Method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag

Abstract

The invention discloses a method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag, and relates to the technical field of non-ferrous metal carbonylation metallurgy, the method comprises the following steps: S1, hydrogen reduction and activation; s2, feeding into a high-pressure carbonylation reactor; and S3, efficient carbonylation. According to the method, the carbonylation slag is subjected to hydrogen reduction activation treatment, nickel protoxide and cobalt oxide are changed into simple substance nickel, the simple substance nickel is fed into a carbonylation reactor for carbonylation under the protection of reducing gas or inert gas after activation treatment, 95% of Ni, 85% of Fe and 80% of Co are carbonylated to enter a gas phase after carbonylation, bonding of cobalt and a platinum solid solution is broken through carbonylation, and the nickel-cobalt-cobalt-cobalt-cobalt alloy is obtained. Nickel protoxide is difficult to dissolve in various strong acids and oxidizing acids, and a foundation is laid for further separation of base metals and non-metallic element sulfur from precious metals to produce high-grade platinum concentrate.

Description

Technical Field

[0001] The present invention relates to the technical field of non-ferrous metal carbonylation metallurgy, and specifically discloses a method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag. Background Art

[0002] In the high-nickel matte beneficiation process, the nickel-copper alloy concentrate obtained by magnetic separation (i.e., primary alloy), as the main carrier mineral of precious metals after high-nickel matte separation, its subsequent treatment process is crucial for the extraction efficiency of precious metals. The existing process path is usually as follows: The primary alloy is blown in a Kaldo furnace - quenched with water to obtain a copper-nickel alloy, which is used as a carbonylation raw material for medium-pressure carbonylation treatment. During this process, about 90% of Ni, 60% of Fe, and 15% of Co are carbonylated into the gas phase, while the precious metals are enriched in the carbonylation slag. However, the platinum and palladium content in the carbonylation slag is only about 500 g / t, far from meeting the conditions for direct leaching and separation and purification. Therefore, it is necessary to first separate base metals such as Cu, Ni, Co, Fe and non-metallic element S, etc. In recent years, the controlled-potential electrolysis process has been applied as an advanced technology in China. This process has remarkable effects in removing base metals such as Cu, Ni, and Fe. After removing monomer sulfur, a concentrate with a platinum group metal grade of up to 5.5% can be produced, meeting the conditions for leaching precious metals by chlorination. However, it was found that when leaching platinum and palladium by chlorination leaching, the leaching rate of platinum and palladium is very low, especially the leaching rate of platinum is less than 50%. Through chemical analysis, it is found that this concentrate contains up to 30% cobalt and 10% nickel. Since cobalt forms a poorly soluble solid solution with platinum and has extremely strong inertness, it is not conducive to the dissolution by strong oxidants. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides a method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows: A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag, comprising the following steps: S1. Add the carbonylation slag into a rotary kiln for hydrogen reduction activation treatment. During the reduction activation treatment, an active reagent and H2 are mixed and then introduced into the rotary kiln to react with nickel oxide and cobalt oxide in the carbonylation slag, reducing the oxidized state to the sponge state; S2. When the temperature of the sponge metal drops to 50 - 60 °C, introduce a reducing gas or an inert gas into the rotary kiln, and the sponge metal is sent into a carbonylation reactor under the protection of the reducing gas or the inert gas; S3. Introduce CO into the carbonylation reactor. The temperature during the carbonylation reaction process is 180°C - 220°C. Introduce the mixed gas of Ni(CO)4, Fe(CO)5, Co(CO)8 and CO generated by the carbonylation reaction into the decomposer to produce magnetic materials of nickel-cobalt-iron in the micron or nano scale, which can be directly used as products. The carbonylation rates of Ni, Fe, and Co after carbonylation are 95%, 85%, and 80% respectively, breaking the bonding of the cobalt-platinum solid solution and eliminating the influence of the inertness of nickel oxide on subsequent leaching.

[0005] Further, in the step S1, the rotation speed of the rotary kiln is 2 - 3 r / min, and the temperature during the reaction process is 360°C - 390°C.

[0006] Further, in the step S1, the activation reagent is H2S gas, and the pressure after mixing with H2 is 0.15 MPa; Further, in the step S2, the reducing gas or inert gas is H2 or Ar.

[0007] The CO in the step S2, wherein the CO content is 97%, the H2 content is 1%, the CO2 content is 1%, and the N2 content is 1%.

[0008] Further, in the step S3, the pressure of CO is 24 - 26 MPa, and the preheating temperature is 160°C - 200°C.

[0009] The beneficial effects of the present invention are as follows: During the blowing process of the nickel-containing material primary alloy in the Kaldo furnace, part of the nickel and cobalt are oxidized, and the formed oxides are very inert, not easily dissolved by strong acids or even leached by oxidizing acids, and are also very difficult to be carbonylated. After being reduced by hydrogen and activated by hydrogen sulfide gas in the present invention, the nickel oxide and cobalt oxide are changed into elemental nickel, the surface activity is enhanced and the internal voids are increased, and nickel and cobalt are secondarily activated and have the ability to participate in carbonylation. After carbonylation, 95% of Ni, 85% of Fe, and 80% of Co are carbonylated into the gas phase. The carbonylation breaks the bonding of the cobalt-platinum solid solution and eliminates the influence of the inertness of nickel oxide on subsequent leaching. Subsequently, a concentrate with a platinum group metal content of 6.5% is produced, and the enrichment multiple reaches 120 times. The primary leaching rate of platinum and palladium by aqueous solution chlorination leaching reaches 85%, and the three-time leaching rate reaches 99%. In this way, it well connects the ammonium chloride precipitation separation and respective refining processes of platinum and palladium. The platinum refining adopts the ammonium chloride repeated precipitation method, and the palladium refining adopts the combined refining method of water-soluble palladium precipitation and diammonium dichloride complex palladium. Brief Description of the Drawings

[0010] Figure 1 It is the process flow chart of the present invention. Detailed Embodiments

[0011] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following descriptions, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0012] Example 1 The carbonylation slag contains 345 g / t of platinum, 165 g / t of palladium, 9.53% of nickel, 65.32% of copper, 1.86% of cobalt, and 14.58% of sulfur. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag, comprising the following steps: S1. Add the carbonylation slag into a rotary kiln for hydrogen reduction activation treatment. The rotation speed of the rotary kiln is 2 r / min, and the temperature during the reaction process is 360°C. During the reduction activation treatment, H2S gas and H2 are mixed and then introduced into the rotary kiln. The pressure after mixing is 0.15 MPa, and a reduction reaction occurs with nickel oxide and cobalt oxide in the carbonylation slag to reduce the oxidized state to the sponge state. S2. When the temperature of the sponge metal drops to 50°C, introduce Ar into the rotary kiln, and send the sponge metal into the carbonylation reactor under the protection of reducing gas or inert gas. S3. Introduce CO into the carbonylation reactor. The pressure of CO is 24 Mpa, the preheating temperature is 160°C, and the temperature during the carbonylation reaction process is 180°C. The mixed gas of Ni(CO)4, Fe(CO)5, Co(CO)8 and CO generated by the carbonylation reaction is introduced into the decomposer to produce micron-sized or nano-sized magnetic materials of nickel, cobalt and iron, which can be directly used as products. After carbonylation, the carbonylation rates of Ni, Fe, and Co are 95%, 85%, and 80% respectively, breaking the bonding of the cobalt-platinum solid solution and eliminating the influence of the inertness of nickel oxide on subsequent leaching.

[0013] After being treated by steps S1 - S3, the carbonylation slag produced contains 412 g / t of platinum, 201 g / t of palladium, 5.34% of nickel, 73.45% of copper, 0.53% of cobalt, and 17.62% of sulfur, creating conditions for the next separation of base metals.

[0014] Example 2 The carbonylation slag contains 358 g / t of platinum, 175 g / t of palladium, 8.73% of nickel, 64.82% of copper, 1.65% of cobalt, and 15.45% of sulfur.

[0015] A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag, comprising the following steps: S1. Add the carbonylation residue into a rotary kiln for hydrogen reduction activation treatment. The rotation speed of the rotary kiln is 2.5 r / min, and the temperature during the reaction process is 375 °C. During the reduction activation treatment, mix H2S gas and H2 and introduce them into the rotary kiln. The pressure after mixing is 0.15 MPa. A reduction reaction occurs with nickel oxide and cobalt oxide in the carbonylation residue, reducing the oxidized state to the sponge state; S2. When the temperature of the sponge metal drops to 55 °C, introduce Ar into the rotary kiln. The sponge metal is sent into the carbonylation reactor under the protection of a reducing gas or an inert gas; S3. Introduce CO into the carbonylation reactor. The pressure of CO is 25 Mpa, the preheating temperature is 180 °C, and the temperature during the carbonylation reaction process is 200 °C. Introduce the mixed gas of Ni(CO)4, Fe(CO)5, Co(CO)8 and CO generated by the carbonylation reaction into a decomposer to produce magnetic materials of micron-sized or nano-sized nickel, cobalt and iron, which can be directly used as products. The carbonylation rates of Ni, Fe, and Co after carbonylation are 95%, 85%, and 80% respectively, breaking the bonding of the cobalt-platinum solid solution and eliminating the influence of the inertness of nickel oxide on subsequent leaching.

[0016] After being treated by steps S1 - S3, the carbonylation residue contains 428 g / t of platinum, 210 g / t of palladium, 5.12% of nickel, 74.55% of copper, 0.45% of cobalt, and 18.62% of sulfur, creating conditions for the next separation of base metals.

[0017] Example 3 The carbonylation residue contains 362 g / t of platinum, 150 g / t of palladium, 8.5% of nickel, 63.52% of copper, 1.72% of cobalt, and 16.65% of sulfur.

[0018] A method for recovering platinum and palladium from a high-cobalt nickel-containing carbonylation residue, comprising the following steps: S1. Add the carbonylation residue into a rotary kiln for hydrogen reduction activation treatment. The rotation speed of the rotary kiln is 3 r / min, and the temperature during the reaction process is 390 °C. During the reduction activation treatment, mix H2S gas and H2 and introduce them into the rotary kiln. The pressure after mixing is 0.15 MPa. A reduction reaction occurs with nickel oxide and cobalt oxide in the carbonylation residue, reducing the oxidized state to the sponge state; S2. When the temperature of the sponge metal drops to 60 °C, introduce H2 into the rotary kiln. The sponge metal is sent into the carbonylation reactor under the protection of a reducing gas or an inert gas; S3. Introduce CO into the carbonylation reactor. The pressure of CO is 26 Mpa, the preheating temperature is 200 °C, and the temperature during the carbonylation reaction is 220 °C. Introduce the mixed gas of Ni(CO)4, Fe(CO)5, Co2(CO)8 and CO generated by the carbonylation reaction into the decomposer to produce magnetic materials of nickel, cobalt and iron at the micron or nanometer level, which can be directly used as products. After carbonylation, the carbonylation rates of Ni, Fe and Co are 95%, 85% and 80% respectively, breaking the bonding of the cobalt-platinum solid solution and eliminating the influence of the inertness of nickel oxide on subsequent leaching.

[0019] After being treated by steps S1 - S3, the platinum content in the carbonylation residue is 434 g / t, the palladium content is 180 g / t, the nickel content is 5.3%, the copper content is 73.03%, the cobalt content is 0.4%, and the sulfur content is 18.55%, creating conditions for the next separation of base metals.

[0020] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation on the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all variations and modifications that fall within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag, characterized in that, It includes the following steps: S1. Add carbonylation slag into a rotary kiln for hydrogen reduction activation treatment. During the reduction activation treatment, mix the active reagent and H2 and then introduce them into the rotary kiln to react with nickel oxide and cobalt oxide in the carbonylation slag, reducing the oxidized state to the sponge state; S2. When the temperature of the sponge metal drops to 50 - 60 °C, introduce reducing gas or inert gas into the rotary kiln, and send the sponge metal into the carbonylation reactor under the protection of the reducing gas or inert gas; S3. Introduce CO into the carbonylation reactor. The temperature during the carbonylation reaction is 180 °C - 220 °C. Introduce the mixed gas of Ni(CO)4, Fe(CO)5, Co(CO)8 and CO generated by the carbonylation reaction into the decomposer to produce magnetic materials of micron - level or nano - level nickel - cobalt - iron, which can be directly used as products. After carbonylation, the carbonylation rates of Ni, Fe, and Co are 95%, 85%, and 80% respectively, breaking the bonding of the cobalt - platinum solid solution and eliminating the influence of the inertness of nickel oxide on subsequent leaching.

2. The method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag according to claim 1, wherein: In step S1, the rotation speed of the rotary kiln is 2 - 3 r / min, and the temperature during the reaction process is 360 °C - 390 °C.

3. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag according to claim 1, characterized in that: In step S1, the activation reagent is H2S gas, and the pressure after mixing with H2 is 0.15 Mpa.

4. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag according to claim 1, characterized in that: In step S2, the reducing gas or inert gas is H2 or Ar.

5. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag according to claim 1, characterized in that: For the CO in step S2, the CO content is 97%, the H2 content is 1%, the CO2 content is 1%, and the N2 content is 1%.

6. A method for recovering platinum and palladium from high-cobalt nickel-containing carbonylation slag according to claim 1, characterized in that: In step S3, the pressure of CO is 24 - 26 MPa, and the preheating temperature is 160 °C - 200 °C.

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