A method for high-efficiency extraction of lead and zinc from lead-zinc oxide ore at normal temperature and pressure

Abstract

This invention discloses a method for efficient extraction of lead and zinc from oxidized lead-zinc ore at room temperature and pressure, belonging to the field of non-ferrous metal hydrometallurgical technology. The invention includes (1) adding a mixed solution of ammonium chloride and citric acid as a leaching agent to the oxidized lead-zinc ore and conducting a stirring reaction at room temperature and pressure; (2) after the reaction is completed, performing solid-liquid separation to simultaneously leach lead and zinc. By using a mixed solution of citric acid and NH4Cl as a leaching agent, this invention can effectively achieve efficient leaching of valuable metals such as lead and zinc from oxidized lead-zinc ore under mild conditions, while simultaneously inhibiting the dissolution of impurities (such as iron and silicon). This avoids the high energy consumption of traditional high-temperature and high-pressure methods and the problem of silica gel formation that easily affects solid-liquid separation in traditional acid leaching. It achieves efficient extraction of oxidized lead-zinc ore resources under normal pressure and temperature conditions, providing a scientifically reliable new approach for the resource utilization of oxidized lead-zinc ore.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal hydrometallurgical technology and relates to a method for efficiently extracting lead and zinc from oxidized lead-zinc ore at room temperature and pressure. Background Technology

[0002] Lead and zinc, as important non-ferrous metals, are widely used in battery manufacturing, chemical industry, casting and other fields. Currently, lead-zinc ore resources are generally characterized by "large total amount, low grade, concentrated distribution and complex associated minerals". With the continuous growth in demand for lead and zinc resources, how to efficiently recover and utilize lead and zinc resources in oxide lead-zinc ores is of great significance.

[0003] Currently, the metallurgical processes for oxide lead-zinc ores are mainly divided into two categories: pyrometallurgy and hydrometallurgy. Pyrometallurgy, based on the low melting and boiling points of lead and zinc, relies on high-temperature conditions and utilizes reduction-oxidation reactions to separate and extract lead and zinc resources. However, pyrometallurgical processes require high temperatures and produce polluting gases such as sulfur dioxide and carbon dioxide, resulting in high energy consumption, significant emissions, and substantial environmental pressure. In contrast, hydrometallurgical processes are relatively simple to operate and consume less energy, thus attracting wider attention.

[0004] However, existing wet leaching processes still have significant shortcomings: alkaline leaching often uses high-concentration sodium hydroxide solution as the leaching agent, which is highly corrosive and easily damages equipment. Furthermore, the introduction of sodium can interfere with subsequent electrolysis processes, increasing the difficulty of wastewater treatment. Ammonia leaching is relatively sensitive to zinc minerals such as zirconia and smithsonite. If zinc in the ore exists in the form of zirconia or smithsonite, it is easily leached. However, when zinc in the ore exists in the form of silicates, even under relatively harsh environmental conditions (such as high temperature and high pressure), the leaching effect is still poor. Ammonia also has disadvantages such as high volatility and weak coordination ability with lead, resulting in a significant environmental pollution risk and greatly limiting its practical application. Acid leaching typically uses sulfuric acid as the leaching agent, which easily leads to silica gel formation, affecting subsequent solid-liquid separation. Moreover, the acidity and strong oxidizing properties of sulfuric acid cause a large amount of impurities such as iron, calcium, magnesium, aluminum, and silicon to dissolve during acid leaching, increasing the difficulty of subsequent lead and zinc resource separation and purification.

[0005] Therefore, it is necessary to provide a method for efficiently extracting lead and zinc from oxidized lead-zinc ore at room temperature and pressure, which can effectively reduce energy consumption during the leaching process of lead and zinc resources, reduce the dissolution of iron and silicon, and achieve efficient recovery of lead and zinc simultaneously. Summary of the Invention

[0006] To overcome the problems in the prior art, the present invention uses a mixture of citric acid and ammonium chloride as a leaching agent to leverage the synergistic promoting effect of citric acid and ammonium chloride, thereby achieving highly selective leaching of lead and zinc resources.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] This invention proposes a method for efficient extraction of lead and zinc from oxidized lead-zinc ore at room temperature and pressure. A mixed solution of citric acid and ammonium chloride is used as the leaching agent to simultaneously leach lead and zinc from the oxidized lead-zinc ore under room temperature and pressure conditions. The method includes the following steps:

[0009] (1) Add a mixed solution of ammonium chloride and citric acid as a leaching agent to the lead-zinc oxide ore and carry out a stirring reaction at room temperature and pressure;

[0010] (2) After the reaction is completed, solid-liquid separation is carried out to leach lead and zinc simultaneously.

[0011] Solid-liquid separation can be carried out using conventional methods such as filtration and centrifugation.

[0012] Preferably, in step (1), the liquid-to-solid ratio of the leaching agent to the oxidized lead-zinc ore is 5~20 ml / g.

[0013] Preferably, the leaching agent contains citric acid at a concentration of 0.5-2 mol / L and ammonium chloride at a concentration of 3-7 mol / L.

[0014] Preferably, in step (1), the reaction time is 30~180 min.

[0015] Preferably, in step (1), the stirring speed is 300~2000 rpm.

[0016] Preferably, in step (1), the particle size of the lead-zinc oxide ore is <500μm.

[0017] If the lead-zinc oxide ore itself has a large particle size, the particle size can be controlled to below 500 μm before leaching by conventional means such as crushing.

[0018] Preferably, the lead-zinc oxide ore has a lead-zinc grade greater than 1%.

[0019] Preferably, in the oxidized lead-zinc ore, the zinc mineral includes at least one of zinc oxide, smithsonite, zinc siliceous ore, hemimorphite, and hydrozinc ore.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention uses a mixed solution of citric acid and ammonium chloride as a leaching agent. Through the synergistic effect of the two, a chemical inertness is formed against impurities such as iron and silicon, effectively avoiding the formation of silica gel while achieving efficient and selective leaching of lead and zinc.

[0022] 2. This invention can achieve efficient and selective leaching of lead and zinc resources under normal temperature and pressure conditions, effectively reducing energy consumption and equipment investment, and helping to reduce the overall cost of hydrometallurgical processing of oxidized lead and zinc ores.

[0023] 3. The present invention operates under mild conditions and is simple to operate, enabling simultaneous and highly selective recovery of lead and zinc resources in oxidized lead-zinc ores. Compared with the limitations imposed by mineral grade, type, and required process conditions in traditional hydrometallurgical processes, it has certain guiding significance for the extraction of lead and zinc from oxidized lead-zinc ores and is suitable for industrial promotion and application. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0025] Figure 2 The XRD pattern of the lead-zinc oxide ore in this invention;

[0026] Figure 3 The XRD pattern of the leaching residue in Example 1 of this invention;

[0027] Figure 4 The XRD pattern of the leaching residue in Comparative Example 1 of this invention;

[0028] Figure 5 The image shows the XRD pattern of the leaching residue in Comparative Example 2 of this invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0030] The composition of lead-zinc oxide ore in the embodiments and comparative examples of this invention is shown in Table 1, and the phases are as follows: Figure 2 As shown.

[0031] Table 1

[0032]

[0033] Example 1

[0034] This embodiment describes the extraction and recovery of lead and zinc resources from oxidized lead-zinc ore using the following method:

[0035] (1) Weigh out lead-zinc oxide ore and add it to the reaction vessel. Then, add a mixed solution of ammonium chloride (NH4Cl) and citric acid to the reaction vessel. The liquid-solid ratio of the mixed solution to the lead-zinc oxide ore is 7 ml / g. The concentration of NH4Cl in the mixed solution is 5 mol / L, and the concentration of citric acid is 1 mol / L. Stir the reaction system at 400 rpm and react for 90 min at room temperature and pressure.

[0036] (2) After leaching, solid-liquid separation is carried out to obtain a leachate containing lead and zinc and a leaching residue.

[0037] The leachate was tested using the formula. The leaching rates of lead, zinc, iron, and silicon were calculated using the formula (where x is the leaching rate; C is the concentration of one of the lead, zinc, iron, and silicon ions in the leachate, in g / L; V is the total volume of the leachate, in L; W is the mass percentage of lead, zinc, iron, and silicon in the oxidized lead-zinc ore; and Ms is the mass of the oxidized lead-zinc ore specifically weighed in the example, in g). The results are as follows:

[0038] The zinc leaching rate was 96.05%, the lead leaching rate was 97.82%, the iron leaching rate was 0.3%, and the silicon leaching rate was 2.13%.

[0039] Example 2

[0040] This embodiment describes the extraction and recovery of lead and zinc resources from oxidized lead-zinc ore using the following method:

[0041] (1) Weigh out lead-zinc oxide ore and add it to the reaction vessel. Then, add a mixed solution of ammonium chloride (NH4Cl) and citric acid to the reaction vessel. The liquid-solid ratio of the mixed solution to the lead-zinc oxide ore is 20 ml / g. The concentration of NH4Cl in the mixed solution is 3 mol / L, and the concentration of citric acid is 2 mol / L. Stir the reaction system at 2000 rpm and react for 180 min at room temperature and pressure.

[0042] (2) After leaching, solid-liquid separation is carried out to obtain a leachate containing lead and zinc and a leaching residue.

[0043] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0044] The zinc leaching rate was 94.96%, and the lead leaching rate was 88.68%.

[0045] Example 3

[0046] This embodiment describes the extraction and recovery of lead and zinc resources from oxidized lead-zinc ore using the following method:

[0047] (1) Weigh out lead-zinc oxide ore and add it to the reaction vessel. Then, add a mixed solution of ammonium chloride (NH4Cl) and citric acid to the reaction vessel. The liquid-solid ratio of the mixed solution to the lead-zinc oxide ore is 5 ml / g. The concentration of NH4Cl in the mixed solution is 7 mol / L, and the concentration of citric acid is 0.5 mol / L. Stir the reaction system at 400 rpm and react for 120 min at room temperature and pressure.

[0048] (2) After leaching, solid-liquid separation is carried out to obtain a leachate containing lead and zinc and a leaching residue.

[0049] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0050] The leaching rate of zinc was 86.92%, and the leaching rate of lead was 87.42%.

[0051] Example 4

[0052] This embodiment describes the extraction and recovery of lead and zinc resources from oxidized lead-zinc ore using the following method:

[0053] (1) Weigh out lead-zinc oxide ore and add it to the reaction vessel. Then, add a mixed solution of ammonium chloride (NH4Cl) and citric acid to the reaction vessel. The liquid-solid ratio of the mixed solution to the lead-zinc oxide ore is 8 ml / g. The concentration of NH4Cl in the mixed solution is 7 mol / L, and the concentration of citric acid is 1 mol / L. Stir the reaction system at 400 rpm and react for 30 min at room temperature and pressure.

[0054] (2) After leaching, solid-liquid separation is carried out to obtain a leachate containing lead and zinc and a leaching residue.

[0055] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0056] The zinc leaching rate was 83.29%, and the lead leaching rate was 85.03%.

[0057] Example 5

[0058] This embodiment describes the extraction and recovery of lead and zinc resources from oxidized lead-zinc ore using the following method:

[0059] (1) Weigh out lead-zinc oxide ore and add it to the reaction vessel. Then, add a mixed solution of ammonium chloride (NH4Cl) and citric acid to the reaction vessel. The liquid-solid ratio of the mixed solution to the lead-zinc oxide ore is 7 ml / g. The concentration of NH4Cl in the mixed solution is 5 mol / L, and the concentration of citric acid is 1 mol / L. Stir the reaction system at 300 rpm and react for 90 min at room temperature and pressure.

[0060] (2) After leaching, solid-liquid separation is carried out to obtain a leachate containing lead and zinc and a leaching residue.

[0061] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0062] The zinc leaching rate was 92.32%, and the lead leaching rate was 91.95%.

[0063] Comparative Example 1

[0064] This comparative example uses the same method as Example 1 to leach lead and zinc resources in oxidized lead-zinc ore, the difference being that this comparative example only uses NH4Cl solution as the leaching agent, and the concentration of NH4Cl in the solution is 5 mol / L.

[0065] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0066] The zinc leaching rate was 4.1%, and the lead leaching rate was 0%.

[0067] Comparative Example 2

[0068] This comparative example uses the same method as Example 1 to leach lead and zinc resources in oxidized lead-zinc ore, the difference being that this comparative example only uses citric acid solution as the leaching agent, and the concentration of citric acid in the solution is 1 mol / L.

[0069] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0070] The zinc leaching rate was 85.63%, and the lead leaching rate was 13.62%.

[0071] Comparative Example 3

[0072] This comparative example uses the same method as Example 1 to leach lead and zinc resources in oxidized lead-zinc ore, the difference being that: this comparative example uses a mixed solution of H2SO4 and NH4Cl as the leaching agent, in which the concentration of H2SO4 is 1 mol / L and the concentration of NH4Cl is 5 mol / L.

[0073] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0074] The zinc leaching rate was 85.95%, and the lead leaching rate was 71.56%.

[0075] Comparative Example 4

[0076] This comparative example uses the same method as Example 1 to leach lead and zinc resources in oxidized lead-zinc ore. The difference is that this comparative example uses a mixed solution of citric acid and ammonia as the leaching agent. The concentration of citric acid in the solution is 1 mol / L and the concentration of ammonia is 5 mol / L.

[0077] The leachate was tested, and the leaching rates of lead and zinc were calculated. The results are as follows:

[0078] The zinc leaching rate was 17.59%, and the lead leaching rate was 0%.

[0079] A comparison of Example 1 with Comparative Examples 1-4 shows that NH4Cl alone has almost no leaching effect on lead and zinc resources, while citric acid alone has almost no leaching effect on lead resources. After replacing citric acid or NH4Cl with similar substances, the leaching rates of lead and zinc decreased significantly. This fully demonstrates that the synergistic effect between citric acid and NH4Cl can effectively improve the leaching rate of lead and zinc under normal temperature and pressure conditions, achieving high selective leaching of lead and zinc resources simultaneously, thereby improving the recycling rate of lead and zinc resources and alleviating resource waste.

[0080] contrast Figure 2 , 3 As can be seen from points 4 and 5, the mixed system of citric acid and NH4Cl has better solubility for zinc silicate compared to other systems (NH4Cl alone and citric acid alone), enabling efficient leaching of zinc under normal temperature and pressure conditions.

[0081] In summary, by using a mixed solution of citric acid and NH4Cl as a leaching agent, this invention fully leverages the synergistic effect of citric acid and NH4Cl to achieve highly selective simultaneous leaching of lead and zinc under mild conditions. Furthermore, it inhibits easily leached impurities such as iron and silicon, reducing the impurity content in the leached lead and zinc, thus laying a solid foundation for the purification of high-purity lead and zinc resources.

[0082] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for efficient extraction of lead and zinc from oxidized lead-zinc ore at room temperature and pressure, characterized in that: A method for simultaneously leaching lead and zinc from oxidized lead-zinc ore using a mixed solution of citric acid and ammonium chloride as the leaching agent under ambient temperature and pressure conditions includes the following steps: (1) Add a mixed solution of ammonium chloride and citric acid as a leaching agent to the lead-zinc oxide ore and carry out a stirring reaction at room temperature and pressure; (2) After the reaction is complete, solid-liquid separation is carried out to simultaneously leach lead and zinc; The zinc mineral in the oxidized lead-zinc ore includes at least one of zinc oxide, smithsonite, zinc siliceous ore, hemimorphite, and hydrozinc ore.

2. The method according to claim 1, characterized in that: In step (1), the liquid-solid ratio of the leaching agent to the oxidized lead-zinc ore is 5~20 ml / g.

3. The method according to claim 1, characterized in that: The leaching agent contains citric acid at a concentration of 0.5-2 mol / L and ammonium chloride at a concentration of 3-7 mol / L.

4. The method according to claim 1, characterized in that: In step (1), the reaction time is 30~180 min.

5. The method according to claim 1, characterized in that: In step (1), the stirring speed is 300~2000 rpm.

6. The method according to claim 1, characterized in that: In step (1), the particle size of the oxidized lead-zinc ore is <500μm.

7. The method according to claim 1, characterized in that: In the aforementioned lead-zinc oxide ore, the lead and zinc grades are greater than 1%.

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