Molybdenum disulfide acid leaching purification process

Abstract

The invention discloses a molybdenum disulfide acid leaching purification process, relates to the technical field of molybdenum disulfide purification, and aims to solve the problems of waste acid recycling, wastewater treatment and equipment corrosion in the molybdenum disulfide purification process. The molybdenum disulfide acid leaching purification process comprises the following steps: S1, acid purification: adding a molybdenum concentrate raw material into a reaction kettle; adding reaction acid into the reaction kettle according to a certain solid-to-liquid ratio, heating the reaction kettle to react for a period of time, and cooling to dissolve impurities in the molybdenum concentrate; s2, filter pressing and cleaning: conveying the acid-washed material to a plate frame for filter pressing to form a filter cake, cleaning the filter cake with clear water for 2-4 times until the wastewater is neutral, and conveying the filter cake to the plate frame for filter pressing again; s3, repeating acid purification and filter-pressing cleaning for several times until various acids are used up in the process; and S4, drying: putting the cleaned filter cake into a drying system for drying to obtain the high-purity molybdenum disulfide with the purity of more than or equal to 99%. According to the acid leaching purification process, impurities in molybdenum disulfide are selectively dissolved, the purity of molybdenum disulfide is remarkably improved, and the industrial application requirement is met.

Description

Technical Field

[0001] The invention relates to the technical field of molybdenum disulfide purification, in particular to a molybdenum disulfide acid leaching purification process. Background Art

[0002] Molybdenum disulfide (MoS2) is the main component of molybdenite. It is a lead gray to black solid powder with a greasy feel and no odor. It belongs to the hexagonal or orthorhombic system, has a standard hexagonal layered structure, is similar to graphite, and has a metallic luster. As an important solid lubricant, molybdenum disulfide performs well in high temperature, high pressure, low temperature and high vacuum environments, and is known as the "king of advanced solid lubricants." In addition, it also has antimagnetism, can be used as a linear photoconductor and a semiconductor showing P-type or N-type conductivity, has the functions of rectification and energy conversion, and can be used as a catalyst for the dehydrogenation of complex hydrocarbons.

[0003] With the deepening of research, the application requirements of molybdenum disulfide are constantly increasing. High-purity molybdenum disulfide has significantly improved catalytic, mechanical, optical and electrical properties compared with ordinary molybdenum disulfide. Its preparation methods and processes have also gradually developed on a large scale, becoming a research hotspot in the field of materials science. However, traditional purification processes can no longer meet the needs of high-tech industries for the output and properties of molybdenum disulfide. The current production process is "slurrying → flotation heating (adding acidic solutions such as hydrochloric acid and hydrofluoric acid) → hot water washing → drying". Molybdenite is treated with mixed acid heating to remove impurities such as silicon and iron, thereby improving the purity of molybdenum disulfide.

[0004] However, this process has the following defects: First, a variety of acidic solutions such as hydrochloric acid and hydrofluoric acid are required in the purification process, but the waste acid after use is often not effectively recycled, and is usually only discharged after alkali neutralization, resulting in environmental pollution and waste of resources. Secondly, the waste acid has not been effectively recycled and reused, which increases the acid consumption and production costs. In addition, highly corrosive materials will corrode equipment during the purification process, increase the risk of leakage, and thus increase safety hazards and production costs. Furthermore, the waste acid treatment of mixed acids is complicated, which brings difficulties to the subsequent recovery of waste acids. Finally, if the large amount of wastewater generated after purification and separation is not handled properly, it will cause environmental pollution, making it difficult to balance the relationship between "high-quality development and high-level protection."

[0005] Therefore, it is urgent to develop new purification processes to solve the above problems and meet the application needs of high-purity molybdenum disulfide in various fields. Summary of the invention

[0006] In order to solve the above problems, that is, to solve the problems raised by the above background technology, the present invention proposes a molybdenum disulfide acid leaching purification process, which comprises the following steps: S1, acid purification: adding the molybdenum concentrate raw material into a reactor, adding reaction acid into the reactor according to a certain amount of solid-liquid ratio, heating the reactor for reaction for a period of time and then cooling it down to dissolve the impurities in the molybdenum concentrate; S2, filter press cleaning: sending the acid-washed material to a plate-frame filter press to form a filter cake, washing the filter cake with clean water 2 to 4 times until the waste water is neutral, and sending the filter cake to the plate-frame filter press again; S3, repeating acid purification and filter press cleaning several times until all acids in the process are used up; S4, drying: putting the washed filter cake into a drying system for drying to obtain high-purity molybdenum disulfide with a purity of ≥99%; S5, waste acid purification: the generated waste acid is collected separately, and each waste acid is purified and set aside by evaporation and condensation; S6, wastewater purification: the generated waste water is recovered to a wastewater pool, and the waste water is purified and set aside in the manner of industrial wastewater treatment.

[0007] The present invention is further configured as follows: in S1, the reaction acids are hydrochloric acid, hydrofluoric acid, hydrochloric acid, and hydrofluoric acid, and only one is used at a time for acid purification.

[0008] The present invention is further configured as follows: the hydrochloric acid concentration range is 3-6 mol / L, and the reaction time range is 30-80 min.

[0009] The present invention is further configured as follows: the hydrofluoric acid concentration ranges from 2 to 4 mol / L, and the reaction time ranges from 25 to 60 min.

[0010] The present invention is further configured as follows: in S1, the solid-to-liquid ratio of the first acid purification and acid addition is in the range of 1:9-12, and the reaction temperature in the reactor is in the range of 70-100°C.

[0011] The present invention is further configured as follows: in S2, the amount of clean water used for each cleaning is the same as the amount of the corresponding reaction acid used.

[0012] The present invention is further configured as follows: in S3, the solid-to-liquid ratio of repeated acid purification and acid addition is in the range of 1:10-12, and the reaction temperature in the reactor is in the range of 80-110°C.

[0013] The present invention is further configured as follows: in S4, the drying temperature range in the drying system is 150-200°C.

[0014] The present invention is further configured as follows: in said S5, the waste acid purification comprises the following steps: S501, purifying different types of previous waste acids separately, adding sulfuric acid in a concentration range of 20-80% to the evaporator; S502, adding the waste acid to the evaporator, evaporating the mixed acid of sulfuric acid and waste acid, controlling the vacuum degree and temperature of the evaporator, the vacuum degree range is -760mm~-680mm mercury column, the temperature range is 70~100°C, and the evaporated gas is recovered by condensation to obtain recovered acid; S503, after testing the recovered acid, preparing it according to the concentration required for acid purification as the corresponding type of reaction acid.

[0015] The present invention is further configured as follows: in said S6, the wastewater purification comprises the following steps: S601, adjusting the pH value: adding one or more of calcium hydroxide, sodium hydroxide or sodium carbonate in a concentration range of 2-4%, 3-5% or 3-5% to the wastewater, neutralizing the acid in the wastewater, and adjusting the pH value to 9-11; S602, flocculation precipitation: adding a certain amount of one or more of flocculants PAC or PAM to the neutralized wastewater, the amount of PAC added is in the range of 2-5 mg / L, and the amount of PAM added is in the range of 0.1-0.5 mg / L, and after precipitation in a sedimentation tank, removing part of the precipitate and suspended matter; S603, multi-stage filtration and impurity removal: filtering the precipitated wastewater through quartz sand and ultrafiltration in turn, removing calcium ions, fluoride ions and heavy metals through ion exchange resin, and then undergoing two-stage reverse osmosis, and finally EDI purification and desalination, so that the wastewater reaches the ultrapure water standard.

[0016] The beneficial technical effects of the present invention are as follows: the acid leaching purification process of the present invention significantly improves the purity of molybdenum disulfide by selectively dissolving impurities in the molybdenum disulfide, thereby meeting the requirements of industrial applications. At the same time, the process realizes the full recovery and reuse of waste acid, solves the problem of waste acid pollution, reduces the amount of new acid used, and thus reduces production costs and acid pollution risks. In addition, waste water can be recycled after treatment, reducing water resource consumption and improving resource utilization efficiency. The materials used in the equipment in the process effectively resist acid corrosion, extend the service life of the equipment, and ensure the safety of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The process flow chart of the present invention is shown.

[0018] Figure 2 A first test report schematic diagram is shown.

[0019] Figure 3 A second test report schematic diagram is shown. DETAILED DESCRIPTION

[0020] Please refer to the attached Figures 1 to 3Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention. Example

[0021] S1. Acid purification: 500g of -300 mesh molybdenum concentrate raw material is added into a reactor, which is made of steel-lined PTFE material. Then 4000ml of hydrochloric acid is added into the reactor, and the concentration of hydrochloric acid is 4.87mol / l. The temperature in the reactor is controlled at 90°C, and the reaction time is 40min before cooling to 30°C.

[0022] S2. Filter pressing and cleaning: the acid-washed material is sent to the plate and frame filter pressing to form a filter cake, and the waste acid is collected separately; the filter cake is washed with clean water for 3 times, and the amount of clean water added each time is 4000ml, and the waste water is collected; then the filter cake is sent to the plate and frame filter pressing again, and the waste water is collected.

[0023] S3, repeat the acid purification and filter press cleaning 3 times until all acids in the process are used up; The filter cake enters the reactor for the second time, and 4500ml of hydrofluoric acid is added, the concentration of hydrofluoric acid is 3.12mol / l, the temperature in the reactor is controlled at 90℃, and the temperature is lowered to 30℃ after 40min of reaction time, and then enters the plate and frame filter press, and the waste acid is collected separately; the filter cake is washed with clean water 3 times, and the amount of clean water added each time is 4500ml, and the waste water is collected; then the filter cake is sent to the plate and frame filter press again, and the waste water is collected.

[0024] The filter cake enters the reactor for the third time, and 4400ml of hydrochloric acid is added. The concentration of hydrochloric acid is 4.87mol / l. The temperature in the reactor is controlled at 90℃. After 40min of reaction time, the temperature is lowered to 30℃, and then it enters the plate and frame filter press, and the waste acid is collected separately; the filter cake is washed with clean water 3 times, and the amount of clean water added each time is 4400ml, and the waste water is collected; then the filter cake is sent to the plate and frame filter press again, and the waste water is collected.

[0025] The filter cake enters the reactor for the fourth time, and 4500ml of reactive hydrofluoric acid is added, the concentration of hydrofluoric acid is 3.12mol / l, the temperature in the reactor is controlled at 90℃, and the temperature is lowered to 30℃ after 40min of reaction time, and then enters the plate and frame filter press, and the waste acid is collected separately; the filter cake is washed with clean water 3 times, and the amount of clean water added each time is 4500ml, and the waste water is collected; then the filter cake is sent to the plate and frame filter press again, the waste water is collected, and the filter cake enters the next process.

[0026] S4, drying: the filter cake is introduced into a drying system for drying at a temperature of 150°C for 3 hours. The purity of the obtained molybdenum disulfide is 99.12% after testing.

[0027] S5. Waste acid purification: The generated waste acid is collected separately, and each waste acid is purified by evaporation and condensation for later use, including the following steps: S501, purify different types of previous waste acid separately, add sulfuric acid with a concentration range of 50% into the evaporator, the evaporator is made of steel lined with PTFE; S502, adding the waste acid into an evaporator to evaporate the mixed acid of sulfuric acid and the waste acid, controlling the vacuum degree of the evaporator to -730 mm Hg and the temperature to 80° C., recovering the evaporated gas by condensation to obtain recovered acid; S503. After testing the recovered acid, it is prepared according to the concentration required for acid purification and used as the corresponding type of reaction acid. The pipes and valves in the system that come into contact with sulfuric acid, waste acid and recovered acid are all made of PVDF.

[0028] S6. Wastewater purification: The generated wastewater is recycled to the wastewater pool, and the wastewater is purified and used in accordance with the industrial wastewater treatment method, including the following steps: S601, adjust the pH value: add 2.5% calcium hydroxide, 3% sodium hydroxide and 3% sodium carbonate to the wastewater to neutralize the acid in the wastewater and adjust the pH value to 10; S602, flocculation sedimentation: add 3 mg / L PAC and 0.2 mg / L PAM to the neutralized wastewater to accelerate the aggregation of colloidal particles in the water, and remove part of the sediment and suspended matter after sedimentation in the sedimentation tank; S603, multi-stage filtration and impurity removal: the precipitated wastewater is filtered through quartz sand and ultrafiltration in turn to remove part of the precipitate and suspended matter; calcium ions, fluoride ions and heavy metals are removed through ion exchange resin; ions and impurities in the water are removed through two-stage reverse osmosis; finally, EDI purification and desalination are carried out to make the wastewater reach the ultrapure water standard and meet the conditions required for the previous acid purification reaction. After passing the test, it is directly used as water for the previous step. Example

[0029] The difference from the first embodiment is that: S1. Add 4500 ml of hydrochloric acid, the concentration of which is 4.51 mol / L.

[0030] S2. The amount of clean water added each time is 4500ml.

[0031] S3, add 5000ml of hydrofluoric acid, the concentration of hydrofluoric acid is 3.59mol / L, and the amount of clean water added each time is 5000ml; Add 4500ml of hydrochloric acid, the concentration of hydrochloric acid is 4.51mol / l, and the amount of clean water added each time is 4500ml; Add 5000 ml of hydrofluoric acid, the concentration of hydrofluoric acid is 3.59 mol / L, and the amount of clean water added each time is 5000 ml.

[0032] S4. The purity of the obtained molybdenum disulfide was 99.43% after testing.

[0033] S502, control the vacuum degree of the evaporator to -730 mm Hg and the temperature to 85°C.

[0034] S601. Adjust the pH value: Add 3% calcium hydroxide, 3.5% sodium hydroxide and 4% sodium carbonate to the wastewater to neutralize the acid in the wastewater and adjust the pH value to 10.

[0035] S602, flocculation sedimentation: add 3.5 mg / L PAC and 0.3 mg / L PAM to the neutralized wastewater. Example

[0036] The difference from the first embodiment is that: S1. Add 5000 ml of hydrochloric acid, the concentration of which is 3.77 mol / L.

[0037] S2. The amount of clean water added each time is 5000ml.

[0038] S3, add 4400ml of hydrofluoric acid, the concentration of hydrofluoric acid is 3.81mol / L, and the amount of clean water added each time is 4400ml; Add 5000ml of hydrochloric acid, the concentration of hydrochloric acid is 3.77mol / l, and the amount of clean water added each time is 5000ml; Add 4400 ml of hydrofluoric acid, the concentration of which is 3.81 mol / l, and add 4400 ml of clean water each time.

[0039] S4. The purity of the obtained molybdenum disulfide was 99.52% after testing.

[0040] S502, control the vacuum degree of the evaporator to -730 mm Hg and the temperature to 85°C.

[0041] S601. Adjust the pH value: Add 3% calcium hydroxide, 3.5% sodium hydroxide and 3.5% sodium carbonate to the wastewater to neutralize the acid in the wastewater and adjust the pH value to 10.

[0042] S602, flocculation sedimentation: add 3 mg / L PAC and 0.25 mg / L PAM to the neutralized wastewater.

[0043] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0044] In the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The term "comprise" or any other similar term is intended to cover a non-exclusive inclusion, such that a process, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article, or apparatus / device.

[0047] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A molybdenum disulfide acid leaching purification process, characterized in that: The following steps are involved: S1, acid purification: add the molybdenum concentrate raw material into the reactor, add the reaction acid into the reactor according to a certain solid-liquid ratio, heat the reactor for a period of time and then cool it down to dissolve the impurities in the molybdenum concentrate; S2, filter press cleaning: the acid-washed material is sent to the plate and frame filter press to form a filter cake, the filter cake is washed with clean water 2 to 4 times until the wastewater is neutral, and the filter cake is sent to the plate and frame filter press again; S3, repeat the acid purification and filter pressing cleaning several times until all acids in the process are used up; S4, drying: the cleaned filter cake is put into a drying system for drying to obtain high-purity molybdenum disulfide with a purity of ≥99%; S5. Waste acid purification: the generated waste acid is collected separately, and each waste acid is purified by evaporation and condensation for later use; S6. Wastewater purification: The generated wastewater is recycled into the wastewater pool, and the wastewater is purified and set aside in the same way as industrial wastewater treatment.

2. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S1, the reaction acids are hydrochloric acid, hydrofluoric acid, hydrochloric acid, and hydrofluoric acid in the order of only one each time for acid purification.

3. A molybdenum disulfide acid leaching purification process according to claim 2, characterized in that: The hydrochloric acid concentration ranges from 3 to 6 mol / L, and the reaction time ranges from 30 to 80 min.

4. A molybdenum disulfide acid leaching purification process according to claim 2, characterized in that: The hydrofluoric acid concentration ranges from 2 to 4 mol / L, and the reaction time ranges from 25 to 60 min.

5. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S1, the solid-to-liquid ratio of the first acid purification and acid addition is in the range of 1:9-12, and the reaction temperature in the reactor is in the range of 70-100°C.

6. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S2, the amount of clean water used for each cleaning is the same as the amount of the corresponding reaction acid.

7. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S3, the solid-to-liquid ratio of repeated acid purification and acid addition is in the range of 1:10-12, and the reaction temperature in the reactor is in the range of 80-110°C.

8. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S4, the drying temperature in the drying system ranges from 150 to 200°C.

9. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S5, the waste acid purification comprises the following steps: S501, purifying different types of previous waste acids respectively, and adding sulfuric acid with a concentration range of 20-80% into the evaporator; S502, adding waste acid to an evaporator to evaporate a mixed acid of sulfuric acid and waste acid, controlling the vacuum degree and temperature of the evaporator, wherein the vacuum degree ranges from -760 mm to -680 mm of mercury, and the temperature ranges from 70 to 100° C., and recovering the evaporated gas by condensation to obtain recovered acid; S503. After testing the recovered acid, it is prepared according to the concentration required for acid purification and used as the corresponding type of reaction acid.

10. A molybdenum disulfide acid leaching purification process according to claim 1, characterized in that: In S6, wastewater purification comprises the following steps: S601, adjusting pH value: adding one or more of calcium hydroxide, sodium hydroxide or sodium carbonate in a concentration range of 2-4% to 3-5% to the wastewater to neutralize the acid in the wastewater and adjust the pH value to 9-11; S602, flocculation sedimentation: adding a certain amount of one or more flocculants PAC or PAM to the neutralized wastewater, the amount of PAC added is in the range of 2~5mg / L, and the amount of PAM added is in the range of 0.1~0.5mg / L, and after sedimentation in the sedimentation tank, part of the sediment and suspended matter are removed; S603, multi-stage filtration and impurity removal: the precipitated wastewater is filtered through quartz sand and ultrafiltration in turn, and then the calcium ions, fluoride ions and heavy metals are removed through ion exchange resin, and then through two-stage reverse osmosis, and finally EDI purification and desalination, so that the wastewater reaches ultrapure water standards.

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