A process for reducing lead content in lead anode mud

Abstract

The present invention develops a process for reducing the lead content in lead anode mud. The lead content in the lead anode mud can be reduced to less than 10% by subjecting the lead anode mud to a process of primary filter pressing-slurrying-secondary filter pressing. The filtered lead-containing filtrate is returned to the electrolyte system, which effectively improves the direct lead recovery rate and is beneficial to the subsequent recovery of other precious metals in the lead anode mud. At the same time, silicic acid is returned to the electrolyte system along with the lead-containing filtrate, which reduces the unit consumption of silicic acid. Moreover, the treated lead anode mud will not produce the phenomenon of spontaneous combustion and smoking.

Description

Technical Field

[0001] The invention relates to the technical field of pyrometallurgical lead smelting and electrolytic refining of crude lead, in particular to a process for reducing the lead content of lead anode mud. Background Art

[0002] Lead anode mud is a by-product of the lead electrolytic refining process and an important secondary resource. It includes precious metals such as gold and silver, as well as higher-grade lead.

[0003] During the process of electrolytic refining of crude lead with silicofluoric acid, lead anode mud is produced at the anode, and the lead content reaches 15%-20%. The distribution of lead components is as follows:

[0004] Lead-containing components Lead fluorosilicate Lead oxide Lead fluoride Lead silicate Lead sulfide Lead sulfate Lead Other lead phases Anode mud content ～1.0％ ～0.9％ ～3.3％ ～8.0％ ～1.4％ ～1.1％ ～0.6％ ～0.7％ Total lead percentage ～6.0％ ～5.5％ ～20.0％ ～46.0％ ～8.0％ ～7.0％ ～3.0％ ～4.5％

[0005] When the lead content of lead anode mud is high, it directly reduces the lead recovery rate; and the high lead content causes great trouble to the subsequent recovery of other precious metals in the lead anode mud, so reducing the lead content of the anode mud is an important indicator of the level of lead electrolytic refining. In addition, the content of silicic acid in the lead anode mud is high. If it is not recovered, the unit consumption of silicic acid will be greatly increased; and because the untreated lead anode mud will produce spontaneous combustion and smoke, it will form a safety hazard and worsen the working environment.

[0006] In the prior art, the conventional anode mud treatment method does not include a membrane filter press or only includes a membrane filter press once, resulting in a high lead content in the anode mud, reaching more than 10%. Summary of the invention

[0007] The present invention develops a process for reducing the lead content in lead anode mud. The lead content in the lead anode mud can be reduced to less than 10% by subjecting the lead anode mud to a process of primary filter pressing-slurrying-secondary filter pressing. The filtered lead-containing filtrate is returned to the electrolyte system, which effectively improves the direct lead recovery rate and is beneficial to the subsequent recovery of other precious metals in the lead anode mud. At the same time, silicic acid is returned to the electrolyte system along with the lead-containing filtrate, which reduces the unit consumption of silicic acid. Moreover, the treated lead anode mud will not produce the phenomenon of spontaneous combustion and smoking.

[0008] A process for reducing the lead content of lead anode mud, the process comprising the following steps:

[0009] S10. Primary filtration:

[0010] The lead anode mud is sent to a primary filter press for filtration, and then squeezed by a primary squeezing water pump to obtain primary anode mud;

[0011] S20. Pulping

[0012] Add clean water into the slurry tank, and the primary anode mud enters the slurry tank and is slurried for 5-10 minutes to obtain the slurried anode mud;

[0013] S30. Secondary filtration

[0014] The slurried anode mud is sent to the secondary filter press for filtration, and is squeezed by the secondary squeezing water pump to obtain dry anode mud.

[0015] Furthermore, the S10 primary filter pressing process is as follows:

[0016] S101. The lead anode mud is sent to a primary filter press for filtration until the primary filter press is full, and the filtration is stopped;

[0017] S102. After the filtration is completed, the filter press is automatically opened after a water pressing pump is used to obtain anode mud.

[0018] Furthermore, the S20 pulping process is as follows:

[0019] S201. Add water into the slurry tank;

[0020] S202. Blowing compressed air into the slurry tank liquid;

[0021] S203. The primary anode mud is unloaded into a slurrying tank and slurried for 5-10 minutes to obtain slurried anode mud.

[0022] Furthermore, in the S20 slurrying process, the mass ratio of clean water to primary anode mud is 1-2:1.

[0023] Furthermore, in the S20 slurrying process, the pressure of the compressed air is ≥0.4MPa.

[0024] Furthermore, the S30 secondary filter pressing process is as follows:

[0025] S301. The anode slurry after slurrying is sent to the secondary filter press for filtration until the secondary filter press is full and the filtration is stopped;

[0026] S302. After the filtration is completed, the secondary filter press is automatically opened by the secondary pressing water pump to obtain dry anode mud.

[0027] Furthermore, in the S20 slurrying process, the gelatin hydrolyzed solution is used instead of water, and the preparation process of the gelatin hydrolyzed solution is as follows:

[0028] (1) taking a certain amount of bone glue and placing it in a hydrolysis reactor, then adding 10% acetic acid with a mass fraction of 3-5 times the mass of bone glue, heating to 110°C-120°C, and reacting for 5h-8h;

[0029] (2) taking the supernatant, then adding 8-10 times the volume of clean water to dilute it, and finally adding perchloric acid to make the mass fraction of perchloric acid in the aqueous solution be 0.5‰-1.0‰, to prepare a gelatin hydrolysis solution.

[0030] Advantages of the present invention:

[0031] 1. The present invention reduces the lead content in the lead anode mud to less than 10% by subjecting the lead anode mud to a process of primary filter pressing-slurrying-secondary filter pressing. The filtered lead-containing filtrate is returned to the electrolyte system, which effectively improves the lead direct recovery rate and is conducive to the subsequent recovery of other precious metals in the lead anode mud. At the same time, silicic acid is returned to the electrolyte system along with the lead-containing filtrate, which reduces the unit consumption of silicic acid. Moreover, the treated lead anode mud will not produce the phenomenon of spontaneous combustion and smoking.

[0032] 2. The gelatin hydrolyzate solution helps to further reduce the lead content of lead anode mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0034] Example 1

[0035] A process for reducing the lead content of lead anode mud, the process comprising the following steps:

[0036] S10. Primary filtration:

[0037] S101. The lead anode mud is sent to a primary filter press for filtration until the primary filter press is full, and the filtration is stopped;

[0038] S102. After the filtration is completed, the filter press is automatically opened after a water pressing pump is used to obtain anode mud;

[0039] S20. Pulping

[0040] S201. Add clean water into the slurry tank, the mass ratio of clean water to primary anode mud is 1.5:1;

[0041] S202. Blow compressed air under the slurry tank liquid, the pressure of the compressed air is 0.4MPa;

[0042] S203. The primary anode mud is unloaded into a slurry tank and slurried for 7 minutes to obtain slurried anode mud;

[0043] S30. Secondary filtration

[0044] S301. The anode slurry after slurrying is sent to the secondary filter press for filtration until the secondary filter press is full and the filtration is stopped;

[0045] S302. After the filtration is completed, the secondary filter press is automatically opened by the secondary pressing water pump to obtain dry anode mud.

[0046] Example 2

[0047] A process for reducing the lead content of lead anode mud, wherein in the S20 slurrying process, gelatin hydrolysis solution is used to replace clean water, and the remaining processes are the same as those in Example 1.

[0048] The preparation process of the bone glue hydrolysis solution is as follows:

[0049] (1) A certain amount of bone gelatin is placed in a hydrolysis reactor, and then 10% acetic acid (4 times the mass of bone gelatin) is added, heated to 115°C, and reacted for 6 hours;

[0050] (2) taking the supernatant, adding 9 times the volume of clean water to dilute it, and finally adding perchloric acid so that the mass fraction of perchloric acid in the aqueous solution is 0.8‰, thereby preparing a gelatin hydrolysis solution.

[0051] Comparative Example 1

[0052] The primary anode mud obtained by the S10 primary filter press process in Example 1 was used as a comparison.

[0053] Comparative Example 2

[0054] An equal amount of unhydrolyzed gelatin aqueous solution with the same solid content as the gelatin hydrolysis solution was used to replace the clean water in the S20 slurrying process, and the rest was the same as in Example 1.

[0055] Comparative Example 3

[0056] In the S20 slurrying process, 0.8‰ perchloric acid is added to the clean water, and the rest is the same as in Example 1.

[0057] Comparative Example 4

[0058] No perchloric acid was added to the gelatin hydrolysis solution, and the rest was the same as in Example 2.

[0059] Test: The same batch of lead anode mud (lead content of 19.3%) was treated according to the above-mentioned embodiment and comparative example processes, and the lead content of the treated dry anode mud was finally detected.

[0060] Dry anode mud Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Lead content (%) 8.6 4.2 13.4 8.8 7.4 5.6

[0061] Among them, in Comparative Example 2, since the gelatin was not hydrolyzed, the viscosity of the anode mud after slurrying was relatively high, the resistance during the secondary filter pressing was large, and the filter pressing was extremely time-consuming.

[0062] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for reducing the lead content of lead anode mud, characterized by: The process comprises the following steps: S10. Primary filtration: The lead anode mud is sent to the primary filter press for filtration, and then squeezed by the primary water pump to obtain the primary anode mud; S20. Pulping Adding bone gelatin hydrolysis solution into the slurrying tank, the primary anode mud enters the slurrying tank, the mass ratio of bone gelatin hydrolysis solution to primary anode mud is 1-2:1, slurrying for 5-10 minutes, and obtaining slurried anode mud; The preparation process of the bone glue hydrolysis solution is as follows: (1) Place a certain amount of bone gelatin in a hydrolysis reactor, then add 10% acetic acid (3-5 times the mass of the bone gelatin), heat to 110-120°C, and react for 5-8 hours; (2) taking the supernatant, then adding 8-10 times the volume of water to dilute it, and finally adding perchloric acid to make the mass fraction of perchloric acid in the aqueous solution be 0.5‰-1.0‰, to prepare a gelatin hydrolysis solution; S30. Secondary filtration The slurried anode mud is sent to the secondary filter press for filtration, and is squeezed by the secondary squeezing water pump to obtain dry anode mud.

2. The process for reducing the lead content of lead anode slime according to claim 1, characterized in that: The S10 primary filter press process is as follows: S101. The lead anode mud is sent to a primary filter press for filtration until the primary filter press is full and the filtration is stopped; S102. After the filtration is completed, the filter press is automatically opened after a water pressing pump is used to obtain anode mud.

3. The process for reducing the lead content of lead anode slime according to claim 1, characterized in that: The S20 slurrying process is as follows: S201. Adding gelatin hydrolysis solution into the pulping tank; S202. Blowing compressed air into the slurry tank liquid; S203. Unload the primary anode mud into a slurrying tank and slurry for 5-10 minutes to obtain slurried anode mud.

4. The process for reducing the lead content of lead anode slime according to claim 3, characterized in that: In the S20 slurrying process, the pressure of the compressed air is ≥0.4MPa.

5. The process for reducing the lead content of lead anode slime according to claim 1, characterized in that: The S30 secondary filter press process is as follows: S301. The anode slurry is then slurried into a secondary filter press until the secondary filter press is full and the filter press is stopped; S302. After the filtration is completed, the secondary pressing water pump is used to press the secondary filter press, and the plates are automatically opened to obtain dry anode mud.

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