A method for producing sodium oxide precursors by direct spray pyrolysis of copper-manganese slag leachate

Abstract

The present invention relates to the technical field of sodium battery materials, and discloses a method for producing sodium-electrode oxide precursors by direct spray pyrolysis of copper-manganese slag leachate. The method comprises: immersing the copper-manganese slag produced by nickel-cobalt smelting into a high-purity leaching tank with acid to obtain a leachate containing Cu and Mn; the leachate elements do not need to be separated, and elements such as Ni and Fe are added according to the molar ratio of the elements required for the sodium-electrode material, and the leachate is directly atomized by a carrier gas and sent to a spray pyrolysis furnace, where a sodium-electrode oxide precursor is obtained by a one-step process of evaporation, drying, and high-temperature pyrolysis; the tail gas discharged from the pyrolysis furnace is absorbed by an absorption tower and then returned to the leaching system for reuse, and the waste heat is used to heat the leachate through a heat exchanger. The present invention realizes the production of sodium-electrode oxide precursors by direct spray pyrolysis of copper-manganese slag leachate, shortens the process flow, improves production efficiency, and reduces production costs.

Description

Technical Field

[0001] The invention relates to the technical field of sodium battery materials, and in particular to a method for producing a sodium battery oxide precursor by directly spraying and pyrolyzing a copper-manganese slag leachate. Background Art

[0002] With the development of nickel-cobalt industry, more and more copper-manganese slag is produced in nickel smelting. There is no better comprehensive utilization method for copper-manganese slag. Traditionally, most of it is stored and treated, resulting in resource waste and environmental problems. Copper-manganese slag contains a large amount of Cu 2+ and Mn 2+ , a small amount of Ni 2+ and Fe 2+ Valuable metals can be recovered and reused from copper-manganese slag, which has good economic benefits.

[0003] Currently, the recycling of copper-manganese slag includes pyrometallurgical and hydrometallurgical processes. The traditional pyrometallurgical process recovers copper, manganese and other metals through high-temperature smelting, but it suffers from high metal loss rates and the tendency of manganese to enter the slag again, resulting in poor economic and environmental performance. The hydrometallurgical process uses a step-by-step precipitation method through slurrying and leaching, using different precipitants or reducing agents to separate and recover metals and extract the valuable metal ions. However, this process is lengthy and costly.

[0004] Therefore, how to comprehensively utilize copper-manganese slag in an efficient, environmentally friendly and low-cost manner has become a core problem that needs to be overcome in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for producing a sodium oxide precursor by directly spraying and pyrolyzing a copper-manganese slag leachate.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for producing a sodium oxide precursor by direct spray pyrolysis of copper-manganese slag leachate, wherein the chemical formula of the sodium oxide is Ni 1-x-y-z Fe x Mn y Cu z O2, where 0<x<1, 0<y<1, 0<z<1, 0<x+y+z<1;

[0008] The method comprises the following steps:

[0009] S1: Immerse the copper-manganese slag produced by nickel smelting in a high-purity leaching tank with acid to obtain a leachate containing Cu and Mn;

[0010] S2: The leachate is supplemented with Cu, Mn, Ni, and Fe elements according to the molar percentage of the elements required for the sodium electrode material to prepare the metal solution required for the sodium electrode;

[0011] S3: The replenished leachate is atomized by a carrier gas and sent into a spray pyrolysis furnace, where it is evaporated, dried, and pyrolyzed at high temperature to obtain a sodium oxide precursor;

[0012] S4: The tail gas discharged from the spray pyrolysis furnace is absorbed and purified by an absorption tower to form recovered acid. When the concentration of the recovered acid reaches the standard, the recovered acid is returned to the high-purity leaching tank in S1 for reuse; the waste heat in the tail gas is absorbed by a heat exchanger and used to heat the leachate before entering the spray pyrolysis furnace.

[0013] In the above scheme, in S1, the nickel smelting slag contains a large amount of Cu 2+ and Mn 2+ ions, a small amount of Ni 2+ and Fe 2+ ions, Cu after leaching with high-purity acid 2+ The ion concentration is 25-35g / L, Mn 2+ The ion concentration is 100-120g / L, Fe 2+ Ion concentration <0.5g / L, Ni 2+ The ion concentration is extremely low.

[0014] In the above scheme, in S2, the "metal solution required for sodium electrolysis" means a solution that meets the ratio of elements in sodium electrolysis oxides. 2+ and Fe 2+ The lower ion concentration leads to Cu 2+ and Mn 2+ The ion concentration does not meet the requirements of the spray pyrolysis metal solution. Therefore, it is necessary to add supplementary raw materials to the leachate according to the molar percentage to adjust the ion concentration of each element. The supplementary raw materials for Mn, Cu, Ni, and Fe include nitrates, sulfates, or chlorides corresponding to each element.

[0015] In the above solution, in S4, the tail gas absorption liquid is selected from deionized water or distilled water, or a mixture of the two, preferably deionized water. The principle and structure of the tail gas absorption tower are commonly used in the environmental protection industry and will not be described in detail in this case.

[0016] In a further technical solution, in S1, the acid is sulfuric acid, hydrochloric acid or nitric acid, with a concentration of 80-120 g / L and a temperature of 70-80°C.

[0017] In a further technical solution, in S1, the solid-to-liquid ratio of the copper-manganese slag to the acid is 1:(3-6), preferably 1:4. The immersion time in the acid solution is 5-10 hours, preferably 7-10 hours. The copper-manganese slag is in powder form with a particle size of 1-500 μm.

[0018] In a further technical solution, in S2, the ion concentration in the leaching solution after replenishment is 1-5 mol / L, which is the sum of the concentrations of the four metal ions of Ni, Fe, Mn, and Cu; and the temperature of the leaching solution is 30-50°C.

[0019] In a further technical solution, in S3, the carrier gas is compressed air, nitrogen or oxygen, and the carrier gas flow rate is 20-40m³ / H.

[0020] In a further technical solution, in S3, the evaporation temperature is 300-400°C, the drying temperature is 500-600°C, and the pyrolysis temperature is 700-900°C.

[0021] In a further technical solution, in S4, the recovered acid concentration meets the standard requirement of 80-120 g / L. The system can be configured to monitor the recovered acid concentration every 24 hours. When the concentration reaches 80-120 g / L, the recovered acid is returned to the high-purity leaching tank for reuse, while the absorption tower is replenished with tail gas absorption liquid. If the concentration is lower than 80-120 g / L, it needs to be concentrated or blended with a higher-concentration acid of the same type, preferably blending. If the concentration is higher than 80-120 g / L, it needs to be diluted with deionized or distilled water.

[0022] In a further technical solution, in S1, the acid is nitric acid; and in S2, the raw material used for replenishing is nitrate.

[0023] The terms “include,” “including,” and “have” used in this document are open-ended terms, meaning including but not limited to.

[0024] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0025] The working principle and advantages of the present invention are as follows:

[0026] The present invention addresses the problems of long process flow and high cost in the existing extraction and utilization of valuable metal elements in copper-manganese slag, and provides a method for producing sodium oxide precursors by directly spraying and pyrolyzing copper-manganese slag leachate. The method does not require separation of valuable metal elements and can produce sodium oxide precursors in one step.

[0027] The present invention aims to reduce the Cu in nickel smelting slag to a minimum with the shortest process, the lowest cost and the highest quality. 2+ and Mn 2+ The valuable metal ions are leached out, eliminating the element separation step and directly transforming it into a qualified product by preparing the sodium oxide precursor through spray pyrolysis.

[0028] The present invention uses acid immersion to remove Cu in nickel smelting slag. 2+ and Mn 2+ Compared with traditional metal extraction methods, ion leaching has a shorter process and lower cost.

[0029] The present invention prepares the leaching solution into a sodium metal salt solution, and the Cu 2+ and Mn 2+ ions to prepare qualified sodium oxides and reduce Cu 2+ and Mn 2+ The loss when ions are processed separately makes the energy and cost control optimal.

[0030] The tail gas generated in the process of the present invention is absorbed by an absorption tower and can be reused, thereby reducing the emission of harmful substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a process flow chart of various embodiments of the present invention;

[0032] Figure 2 This is a scanning electron microscope image of the spray pyrolysis sodium oxide precursor of Example 1 of the present invention;

[0033] Figure 3 This is a scanning electron microscope image of the spray pyrolysis sodium oxide precursor of Example 2 of the present invention;

[0034] Figure 4 This is a scanning electron microscope image of the spray pyrolysis sodium oxide precursor of Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0036] Embodiments: After understanding the embodiments of this case, skilled persons may make changes and modifications based on the techniques taught in this case without departing from the spirit and scope of this case.

[0037] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms.

[0038] Example 1: Example 1 of the present invention discloses a method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate, such as Figure 1 As shown, the following steps are included:

[0039] S1: Immerse 2000kg of nickel smelting slag in a hydrochloric acid solution with a concentration of 90g / L and a volume of 8m³ for 5 hours at a temperature of 30°C.

[0040] S2: Detect the concentration of Cu and Mn ions in the high-purity immersion solution. Based on the test results, add nickel chloride and ferric chloride to prepare a mixed solution with a Ni:Fe:Mn:Cu molar percentage of 25:33:33:9 and a concentration of 2 mol / L. The temperature is raised to 40°C.

[0041] S3: The replenished leachate is fed into a spray pyrolysis furnace at a carrier gas flow rate of 25 m³ / h. The evaporation, drying, and pyrolysis temperatures are 350°C, 550°C, and 800°C, respectively, to obtain a sodium oxide precursor.

[0042] S4: The tail gas generated after the thermal decomposition of the sodium metal salt solution is collected in the absorption tower for 24 hours, the hydrochloric acid concentration is tested, and then returned to the reuse storage tank.

[0043] The prepared sodium oxide precursor was tested and characterized, and the physical and chemical data were as follows: Figure 2 As shown in Table 1, the prepared positive electrode materials were subjected to electrochemical performance tests, see Table 1.

[0044] Example 2: Example 2 of the present invention discloses a method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate, such as Figure 1 As shown, the following steps are included:

[0045] S1: Immerse 2000kg of nickel smelting slag in a nitric acid solution with a concentration of 90g / L and a volume of 8m³ for 5 hours at a temperature of 30°C.

[0046] S2: Detect the concentration of Cu and Mn ions in the high-purity immersion solution. Based on the test results, add nickel nitrate and ferric nitrate to prepare a mixed solution with a Ni:Fe:Mn:Cu molar percentage of 25:33:33:9 and a concentration of 2 mol / L. The temperature is raised to 40°C.

[0047] S3: The replenished leachate is fed into a spray pyrolysis furnace at a carrier gas flow rate of 25 m³ / h. The evaporation, drying, and pyrolysis temperatures are 350°C, 450°C, and 600°C, respectively, to obtain a sodium oxide precursor.

[0048] S4: The tail gas generated after the thermal decomposition of the sodium metal salt solution is collected in the absorption tower for 24 hours, the hydrochloric acid concentration is tested, and then returned to the reuse storage tank.

[0049] The prepared sodium oxide precursor was tested and characterized, and the physical and chemical data were as follows: Figure 3 As shown in Table 1, the prepared positive electrode materials were subjected to electrochemical performance tests, see Table 1.

[0050] Example 3: Example 3 of the present invention discloses a method for producing a sodium oxide precursor by direct spray pyrolysis of copper-manganese slag leachate, such as Figure 1 As shown, the following steps are included:

[0051] S1: Immerse 2000kg of nickel smelting slag in a 90g / L sulfuric acid solution with a volume of 8m³ for 5 hours at a temperature of 30°C.

[0052] S2: Detect the concentration of Cu and Mn ions in the high-purity immersion solution. Based on the test results, add nickel sulfate and ferric sulfate to prepare a mixed solution with a Ni:Fe:Mn:Cu molar percentage of 25:33:33:9 and a concentration of 2 mol / L. The temperature is raised to 40°C.

[0053] S3: The replenished leachate is fed into a spray pyrolysis furnace at a carrier gas flow rate of 25 m³ / h. The evaporation, drying, and pyrolysis temperatures are 350°C, 750°C, and 900°C, respectively, to obtain a sodium oxide precursor.

[0054] S4: The tail gas generated after the thermal decomposition of the sodium metal salt solution is collected in the absorption tower for 24 hours, the hydrochloric acid concentration is tested, and then returned to the reuse storage tank.

[0055] The prepared sodium oxide precursor was tested and characterized, and the physical and chemical data are shown in Table 1. The prepared positive electrode material was subjected to electrochemical performance testing, as shown in Table 1.

[0056] Comparative Example 1

[0057] S1: Prepare a metal salt solution with a molar percentage of 25:33:33:9 using nickel chloride, ferric chloride, manganese chloride, and copper chloride. The concentration is 2 mol / L and the temperature is raised to 40°C.

[0058] S2: The prepared sodium metal salt solution is fed into the spray pyrolysis furnace at a carrier gas flow rate of 25 m³ / H. The evaporation, drying and pyrolysis temperatures are 350°C, 550°C and 800°C respectively to obtain a sodium oxide precursor.

[0059] The prepared sodium oxide precursor was tested and characterized, and the physical and chemical data were as follows: Figure 4 As shown in Table 1, the prepared positive electrode materials were subjected to electrochemical performance tests, see Table 1.

[0060] Comparative Example 2

[0061] S1: Prepare a metal salt solution with a molar percentage of 25:33:33:9 using nickel nitrate, iron nitrate, manganese nitrate, and copper nitrate. The concentration is 2 mol / L and the temperature is raised to 40°C.

[0062] S2: The prepared sodium metal salt solution is fed into the spray pyrolysis furnace at a carrier gas flow rate of 25 m³ / H. The evaporation, drying and pyrolysis temperatures are 350°C, 450°C and 600°C respectively to obtain a sodium oxide precursor.

[0063] The prepared sodium oxide precursor was tested and characterized, and the physical and chemical data are shown in Table 1. The prepared positive electrode material was subjected to electrochemical performance testing, as shown in Table 1.

[0064] Table 1 Indicators of sodium oxide precursors

[0065]

[0066] Comparing Example 1, Example 2, and Example 3, different acids were used to leach the copper-manganese slag. The nitrate-based sodium oxide precursor had the smallest primary particle size and the largest BET, indicating that the nitric acid-based precursor was more active. The chloride-based precursor had the largest primary particle size, the smallest BET, and the lower precursor activity. The sulfuric acid-based precursor data was in the middle, while the other indicators were basically the same. As can be seen from Table 1, the cathode material prepared in Example 2 had the highest specific capacity.

[0067] Comparing Example 1 with Comparative Example 1, the precursor indicators, electrochemical specific capacity and first effect are basically consistent, indicating that the leachate after immersion and replenishment of nickel-cobalt smelting slag is consistent with the precursor performance of the solution prepared with chloride salt after spray pyrolysis, further illustrating that the one-step preparation of sodium electric materials with copper-manganese slag leachate will not reduce product indicators and electrochemical performance.

[0068] Comparing Example 2 with Comparative Example 2, the precursor indicators, electrochemical specific capacity and first effect are basically consistent, indicating that the leachate after immersion and replenishment of nickel-cobalt smelting slag is consistent with the precursor performance of the solution prepared with nitrate after spray pyrolysis, further illustrating that the one-step preparation of sodium electrical materials using copper-manganese slag leachate will not reduce product indicators and electrochemical performance.

[0069] In summary, the copper-manganese slag leachate of the present invention does not need to be separated and recovered for valuable metal elements, and the spray pyrolysis method is directly used to produce sodium oxide precursors, which can significantly shorten the process flow of valuable metal recovery and reuse. The produced sodium oxide precursors have the same performance as products produced from existing metal salt raw materials, and the cost is greatly reduced.

[0070] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate, characterized in that: The chemical formula of sodium oxide is Ni 1-x-y-z Fe x Mn y Cu z O2, where 0<x<1, 0<y<1, 0<z<1, 0<x+y+z<1; The method comprises the following steps: S1: Immerse the copper-manganese slag produced by nickel smelting in a high-purity leaching tank with acid to obtain a leachate containing Cu and Mn; S2: The leaching solution is supplemented with Cu, Mn, Ni, and Fe elements according to the molar percentage of the elements required for the sodium electrode material to prepare the metal solution required for the sodium electrode; the raw materials used in the supplementation include nitrate, sulfate, or chloride, or a combination of several thereof; S3: The replenished leachate is atomized by a carrier gas and sent into a spray pyrolysis furnace, where it is evaporated, dried, and pyrolyzed at high temperature to obtain a sodium oxide precursor; S4: The tail gas discharged from the spray pyrolysis furnace is absorbed and purified by an absorption tower to form recovered acid. When the concentration of the recovered acid reaches the standard, the recovered acid is returned to the high-purity leaching tank in S1 for reuse; the waste heat in the tail gas is absorbed by a heat exchanger and used to heat the leachate before entering the spray pyrolysis furnace; In S4, the concentration of the recovered acid is tested every 24 hours. When the concentration reaches 80-120 g / L, the recovered acid is returned to the high-purity leaching tank for reuse, and the absorption tower is replenished with tail gas absorption liquid. If the concentration is lower than 80-120 g / L, the recovered acid is concentrated or blended with a high-concentration acid of the same type. If the concentration is higher than 80-120 g / L, deionized water or distilled water is added for dilution.

2. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S1, the acid is sulfuric acid, hydrochloric acid or nitric acid, with a concentration of 80-120 g / L and a temperature of 70-80°C.

3. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S1, the solid-liquid ratio of the copper-manganese slag to the acid is 1:(3-6), and the immersion time in the acid solution is 5-10 hours.

4. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S2, the ion concentration of the leaching solution after replenishment is 1-5 mol / L, which is the sum of the concentrations of four metal ions of Ni, Fe, Mn, and Cu; and the temperature of the leaching solution is 30-50°C.

5. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S3, the carrier gas is compressed air, nitrogen or oxygen, and the carrier gas flow rate is 20-40m³ / H.

6. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S3, the evaporation temperature is 300-400°C, the drying temperature is 500-600°C, and the pyrolysis temperature is 700-900°C.

7. The method for producing a sodium oxide precursor by direct spray pyrolysis of a copper-manganese slag leachate according to claim 1, characterized in that: In S1, the acid is nitric acid; in S2, the raw material used for re-mixing is nitrate.

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