CN111560518B - Treatment method of copper-containing molybdenum concentrate - Google Patents

Abstract

The invention relates to a processing method of copper-containing molybdenum concentrate, which is characterized in that the copper-containing molybdenum concentrate is ground to obtain mineral powder; uniformly mixing mineral powder and water according to the mass ratio of 1:3-5, carrying out primary oxygen pressure leaching, and carrying out solid-liquid separation to obtain a first leaching solution and first leaching residues; uniformly mixing the first leaching residue with water according to the mass ratio of 1:6-9, carrying out two-stage oxygen pressure leaching, and then carrying out solid-liquid separation to obtain a second leaching solution and second leaching residue; performing alkaline leaching treatment on the second leaching residue to obtain ore pulp with the pH value of 8-10; mixing the second leaching solution with the ore pulp, and reacting to obtain mixed slurry; and carrying out solid-liquid separation on the mixed slurry to obtain third leaching residue and a third leaching solution rich in molybdenum. The treatment method has high leaching rate and effectively utilizes acid.

Description

Treatment method of copper-containing molybdenum concentrate

Technical Field

The invention relates to a method for treating copper-containing molybdenum concentrate, and belongs to the field of hydrometallurgy.

Background

Molybdenum is widely used as an important rare metal in industrial fields such as steel, catalysts, pigments and the like. The average molybdenum content in the earth's crust is only 1.11g/t, copper-molybdenum ore is one of the main sources of metallic molybdenum, usually present in porphyry-type copper ores and skarn-type copper deposits, and nearly half of the molybdenum yield is derived from the associated recovery of copper-molybdenum ore, so that the molybdenum concentrate usually contains copper. At present, the direct oxidation roasting-ammonia leaching-acid precipitation process is mainly adopted for industrially treating molybdenum concentrate (molybdenite), the principle flow is that the molybdenum concentrate is converted into molybdenum trioxide which is easy to be leached by ammonia water through oxidation roasting, and the leaching solution is purified and subjected to acid precipitation to produce ammonium molybdate. The roasting of the molybdenum concentrate generally adopts a multi-hearth furnace, a fluidized bed roaster, a rotary kiln, a reverberatory furnace and the like. In the direct oxidation roasting process of molybdenite, the roasting product molybdenum trioxide is easy to sublime and lose due to overhigh temperature, and the molybdenum trioxide and associated metal molybdate generate eutectic mixtures to sinter materials to influence the product desulfurization and low SO content₂The concentrated flue gas is difficult to be used for preparing acid, thereby polluting the environment and causing the volatilization loss of the associated rhenium element. Therefore, an environment-friendly, efficient and economical smelting technology is urgently needed to replace the existing smelting technology.

The whole hydrometallurgy can fundamentally avoid harmful gas SO₂The metal recovery rate is greatly improved compared with the traditional method, associated metal rhenium can be comprehensively recovered, low-grade and complex molybdenite can be processed, and continuous production and automation of the leaching process are easy to realize. At present, more molybdenite hydrometallurgical methods are formed, and are generally divided into atmospheric pressure oxidative decomposition and high pressure oxidative decomposition. The atmospheric oxidative decomposition mainly comprises nitric acid or nitrate oxidative decomposition, sodium hypochlorite leaching, electrooxidation leaching, biological oxidation leaching and the like, and the processes have the defects of high oxidant consumption and sewage water consumptionLarge treatment difficulty, chlorine pollution or low leaching efficiency and the like.

The high-pressure oxidation decomposition of the molybdenum concentrate mainly comprises a pressure alkaline leaching method and a pressure oxidation method. The pressure alkaline leaching method adopts Na₂CO₃And alkaline reagents such as NaOH and the like are used for leaching the molybdenum concentrate, the process has the disadvantages of high alkali consumption and high auxiliary production cost. The pressure oxidation method comprises adding a certain amount of water, leaching under oxygen pressure, and adding MoS₂Conversion to MoO₃And then the subsequent alkaline leaching process is carried out. Chinese patent CN101323915B proposes that finely ground molybdenum-nickel ore is subjected to oxygen pressure water leaching to obtain leaching solution containing molybdenum and nickel and leaching residue containing molybdenum oxide, the leaching solution is subjected to extraction separation of molybdenum and nickel to produce nickel salt and ammonium molybdate or molybdenum trioxide, and the molybdenum in the leaching residue is subjected to normal pressure alkaline leaching, purification and acid precipitation to recover ammonium molybdate. Chinese patent CN106477630B is to perform oxygen pressure water leaching on molybdenite, after liquid-solid separation, the leaching solution is sent to an ion exchange method or an extraction process to recover molybdate radical ions, and leaching residues are subjected to ammonia leaching, filtering and crystallization to obtain an ammonium molybdate product. U.S. Pat. No. 4, 8753591, 2 also uses oxygen pressure water leaching, leaching residue normal pressure alkali leaching, mixed acid leaching and molybdenum extraction to treat molybdenite.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for treating copper-molybdenum-containing concentrate, which is used for efficiently leaching copper and molybdenum.

In order to solve the technical problems, the technical scheme of the invention is as follows:

a method for treating copper-containing molybdenum concentrate comprises the following steps:

s1, grinding the copper-molybdenum-containing concentrate to obtain mineral powder;

wherein, in the copper-containing molybdenum concentrate, the content of Mo is 25-35 wt%, further 27-33 wt%, and the content of Cu is 5-9 wt%, further 5.2-8.5 wt%;

s2, uniformly mixing the mineral powder obtained in the step S1 and water according to the mass ratio of 1:3-5 (further 1:3.2-4.8), carrying out primary oxygen pressure leaching, and carrying out solid-liquid separation to obtain a first leaching solution and first leaching residues;

wherein, during the first-stage oxygen pressure leaching, the temperature is controlled to be 110-150 ℃, further 120-140 ℃, the total pressure is 0.6-1.0MPa, further 0.7-0.9MPa, the leaching time is 1-3h, further 1.2-2.8 h; in the first leaching solution, the copper content is 12-30g/L, and the sulfuric acid concentration is less than 25 g/L;

s3, uniformly mixing the first leaching residue obtained in the step S2 and water according to the mass ratio of 1:6-9 (further 1:7-8), carrying out two-stage oxygen pressure leaching, and then carrying out solid-liquid separation to obtain a second leaching solution and a second leaching residue;

wherein, during the two-stage oxygen pressure leaching, the temperature is controlled to be 210-230 ℃, further to be 215-225 ℃, the total pressure is 2.5-3.5MPa, further to be 2.7-3.2MPa, the leaching time is 2-4h, further to be 2.5-3.5 h; in the second leaching solution, the content of molybdenum is 3-20g/L, and the concentration of sulfuric acid is less than 100 g/L;

s4, performing alkaline leaching treatment on the second leaching residue obtained in the step S3 to obtain ore pulp with the pH value of 8-10;

s5, mixing the second leaching solution obtained in the step S3 with the ore pulp obtained in the step S4, reacting, and adjusting acid by using the second leaching solution to obtain mixed slurry;

and S6, carrying out solid-liquid separation on the mixed slurry obtained in the step S5 to obtain third leaching slag and a third leaching solution rich in molybdenum.

Wherein, in the third leaching solution, the content of molybdenum is 20-40g/L, and the concentration of sulfuric acid is less than 40 g/L; further, in S1, the copper-containing molybdenum concentrate was ground to D90<30 μm. The applicant repeatedly researches and discovers that the grinding degree can meet the requirement of high-efficiency leaching without greatly increasing the cost and the grinding time.

Further, in S2, the first leaching solution contains 15-25 g/L of copper and 15-23g/L of sulfuric acid.

Further, after S2, copper in the first leachate is recovered by extraction. Optionally, the concentration of the extracting agent is 15% -30%, and the ratio (O/A) is 0.25/1-2.5/1. Copper electrodeposition waste liquid is used as a stripping agent, and the phase ratio (O/A) is 1: 1-3: 1.

Further, in S3, the content of molybdenum in the second leaching solution is 4-16g/L, and the concentration of sulfuric acid is 80-98 g/L.

Further, in S4, in the alkaline leaching treatment, the leaching temperature is controlled to be 20-80 ℃, further 25-75 ℃, the liquid-solid mass ratio is 1-3:1, further 1.2-2.8:1, and the leaching time is 2-4 hours, further 2.2-3.5 hours. Atmospheric leaching is preferred.

Further, in S4, when the alkaline leaching is performed, the leachate contains one or more of sodium carbonate, sodium hydroxide, and ammonia water.

Further, in S6, the content of molybdenum in the third leaching solution is 25-38g/L, and the concentration of sulfuric acid is 25-35 g/L.

Further, after S6, molybdenum in the third leach solution is recovered by extraction to obtain an aqueous phase and a molybdenum-rich organic phase. Optionally, the organic phase is a conventional process solvent.

Further, the organic phase is back-extracted by ammonia water, and then is subjected to acid precipitation and crystallization to obtain ammonium molybdate.

The process principle of the invention is as follows:

2CuFeS₂+H₂SO₄+8.5O₂＝2CuSO₄+Fe₂(SO₄)₃+H₂O

Cu₂S+2.5O₂+H₂SO₄＝2CuSO₄+H₂O

MoS₂+4.5O₂+2H₂O＝MoO₃+2H₂SO₄

MoS₂+4.5O₂+3H₂O＝H₂MoO₄+2H₂SO₄

MoO₃+Na₂CO₃＝Na₂MoO₄+CO₂

MoO₃+2NaOH＝Na₂MoO₄+H₂O

when the applicant conducts leaching research on the copper-containing molybdenum concentrate (with the Mo content of 25-35 wt% and the Cu content of 5-9 wt%) by using CN101323915B, CN106477630B and US8753591B2, the final leaching rate of molybdenum is not higher than 60%, the expected result of the related technology cannot be obtained, and the conversion rate of molybdenum is sharply reduced along with the increase of the copper content in the raw material. For example, when the copper content is 5.5%, the molybdenum conversion is 54.51%; when the copper grade is 7.1 percent, the conversion rate of molybdenum is 45.81 percent; when the copper grade is 8.5%, the molybdenum conversion is 28.5%. Therefore, the copper in the molybdenum concentrate has obvious inhibition effect on the conversion of the molybdenum sulfide into the molybdenum oxide.

Compared with the prior art, the invention has the following beneficial effects:

(1) because the copper content in the molybdenum concentrate has a great inhibiting effect on the efficiency of converting molybdenum sulfide into molybdenum oxide, the invention adopts a two-stage oxygen pressure leaching process, the first stage leaches out copper under a mild condition, the first stage leaches out copper by extraction, and the copper and the molybdenum in the molybdenum concentrate are separated and recovered by one process. The molybdenum sulfide is converted into molybdenum oxide by the first-stage leaching residue under the strengthened condition, so that the subsequent alkaline leaching under normal pressure is facilitated, and the final molybdenum leaching rate can reach more than 98%.

(2) Because the first stage of oxygen pressure leaching has mild condition, the leachate has low acid content and does not need neutralization, and copper extraction can be directly carried out. The alkaline leaching filtrate is mixed with the second-stage leaching solution with higher acid content, so that the technical effect of reducing acid can be achieved, the efficient extraction of molybdenum is facilitated, and the problem of post-treatment of acid is solved.

(3) The lime can be used for neutralizing the molybdenum raffinate, so that a gypsum product is obtained, and the additional value of the product is increased.

Drawings

Fig. 1 is a process flow diagram of a method of treatment of copper-containing molybdenum concentrate according to the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by those skilled in the art without any creative work based on the embodiments of the present invention belong to the protection scope of the present invention.

Example 1

In this example, the treatment method of the copper-containing molybdenum concentrate is as follows:

(1) 100g of copper-containing molybdenum concentrate (containing 27.5 wt% of Mo, 5.5 wt% of Cu and 24.6 wt% of S) was ground until D90 was <30 μm.

(2) Uniformly mixing the finely ground molybdenum concentrate and water according to a ratio of 1:3.2, adding the mixture into an autoclave to perform primary oxygen pressure leaching under the leaching conditions of 135 ℃ and a total pressure of 0.7Mpa for 1.5 hours. The liquid-solid separation obtains a first stage copper-containing filtrate (copper 16.9g/L, sulfuric acid 18.4g/L) and a first stage leaching residue (copper 0.11 wt%), and the leaching rate of copper is 98.16 wt%.

(3) And (3) extracting copper from the first-stage copper-containing filtrate by adopting 25% of extractant and 75% of kerosene (v/v) in a ratio of (O/A) to (1: 1), performing two-stage extraction, wherein the raffinate contains 0.15g/L of copper, and the copper extraction rate is 99.11 wt%. Copper back extraction adopts copper electrodeposition waste liquid, the ratio (O/A) is 1.5:1, three-stage back extraction is carried out, and back extraction liquid is sent to copper electrodeposition.

(4) And (3) uniformly mixing the first-stage leaching residue obtained in the step (2) with water according to a ratio of 1:8, adding the mixture into an autoclave for second-stage oxygen pressure leaching, wherein the leaching conditions are 220 ℃, the total pressure is 3.0MPa, and the leaching time is 2.5 hours. And (3) carrying out liquid-solid separation to obtain a second-stage leaching solution and second-stage leaching residues, wherein the second-stage leaching solution contains 6.8g/L of molybdenum and 94.2g/L of sulfuric acid. The second-stage leaching residue contains 31.56 wt% of molybdenum, wherein the molybdenum oxide accounts for 99.30 wt% of the total amount of the molybdenum.

(5) Adopting Na as the second-stage leaching residue obtained in the step (4)₂CO₃Leaching for 2.2h at 30 deg.C and liquid-solid ratio of 2:1 under normal pressure. The alkaline leaching solution contains 157.0g/L of molybdenum and has a pH value of 8. The alkaline leaching residue contains 1.03 wt% of molybdenum, and the leaching rate of the molybdenum is 99.50 wt%.

(6) And (5) uniformly stirring the second-stage filtrate obtained in the step (4) and the ore pulp obtained in the step (5), adjusting acid, and performing liquid-solid separation to obtain filtrate and filter residue. The filtrate contains 30.8g/L of molybdenum and 30.2g/L of sulfuric acid. The filter residue contains 0.4 wt% of molybdenum.

(7) And (4) separating molybdenum from the filtrate obtained in the step (6) by adopting a conventional process solvent extraction method, wherein a molybdenum back extraction solution is ammonia water, and then performing acid precipitation and crystallization to prepare an ammonium molybdate product.

Comparative example 1

For the raw material in example 1, the molybdenum concentrate is directly leached by using the process conditions of the second stage leaching in the step (4) in example 1 without a first stage copper leaching process, and the experimental results are shown in table 1.

Table 1 comparative example 1 oxygen pressure leach results

The oxygen pressure leaching residue was subjected to alkaline leaching under atmospheric pressure under the process conditions of step (5) in example 1, and the results are shown in Table 2.

Table 2 comparative example 1 results of alkaline leaching under atmospheric pressure

As can be seen from Table 1, the molybdenum oxide in the leaching residue accounts for a low proportion of the total molybdenum content, mainly because the copper in the concentrate influences the MoS in the oxygen pressure leaching process₂Conversion to MoO₃The conversion of (a). Therefore, the leaching rate of molybdenum resulting in the alkaline leaching under atmospheric pressure in table 2 was low.

Example 2

In this example, the treatment method of the copper-containing molybdenum concentrate is as follows:

(1) 100g of copper-containing molybdenum concentrate (containing 32.2 wt% of Mo, 7.1 wt% of Cu and 25.1 wt% of S25 wt%) was ground until D90 was <30 μm.

(2) Uniformly mixing the finely ground molybdenum concentrate and water according to a ratio of 1:4, adding the mixture into an autoclave to perform primary oxygen pressure leaching under the leaching conditions of 140 ℃ and a total pressure of 0.9Mpa for 2.5 hours. The liquid-solid separation obtains a first stage copper-containing filtrate (copper 17.5g/L, sulfuric acid 21.5g/L) and a first stage leaching residue (copper 0.08 wt%), and the leaching rate of copper is 98.98 wt%.

(3) And extracting copper from the first-stage copper-containing filtrate by adopting 25% of extractant and 75% of kerosene (v/v) in a ratio (O/A) of 1:1, performing two-stage extraction, wherein the copper content of raffinate is 0.12g/L, and the copper extraction rate is 99.32 wt%. Copper back extraction adopts copper electrodeposition waste liquid, the ratio (O/A) is 1.5:1, three-stage back extraction is carried out, and back extraction liquid is sent to copper electrodeposition.

(4) And (3) uniformly mixing the first-stage leaching residue obtained in the step (2) with water according to a ratio of 1:7, adding the mixture into an autoclave for second-stage oxygen pressure leaching, wherein the leaching conditions are 225 ℃, the total pressure is 3.2MPa, and the leaching time is 3.5 hours. And (3) carrying out liquid-solid separation to obtain a second-stage leaching solution and second-stage leaching residues, wherein the second-stage leaching solution contains 7.5g/L of molybdenum and 97.8g/L of sulfuric acid. The second-stage leaching residue contains 38.56 wt% of molybdenum, wherein the molybdenum oxide accounts for 99.50 wt% of the total molybdenum.

(5) And (4) leaching the second-stage leaching residue obtained in the step (4) by using NaOH for 3 hours at the leaching temperature of 75 ℃, the liquid-solid ratio of 2.8:1 and the normal pressure. The alkaline leaching solution contains 128.4g/L of molybdenum and has a pH value of 9.5. The alkaline leaching residue contains 0.33 wt% of molybdenum, and the leaching rate of the molybdenum is 99.90 wt%.

(6) And (5) uniformly stirring the second-stage filtrate obtained in the step (4) and the ore pulp obtained in the step (5), adjusting acid, and performing liquid-solid separation to obtain filtrate and filter residue. The filtrate contained 37.6g/L of molybdenum and 33.8g/L of sulfuric acid. The filter residue contains 0.42 wt% of molybdenum.

(7) And (4) separating molybdenum from the filtrate obtained in the step (6) by adopting a conventional process solvent extraction method, wherein a molybdenum back extraction solution is ammonia water, and then performing acid precipitation and crystallization to prepare an ammonium molybdate product.

Comparative example 2

For the raw material in example 2, the molybdenum concentrate was directly leached by the process conditions of the second stage leaching in step (4) in example 2 without a first stage copper leaching process, and the experimental results are shown in table 3.

Table 3 comparative example 2 oxygen pressure leach results

The oxygen pressure leaching residue was subjected to alkaline leaching under atmospheric pressure under the process conditions of step (5) in example 2, and the results are shown in Table 4.

Table 4 comparative example 2 results of alkaline leaching at atmospheric pressure

Similarly, it can be seen from table 3 that the molybdenum oxide in the leaching residue accounts for a low proportion of the total molybdenum content, mainly because the copper in the concentrate affects MoS in the oxygen pressure leaching process₂Conversion to MoO₃The conversion of (a). Therefore, the leaching rate of molybdenum resulting in the alkaline leaching under atmospheric pressure in Table 4 was low.

The foregoing examples are set forth to illustrate the present invention more clearly and are not to be construed as limiting the scope of the invention, which is defined in the appended claims to which the invention pertains, as modified in all equivalent forms, by those skilled in the art after reading the present invention.

Claims (7)

1. The method for treating the copper-molybdenum-containing concentrate is characterized by comprising the following steps of:

s1, grinding the copper-molybdenum-containing concentrate to obtain mineral powder;

wherein, in the copper-containing molybdenum concentrate, the content of Mo is 25-35 wt%, and the content of Cu is 5-9 wt%; grinding the copper-containing molybdenum concentrate to D90<30 μm;

s2, uniformly mixing the mineral powder obtained in the step S1 and water according to the mass ratio of 1:3-5, carrying out primary oxygen pressure leaching, and carrying out solid-liquid separation to obtain a first leaching solution and first leaching residues;

wherein, when the first-stage oxygen pressure leaching is carried out, the temperature is controlled to be 110-150 ℃, the total pressure is 0.6-1.0Mpa, and the leaching time is 1-3 h; in the first leaching solution, the copper content is 12-30g/L, and the sulfuric acid concentration is less than 25 g/L;

s3, uniformly mixing the first leaching residue obtained in the step S2 and water according to the mass ratio of 1:6-9, carrying out two-stage oxygen pressure leaching, and carrying out solid-liquid separation to obtain a second leaching solution and a second leaching residue;

wherein, during the two-stage oxygen pressure leaching, the temperature is controlled to be 210-230 ℃, the total pressure is 2.5-3.5MPa, and the leaching time is 2-4 h; in the second leaching solution, the content of molybdenum is 3-20g/L, and the concentration of sulfuric acid is less than 100 g/L;

s4, performing alkaline leaching treatment on the second leaching residue obtained in the step S3 to obtain ore pulp with the pH value of 8-10;

wherein, sodium carbonate or sodium hydroxide is adopted for alkaline leaching treatment;

s5, mixing the second leaching solution obtained in the step S3 with the ore pulp obtained in the step S4, reacting, and adjusting acid by using the second leaching solution to obtain mixed slurry;

s6, carrying out solid-liquid separation on the mixed slurry obtained in the step S5 to obtain third leaching slag and a third leaching solution rich in molybdenum;

wherein, in the third leaching solution, the content of molybdenum is 20-40g/L, and the concentration of sulfuric acid is less than 40 g/L;

s7, recovering molybdenum in the third leaching solution through an extraction method to obtain an aqueous phase and an organic phase rich in molybdenum.

2. The treatment method according to claim 1, wherein in S2, the first leaching solution has a copper content of 15-25 g/L and a sulfuric acid concentration of 15-23 g/L.

3. The process of claim 1, wherein after S2, the copper in the first leach solution is recovered by extraction.

4. The treatment method according to claim 1, wherein in S3, the second leachate has a molybdenum content of 4-16g/L and a sulfuric acid concentration of 80-98 g/L.

5. The treatment method according to claim 1, wherein in the step of S4, in the alkaline leaching treatment, the leaching temperature is controlled to be 20-80 ℃, the liquid-solid mass ratio is 1-3:1, and the leaching time is 2-4 h.

6. The treatment method according to claim 1, wherein in S6, the molybdenum content in the third leaching solution is 25-38g/L, and the sulfuric acid concentration is 25-35 g/L.

7. The process according to claim 1, characterized in that the organic phase is stripped with aqueous ammonia, then subjected to acid precipitation and crystallization to obtain ammonium molybdate.

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