Oxygen pressure ammonia leaching device and treatment method for molybdenum sulfide ore

Abstract

The invention relates to an oxygen pressure ammonia leaching device and treatment method for molybdenum sulfide ore, the oxygen pressure ammonia leaching device comprises a first vertical high-pressure kettle and at least two second vertical high-pressure kettles, and feed ports of the at least two second vertical high-pressure kettles are connected to a discharge port of the first vertical high-pressure kettle in parallel. The treatment method comprises the following steps: carrying out fine grinding on the molybdenum sulfide ore to be treated to obtain ore powder; the mineral powder and ammonia water are mixed for pulp mixing, and ore pulp is obtained; the ore pulp is input into a first vertical high-pressure kettle, steam and oxygen-enriched gas are introduced at the same time, and the temperature is increased; and inputting the heated ore pulp into at least two second vertical autoclaves, introducing steam and oxygen-enriched gas at the same time, carrying out oxygen pressure ammonia leaching, and sequentially carrying out temperature reduction, pressure reduction and solid-liquid separation to obtain a leachate. All the vertical high-pressure autoclaves of the oxygen pressure ammonia leaching device can operate stably, and the problem of potential safety hazards in production can be effectively solved.

Description

Technical Field

[0001] The invention relates to an oxygen-pressure ammonia leaching device and a treatment method for molybdenum sulfide ore, belonging to the field of hydrometallurgy. Background Art

[0002] Molybdenum, as a key rare and precious strategic metal, plays an indispensable role in the production of various special steels. Molybdenum and its alloys have good chemical properties and physical and chemical indicators, and are widely used in metallurgy, chemical industry, mechanical manufacturing, electronic products, aerospace and other fields. Molybdenite (molybdenum mainly exists in the form of MoS2) is the most widely used raw material for the production of ammonium molybdate in the molybdenum industry. At present, in industry, the main process of treating molybdenite to produce ammonium molybdate is oxidation roasting-ammonia leaching-acid precipitation. Among them, oxidation roasting generally uses a multi-chamber furnace or a brick kiln. The purpose of roasting is to desulfurize molybdenite and convert it into molybdenum trioxide that is easily leached by ammonia water. After the leachate is purified, acid precipitation is used to produce ammonium molybdate. This method has problems such as the molybdenum trioxide produced by roasting is easy to sublimate and lose, and it is easy to generate low eutectic materials to cause the material to sinter and affect desulfurization. The low-concentration SO2 flue gas produced by roasting is difficult to make acid, and the environmental governance cost is high.

[0003] To this end, molybdenum metallurgical researchers have carried out a lot of research in the direction of full hydrometallurgy and have made significant progress. At present, full hydrometallurgy is mainly divided into two methods: oxygen pressure water leaching and oxygen pressure alkali leaching. This method does not produce SO2 gas, can treat low-grade complex molybdenite, has a high molybdenum recovery rate, and can comprehensively recover associated valuable metals. Among them, oxygen pressure water leaching is to add water, convert molybdenite into molybdenum trioxide under oxygen pressure conditions, and then carry out alkali leaching, that is, the two processes of sulfur oxidation and molybdenum leaching are completed in two steps; oxygen pressure alkali leaching is to add alkali solution or ammonia water, and combine the two processes of sulfur oxidation and molybdenum leaching in molybdenite under oxygen pressure conditions into one step. In oxygen pressure alkali solution leaching, the alkali solution is not easy to volatilize, the temperature and pressure of the autoclave are easy to control, and the production safety is high. The disadvantage is that sodium ions enter the wastewater, resulting in high wastewater treatment costs; in oxygen pressure ammonia leaching, ammonia ions enter the wastewater and can be evaporated and recycled. The disadvantage is that ammonia ions are easy to volatilize, the temperature and pressure of the autoclave are not easy to control, and there are major production safety hazards. Therefore, the current oxygen-pressure ammonia leaching of molybdenite is carried out by intermittent operation of a high-pressure autoclave, which has the problems of low productivity and high energy consumption. Summary of the invention

[0004] In view of the shortcomings of the prior art, one of the objects of the present invention is to provide an oxygen-pressure ammonia leaching device for molybdenum sulfide ore with high safety; the second object of the present invention is to provide a method for treating molybdenum sulfide ore.

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] An oxygen-pressure ammonia leaching device for molybdenum sulfide ore comprises a first vertical autoclave and at least two second vertical autoclaves, wherein the feed ports of the at least two second vertical autoclaves are connected in parallel to the discharge port of the first vertical autoclave.

[0007] Thus, the molybdenum sulfide ore and ammonia water mixed slurry to be treated can be input (or the molybdenum sulfide ore slurry to be treated and ammonia water are directly input) into the first vertical autoclave, and the mixed material in the first vertical autoclave is rapidly heated (due to the slow reaction speed in the early stage, the heating rate can be accelerated while ensuring safety, and the molybdenum sulfide ore particles can be initially reacted and dissociated, and the ammonia water can also be fully infiltrated into the particles, laying the foundation for subsequent reactions); then, the heated slurry can be simultaneously and continuously input into multiple second vertical autoclaves in a parallel flow manner, and at this time, only a short heating and heating or direct heating is required to reach the target oxygen pressure ammonia leaching conditions, which is conducive to the smooth and efficient leaching process; moreover, the slurry enters multiple second vertical autoclaves, and the slurry flow rate in each second vertical autoclave is small, and the temperature and pressure are easy to control or maintain at the target value, which is conducive to the stable operation of the second vertical autoclave. Therefore, during operation, each vertical autoclave of the oxygen pressure ammonia leaching device of the present invention can operate smoothly, which can effectively solve the problem of production safety hazards, and can achieve continuous production, which is conducive to improving production efficiency.

[0008] Furthermore, it also includes a first pipeline, which is connected to the feed inlet of the first vertical autoclave. Preferably, a pump is provided on the first pipeline.

[0009] Furthermore, it also includes a second pipeline, and the feed inlets of the second vertical autoclaves are connected in parallel to the second pipeline.

[0010] Furthermore, it also includes a flash tank, and the discharge port of each second vertical autoclave is connected in parallel to the feed port of the flash tank; preferably, it also includes a third pipeline, and the discharge port of each second vertical autoclave is connected in parallel to the third pipeline, and the third pipeline is connected to the flash tank.

[0011] Furthermore, the number of the second vertical autoclaves is 3-7, preferably 4-5.

[0012] Furthermore, it also includes a fourth pipeline, an oxygen delivery pipe and a steam delivery pipe. An air inlet is provided at the bottom of the vertical autoclave. The air inlet of each vertical autoclave is connected in parallel to the fourth pipeline. The fourth pipeline is connected to the oxygen delivery pipe, and the fourth pipeline is connected to the steam delivery pipe.

[0013] Furthermore, a first valve is provided at the feed inlet of each vertical autoclave, and a second valve is provided at the discharge outlet of each vertical autoclave.

[0014] Furthermore, the air inlet of each vertical autoclave is provided with a third valve.

[0015] As a result, the flow of slurry, oxygen-rich gas, and steam entering the relevant vertical autoclaves, as well as the temperature, pressure, heating time, or leaching time and other parameters therein can be conveniently and more accurately controlled, which helps to further reduce safety hazards and improve the leaching effect. In addition, by switching the relevant valves, part of the second vertical reactor can be selectively put into operation or stopped, and the slag and scale in part of the second vertical reactor can be conveniently cleaned or repaired, while the oxygen pressure ammonia leaching device can still be in normal production operation, which helps to increase production capacity and better meet the needs of industrial production.

[0016] Optionally, the volume of the first vertical autoclave is smaller than the volume of the second vertical autoclave.

[0017] Based on the same inventive concept, the present invention also provides a method for treating molybdenum sulfide ore, which is carried out using the oxygen pressure ammonia leaching device as described above; comprising the following steps:

[0018] S1. Finely grinding the molybdenum sulfide ore to be processed to obtain ore powder;

[0019] S2, mixing the mineral powder with ammonia water to obtain mineral slurry;

[0020] S3, continuously inputting the slurry into a first vertical autoclave, and simultaneously introducing steam and oxygen-rich gas to increase the temperature; then continuously inputting the heated slurry into at least two second vertical autoclaves, and simultaneously introducing steam and oxygen-rich gas to perform oxygen-pressure ammonia leaching, and then successively performing temperature and pressure reduction and solid-liquid separation to obtain leached residue and leaching liquid;

[0021] Among them, the oxygen pressure ammonia immersion time is longer than the heating time.

[0022] Further, the D90 of the mineral powder is less than 30um; preferably, the molybdenum sulfide ore is molybdenite;

[0023] Alternatively, in S2, the mass ratio of mineral powder to ammonia water is 1:6-9, and the concentration of ammonia water is 8-14wt%;

[0024] Alternatively, in S3, the temperature is raised to 160-200°C for 0.3-0.4h; the temperature of oxygen-pressure ammonia immersion is 180-200°C, the total pressure is 2-2.6MPa, and the oxygen-pressure ammonia immersion time is 6-8h.

[0025] Furthermore, the molybdenum sulfide ore contains Cu, and the leaching solution is subjected to organic extraction to recover copper.

[0026] Optionally, the extractant used for organic extraction is an alkane or an alkene, with a volume concentration of 10-20%, and a relative ratio (O / A) of (0.5-1) / 2. Optionally, copper is recovered by extraction electrowinning, and copper electrowinning waste liquid is used as a back extractant, with a relative ratio (O / A) of (1-3) / 1.

[0027] Optionally, the Cu content in the molybdenum sulfide ore is less than 5wt%, further 1-3wt%.

[0028] Further, a strong acid is added to the leachate for acid precipitation. After the pH value of the leachate reaches 2-3, solid-liquid separation is performed, and washing (optionally water washing) is performed to obtain ammonium molybdate; preferably, the strong acid is nitric acid. Optionally, the acid precipitation liquid obtained by solid-liquid separation is evaporated and concentrated to obtain ammonium salts (ammonium sulfate and ammonium nitrate).

[0029] Furthermore, the oxygen concentration of the oxygen-rich gas is 90 vol% or more, further 95 vol% or more, and further 99 vol%.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) By adopting the oxygen pressure ammonia leaching device of the present invention, the temperature of the molybdenum sulfide ore slurry in a first vertical autoclave can be quickly raised to or close to the reaction temperature. In the initial stage of the reaction, the reaction of ammonia ions is not intense and is easy to control, so a faster heating rate can also be adopted; the heated slurry then enters multiple second vertical autoclaves in a parallel flow manner, and stable leaching can be achieved by maintaining the temperature and pressure or only slightly raising the temperature. That is, the "small flow and long cycle" method can well control the degree of ammonia ion reaction, and the temperature control can keep each vertical autoclave running smoothly, thereby solving the problem of production safety hazards.

[0032] (2) The present invention completes the two steps of oxygen pressure and ammonia leaching in the same device, which helps to streamline the processing equipment and shorten the process. At the same time, it can achieve continuous production operation, improve production efficiency and reduce energy consumption.

[0033] (3) The oxygen-pressure ammonia leaching of the present invention has a good leaching effect, with a molybdenum leaching rate of more than 98% and a copper leaching rate of more than 94%. In addition, ammonium sulfate and ammonium nitrate products can be produced as by-products, which is highly efficient and environmentally friendly, and has good comprehensive recovery benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of a method for processing molybdenum sulfide ore.

[0035] Figure 2 The present invention is a simplified structural diagram of an oxygen-pressure ammonia leaching treatment device for molybdenum sulfide ore. DETAILED DESCRIPTION

[0036] The present invention will be described in detail below in conjunction with the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. For the convenience of description, the words "upper", "lower", "left" and "right" appearing in the following only indicate that the upper, lower, left and right directions are consistent with the drawings themselves, and do not limit the structure. Unless otherwise specified, the relevant percentages are all mass percentages.

[0037] Example 1

[0038] See also Figure 2 The oxygen-pressure ammonia leaching device for molybdenum sulfide ore of this embodiment includes a first vertical autoclave 2 and four second vertical autoclaves 3, and the feed ports of the four second vertical autoclaves 3 are connected in parallel to the discharge port of the first vertical autoclave 2.

[0039] The first pipeline 5 is also included. The first pipeline 5 is connected to the feed port of the first vertical autoclave 2 . A pump 1 is provided at the inlet end of the first pipeline 5 .

[0040] The system further comprises a second pipeline 6 , to which the feed inlets of the second vertical autoclaves 3 are connected in parallel.

[0041] It also includes a flash tank 4 and a third pipeline 7. The discharge ports of the second vertical autoclaves 3 are connected in parallel to the third pipeline 7. The third pipeline 7 is connected to the flash tank 4. A sixth valve 13 is provided at the feed port of the flash tank.

[0042] It also includes a fourth pipeline 8, an oxygen delivery pipe 9 and a steam delivery pipe 10. The bottom of the vertical autoclave is provided with an air inlet, and the air inlets of each vertical autoclave are connected in parallel to the fourth pipeline 8. The outlet ends of the oxygen delivery pipe 9 and the outlet ends of the steam delivery pipe 10 are connected in parallel to the inlet end of the fourth pipeline 8. The oxygen delivery pipe 9 is provided with a fourth valve, and the steam delivery pipe 10 is provided with a fifth valve.

[0043] The feed inlet of each vertical autoclave is provided with a first valve, the discharge port of each vertical autoclave is provided with a second valve, the air inlet of each vertical autoclave is provided with a third valve, and a stirring mechanism is provided in each vertical autoclave.

[0044] The total volume of a first vertical autoclave with a volume of 1 liter (as a heating autoclave) and four second vertical autoclaves with a volume of 5 liters (as a heat preservation autoclave, each with water cooling) is calculated (1+4x5=21 liters). 0.5 kg / h of molybdenite (Mo: 45.2%, S: 32.1%, Fe: 3.8%, Cu: 3.4%) is taken, the molybdenite is finely ground to D (90) < 30 um, 3 L / h of ammonia water with a concentration of 12% is added, and the slurry is mixed (liquid-solid mass ratio 6:1), and the adjusted slurry is continuously pumped into a first vertical autoclave, and steam and oxygen-rich gas (oxygen content 99 vol%) are introduced at the same time. Control The steam and oxygen-enriched gas are introduced at a rate such that the heating time is 0.33h, that is, the slurry is heated to 180°C; the heated slurry is continuously fed into 4 second vertical autoclaves in a parallel flow manner, and steam and oxygen-enriched gas (oxygen content 99vol%) are introduced at the same time to carry out oxygen-pressure ammonia leaching, and the temperature is controlled at 180°C, the pressure is 2.0MPa, and the reaction time is 6.67h. After the reaction is completed, the slurry is cooled and depressurized, and liquid-solid separation is performed to produce 3L / h of leaching solution (Mo: 74.43g / L, Cu: 5.34g / L). According to calculation, the molybdenum leaching rate is 98.8%, and the copper leaching rate is 94.2%. The leaching solution is used to recover copper by extraction electrowinning, and nitric acid is added to the copper extraction residual solution for acid precipitation, and the end point pH is controlled to be 2 to produce ammonium molybdate.

[0045] Example 2

[0046] The oxygen-pressure ammonia leaching device as described in Example 1 was used. Specifically, the total volume of a 1-liter first vertical autoclave and four 5-liter second vertical autoclaves (single water-cooled) was calculated (1+4x5=21 liters). 0.4 kg / h of molybdenite (Mo: 41.2%, S: 33.3%, Fe: 6.8%, Cu: 2.2%) was taken, the molybdenite was finely ground to D (90) < 30 um, 3.2 L / h of 10% ammonia water was added, and the slurry was mixed (liquid-solid mass ratio 8: 1), and the adjusted slurry was continuously pumped into a first vertical autoclave, and steam and oxygen-rich gas (oxygen content 99 vol%) were introduced at the same time. The steam and oxygen-rich gas introduction rates were controlled so that The heating time is 0.31h, that is, the slurry is heated to 200°C; the heated slurry is continuously input into 4 second vertical autoclaves in a parallel flow manner, and steam and oxygen-rich gas (oxygen content 99vol%) are introduced at the same time to carry out oxygen-pressure ammonia leaching, and the temperature is controlled at 200°C, the pressure is 2.6MPa, and the reaction time is 6.25h. After the reaction is completed, the slurry is cooled and depressurized, and liquid-solid separation is performed to produce 3.2L / h of leaching solution (Mo: 51.04g / L, Cu: 2.61g / L), the molybdenum leaching rate is 99.1%, and the copper leaching rate is 94.8%. The leaching solution adopts extraction electrowinning method to recover copper, and nitric acid is added to the residual solution of copper extraction for acid precipitation, and the end point pH is controlled to be 3 to produce ammonium molybdate.

[0047] Example 3

[0048] The oxygen-pressure ammonia leaching device as described in Example 1 was used. Specifically, based on the total volume of a 1-liter first vertical autoclave and four 5-liter second vertical autoclaves (single water-cooled) (1+4x5=21 liters), 0.5 kg / h of molybdenite (Mo: 44.4%, S: 34.1%, Fe: 4.8%) was taken, the molybdenite was finely ground to d(90) <30 um, 3 L / h of ammonia water with a concentration of 12% was added, and the slurry was mixed (liquid-solid mass ratio 6:1), and the adjusted slurry was continuously pumped into a first vertical autoclave, and steam and oxygen-rich gas (oxygen content 99 vol%) were introduced at the same time. The steam and oxygen-rich gas introduction rates are controlled so that the heating time is 0.33h, that is, the slurry is heated to 180°C; the heated slurry is continuously fed into 4 second vertical autoclaves in a parallel flow manner, and steam and oxygen-rich gas (oxygen content 99vol%) are introduced at the same time to carry out oxygen-pressure ammonia leaching, and the temperature is controlled to be 180°C, the pressure is 2.0MPa, and the reaction time is 6.67h. After the reaction is completed, the slurry is cooled and reduced in temperature and pressure, and liquid-solid separation is performed to produce 3L / h of leaching solution (Mo: 73.26g / L), and the molybdenum leaching rate is 99%. Nitric acid is added to the leaching solution for acid precipitation, and the end point pH is controlled to be 2 to produce ammonium molybdate.

[0049] Example 4

[0050] The oxygen-pressure ammonia leaching device as described in Example 1 was used. Specifically, based on the total volume of a 1-liter first vertical autoclave and four 5-liter second vertical autoclaves (single water-cooled) (1+4x5=21 liters), 0.4 kg / h of molybdenite (Mo: 42.8%, S: 35.2%, Fe: 5.9%) was taken, the molybdenite was finely ground to d(90) <30 um, 3.2 L / h of 10% ammonia water was added, and the slurry was mixed (liquid-solid mass ratio 8:1), and the adjusted slurry was continuously pumped into a first vertical autoclave, and steam and oxygen-rich gas (oxygen content 99 vol%) were introduced at the same time, and the control The steam and oxygen-rich gas are introduced at a rate such that the heating time is 0.31 h, that is, the slurry is heated to 200° C.; the heated slurry is continuously fed into four second vertical autoclaves in a parallel flow manner, and steam and oxygen-rich gas (oxygen content 99 vol%) are introduced at the same time to carry out oxygen-pressure ammonia leaching, and the temperature is controlled at 200° C., the pressure is 2.6 MPa, and the reaction time is 6.25 h. After the reaction is completed, the slurry is cooled and depressurized, and liquid-solid separation is performed to produce 3.2 L / h of leaching solution (Mo: 53.13 g / L), and the molybdenum leaching rate is 99.3%. Nitric acid is added to the leaching solution for acid precipitation, and the end point pH is controlled to be 3, and ammonium molybdate is produced.

[0051] Comparative Example 1

[0052] Example 1 was repeated, except that the first vertical autoclave was discarded and the adjusted slurry was directly fed into four second vertical autoclaves in parallel flow.

[0053] The results showed that the molybdenum leaching rate was only 89.6%, and the copper leaching rate was only 86.8%. The possible reason is that during the oxygen-pressure ammonia leaching of molybdenum sulfide ore, alkalinity affects the reaction efficiency of ammonia and minerals. The alkalinity of the leachate from the first vertical autoclave is low, and there is more ammonia in gaseous form. The gaseous ammonia in the following four second vertical autoclaves is less (high alkalinity). Ammonia water can form a stable combination with molybdenum and copper ions, which helps to effectively dissolve molybdenum and copper. If the first vertical autoclave is abandoned and the adjusted ore slurry is directly input into the four second vertical autoclaves in parallel flow, during the heating process, excessive release of ammonia will occur, the solubility of ammonia will decrease (low alkalinity), and the reaction rate of minerals and ammonia will slow down, resulting in molybdenum and copper leaching rates of less than 90%, and increased safety hazards.

[0054] The contents explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

Claims

1. An oxygen-pressure ammonia leaching device for molybdenum sulfide ore, characterized in that: It comprises a first vertical autoclave (2) and at least two second vertical autoclaves (3), wherein the feed ports of the at least two second vertical autoclaves (3) are connected in parallel to the discharge port of the first vertical autoclave (2).

2. The oxygen pressure ammonia leaching device according to claim 1, characterized in that: The invention also comprises a first pipeline (5), wherein the first pipeline (5) is connected to a feed inlet of the first vertical autoclave (2). Preferably, a pump (1) is provided on the first pipeline (5).

3. The oxygen-pressure ammonia leaching device according to claim 1 or 2, characterized in that: It also comprises a second pipeline (6), and the feed inlets of each second vertical autoclave (3) are connected in parallel to the second pipeline (6).

4. The oxygen-pressure ammonia leaching device according to claim 1 or 2, characterized in that: The method further comprises a flash tank (4), wherein the discharge port of each second vertical autoclave (3) is connected in parallel to the feed port of the flash tank (4); preferably, the method further comprises a third pipeline (7), wherein the discharge port of each second vertical autoclave (3) is connected in parallel to the third pipeline (7), and the third pipeline (7) is in communication with the flash tank (4).

5. The oxygen-pressure ammonia leaching device according to claim 1 or 2, characterized in that: The vertical autoclave further comprises a fourth pipeline (8), an oxygen delivery pipe (9) and a steam delivery pipe (10); an air inlet is provided at the bottom of the vertical autoclave; the air inlets of the vertical autoclaves are connected in parallel to the fourth pipeline (8); the fourth pipeline (8) is connected to the oxygen delivery pipe (9); and the fourth pipeline (8) is connected to the steam delivery pipe (10).

6. The oxygen-pressure ammonia leaching device according to claim 1 or 2, characterized in that: The feed inlet of each vertical autoclave is provided with a first valve, and the discharge port of each vertical autoclave is provided with a second valve.

7. A method for treating molybdenum sulfide ore, characterized in that: The method is carried out using the oxygen pressure ammonia leaching device as described in any one of claims 1 to 6; comprising the following steps: S1. Finely grinding the molybdenum sulfide ore to be processed to obtain ore powder; S2, mixing the mineral powder with ammonia water to obtain mineral slurry; S3, inputting the slurry into a first vertical autoclave (2), introducing steam and oxygen-rich gas at the same time, and heating the slurry; then inputting the heated slurry into at least two second vertical autoclaves (3), introducing steam and oxygen-rich gas at the same time, After oxygen-pressure ammonia leaching, the temperature and pressure are lowered and the solid-liquid separation is performed in sequence to obtain leaching residue and leaching liquid; Among them, the oxygen pressure ammonia immersion time is longer than the heating time.

8. The processing method according to claim 7, characterized in that: The D90 of the mineral powder is less than 30um; preferably, the molybdenum sulfide ore is molybdenite; Alternatively, in S2, the mass ratio of mineral powder to ammonia water is 1:6-9, and the concentration of ammonia water is 8-14wt%; Alternatively, in S3, the temperature is raised to 160-200°C for 0.3-0.4h; the temperature of oxygen-pressure ammonia immersion is 180-200°C, the total pressure is 2-2.6MPa, and the oxygen-pressure ammonia immersion time is 6-8h.

9. The processing method according to claim 7, characterized in that: The molybdenum sulfide ore contains Cu, and the leaching solution is subjected to organic extraction to recover copper.

10. The processing method according to claim 7, characterized in that: A strong acid is added to the leachate for acid precipitation. After the pH value of the leachate reaches 2-3, the solid-liquid is separated and washed to obtain ammonium molybdate. Preferably, the strong acid is nitric acid.

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