

2. The system for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 1 is characterized by: The tungsten-molybdenum reselection unit is also connected to an accident pool, and the outlet of the accident pool is connected to the thickener I through a pump.

3. A method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings, characterized in that: The system for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to any one of claims 1 or 2 is used to recover tungsten and molybdenum and treat tailings, and the specific steps are as follows: S1. Use the loading tool to feed the raw materials into the silo, and then use the screw conveyor to evenly feed the raw materials into the slurry mixing barrel; the raw material APT slag contains 0.4-1.5% tungsten trioxide, 0.15-0.2% molybdenum, 15-20% phosphorus pentoxide by weight, and the fineness reaches -400 mesh, accounting for 90-95%; S2. The concentration of raw material APT slag slurry is 18-22% by weight, and then dilute sulfuric acid with a concentration of 15-25% by weight is added to the slurry mixing barrel through the reagent box to adjust the pH value of the slurry to neutral; S3, the neutral slurry of S2 is transported to the tungsten and molybdenum gravity separation unit through a variable frequency pump, and the following gravity separation steps are carried out: a. Primary enrichment; The slurry enters the enrichment concentrator I for the first enrichment to obtain tungsten and molybdenum rough concentrate; b. Secondary enrichment: The primary enriched tungsten-molybdenum coarse concentrate is fed to the suspension concentrator for re-selection to obtain a tungsten-molybdenum mixed concentrate, which is then directly fed to the filter press III for filtration; c. The middlings from the suspension concentrator are returned to the suspension concentrator for processing, and the tailings from the suspension concentrator are sent to the enrichment concentrator II for scavenging to obtain scavenged coarse concentrate; d. The coarse concentrate obtained by the enrichment concentrator II is fed to the suspension concentrator for re-selection; S4, the tailings from the enrichment and concentrator II, the tailings from the enrichment and concentrator I, and the slurry from the accident pool are all sent to the thickener I for dehydration, and then fed to the filter press I through the filter press pump. The overflow water from the thickener I is mixed with flocculants in the mixing barrel, and then sent to the thickener II for dehydration through the slurry pump, and then enters the filter press II through the filter press pump. The tailings from the filter press I and filter press II have been converted into general solid waste, which can be used for extended utilization of phosphate resources. S5. The overflow water of thickener II enters the clean water pump pool, is transported to the clean water tank by the clean water pump, and then is transported to the tungsten-molybdenum gravity separation unit and the raw material slurry mixing barrel respectively through the booster pump and the clean water pump for use. After the secondary thickening, all the return water is recycled and not discharged.

4. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The stirring speed of the slurry preparation in S2 is 80-120 r / min, and the stirring time is 50-70 minutes.

5. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The feed slurry flow rate of the enrichment and concentrator I for the primary enrichment in step a of S3 is 5.0-7.0 t / h, the slurry concentration is 15-20% by weight, there are 10 blanket grooves in total, one roughing and nine sweeping, the ore is fed in sequence, and the enriched concentrates of each blanket groove are combined together to obtain a tungsten-molybdenum coarse concentrate containing 1.0-4.0% tungsten trioxide by weight and a recovery rate of 72-90%.

6. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The slurry flow rate of the secondary enrichment suspension concentrator in step b of S3 is 0.5-1.0 t / h, and the slurry concentration is 15-20% by weight, to obtain a tungsten-molybdenum mixed concentrate containing 15-30% tungsten trioxide by weight and a recovery rate of 60-80%.

7. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The feed slurry flow rate of the enrichment concentrator II in step c of S3 is 5.0-7.0 t / h, and the slurry concentration is 15-19% by weight. There are 10 blanket grooves, one roughing and nine sweeping, which are fed in sequence. The concentrates of each blanket groove are combined together to obtain the scavenged coarse concentrate.

8. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The feed slurry flow rate of the suspended ore concentrator for gravity separation in step d of S3 is 0.5-1.0 t / h, and the slurry concentration is 15-20% by weight.

9. The method for recovering tungsten and molybdenum from low-grade APT slag and treating tailings according to claim 3, characterized in that: The flocculant added to the stirring barrel in S4 is one or more of polyacrylamide, polyaluminium chloride and polyferric sulfate.

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