Tellurium recovery process based on lead anode slime

Abstract

The invention provides a tellurium recovery process based on lead anode slime, and belongs to the field of resource reutilization. The tellurium recovery process based on the lead anode slime comprises the following steps that the lead anode slime serves as a raw material, sodium carbonate and pulverized coal are added, the mass ratio of the lead anode slime to the sodium carbonate to the pulverized coal is 100: (8-9): (6-7), oxidation refining is carried out, and the oxidation refining temperature is 500-600 DEG C; the mass ratio of the added sodium hydroxide to the lead anode slime is (3-7): 100, the furnace temperature range of the tellurium slag is controlled to be 600-1000 DEG C, and the reaction time is 2-4 hours. Compared with a traditional process for recycling tellurium from tellurium making slag during silver blowing, the method has the advantages that due to the fact that tellurium is recycled in advance, the recycling rate and the direct recycling rate of tellurium in the system are increased, dispersion loss of tellurium in the bismuth recycling system is reduced (especially copper and tellurium are mixed together and difficult to separate during traditional copper removal of crude bismuth), and the production cost of tellurium is reduced. On the premise that tellurium and bismuth are greatly different in price, tellurium is recycled in advance, and enterprise fund turnover is facilitated.

Description

Technical Field

[0001] The invention relates to the field of resource recycling, and in particular to a tellurium recovery process based on lead anode mud. Background Art

[0002] Lead anode mud (LAS) is a harmful byproduct produced during lead electrolysis, containing a variety of metals and toxic components, posing a threat to environmental safety. It is of great significance to effectively separate and purify elements from lead anode mud.

[0003] The order of metal separation and recovery during the lead anode mud smelting process is antimony, bismuth, tellurium, and silver. The traditional tellurium recovery process is to separate tellurium by making tellurium slag during silver blowing. This process cannot effectively recover the tellurium lost in the bismuth separation section, resulting in a low tellurium recovery rate in the system. Repeated extraction is required, resulting in high costs and affecting the competitiveness of enterprises. Therefore, a new tellurium recovery process is urgently needed to solve the above problems. Summary of the invention

[0004] In view of this, the present invention proposes a tellurium recovery process based on lead anode mud, which has significant advantages in improving efficiency, reducing costs and protecting the environment.

[0005] The technical solution of the present invention is achieved in this way:

[0006] A tellurium recovery process based on lead anode mud comprises the following steps: using lead anode mud as raw material, adding sodium carbonate and pulverized coal for oxidation refining; then adding sodium hydroxide for oxidation to produce tellurium slag, wherein the furnace temperature of the oxidation to produce tellurium slag is controlled in the range of 600-1000°C, and the reaction time is 2-4 hours.

[0007] A large number of studies have found that when the temperature is lower than 600°C, a large amount of bismuth metal will enter the slag, reducing the tellurium content of the tellurium slag. When the temperature is higher than 1000°C, the amount of tellurium entering the slag will decrease, reducing the tellurium content of the tellurium slag. In addition, the reaction time of the oxidation to make tellurium slag in the present invention must be controlled. When the reaction time is short, the reaction is not complete and the amount of tellurium slag separation is small. When the reaction time is long, bismuth metal will enter the tellurium slag, reducing the recovery rate of bismuth.

[0008] A further technical solution is that the mass ratio of lead anode mud, sodium carbonate and pulverized coal is 100:8-9:6-7, preferably 100:8:6.

[0009] A further technical solution is to add sodium hydroxide and lead anode mud in a mass ratio of 3 to 7:100, preferably 5:100.

[0010] A further technical solution is that the temperature of the oxidation refining is 500-600°C.

[0011] A further technical solution is that the oxidation refining time is 70 to 75 hours.

[0012] A further technical solution is a tellurium recovery process based on lead anode mud, comprising the following steps:

[0013] (1) Lead anode mud is used as raw material, sodium carbonate and pulverized coal are added, and then the raw material is sent to a converter for reduction smelting. The mass ratio of lead anode mud, sodium carbonate and pulverized coal is 100:8-9:6-7; the produced thin slag is poured out to feed the lead system ingredients, and the molten metal in the furnace is poured into a steel mold and cooled, and then released and added to the antimony converter. The temperature is controlled at 500-600°C, and compressed air is introduced for oxidation refining for 70-75 hours;

[0014] (2) When the antimony content of the metal solution in the furnace is 3-5%, stop ventilation, control the furnace temperature range to 600-1000°C, introduce compressed air, add sodium hydroxide for oxidation to form tellurium slag, the mass ratio of sodium hydroxide to lead anode mud is 3-7:100, the reaction time is 2-4 hours, and the converter is discharged.

[0015] A further technical solution is that the compressed air has a pressure of 0.3-0.5 MPa and a flow rate of 100-200 m 3 / h.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) Compared with the conventional process of recovering tellurium by making tellurium slag during silver blowing, the present invention recovers tellurium in advance, thereby not only improving the recovery rate and direct recovery rate of tellurium in the system, but also reducing the dispersion loss of tellurium in the bismuth recovery system (especially the conventional process of removing copper from crude bismuth, which causes copper and tellurium to be mixed together and difficult to separate), and reducing the production cost of tellurium. Under the premise of the large price difference between tellurium and bismuth, recovering tellurium in advance is beneficial to the turnover of enterprise funds.

[0018] (2) The present invention controls the reaction temperature and reaction time of oxidation to tellurium slag, effectively improves the tellurium content of the tellurium slag, increases the separation amount of the tellurium slag, and effectively reduces the entry of bismuth metal into the tellurium slag, thereby improving the recovery rate of bismuth.

[0019] (3) The process of the present invention can effectively improve the recovery rate of tellurium, reduce production costs, improve resource utilization efficiency, and be more environmentally friendly. DETAILED DESCRIPTION

[0020] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0021] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0022] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0023] Soda ash: sodium carbonate.

[0024] Caustic soda flakes: sodium hydroxide.

[0025] The main components of the lead anode mud used in the embodiment of the present invention are:

[0026] Table 1 Main components of lead anode mud

[0027] Lead anode mud composition Te Bi Sb Pb Mass percentage 0.5％ 30％ 25％ 10％

[0028] The present invention is based on the tellurium recovery process of lead anode mud, comprising the following steps:

[0029] (1) Lead anode mud is added with soda ash (sodium carbonate) and pulverized coal and then sent to the converter for reduction smelting. The mass ratio of lead anode mud, soda ash and pulverized coal is 100:8-9:6-7; the produced thin slag is poured out and sent to the lead system for batching. The molten metal in the furnace is poured into a steel mold and cooled, then released and added to the antimony converter. The temperature is controlled at 500-600°C, and compressed air is introduced for oxidation refining for 70-75 hours, so that antimony, arsenic and a small amount of lead and bismuth are volatilized into smoke. The antimony oxide powder is collected by the dust collection system and sold as a product.

[0030] (2) When the antimony content of the metal solution in the furnace is 3-5% when sampled and tested, ventilation is stopped, the furnace temperature is controlled to be in the range of 600-1000°C, compressed air is introduced, and caustic soda flakes are added for oxidation to make tellurium slag. The amount of caustic soda flakes added is 15-40 bags, and the mass ratio of caustic soda flakes to lead anode mud is 3-7:100. After the reaction time is 2-4 hours, the converter is discharged and the solution is taken for test of tellurium. If the tellurium content is greater than 1%, the above-mentioned tellurium slag making process is repeated until the tellurium content of the metal solution (crude bismuth) in the furnace is less than 1%.

[0031] The above compressed air pressure is 0.3-0.5MPa, and the flow rate is 100-200m 3 / h.

[0032] The tellurium slag composition was analyzed, and the comprehensive recovery rate and direct recovery rate of tellurium were calculated. The formula is as follows:

[0033] Direct recovery rate = (tellurium slag weight × tellurium grade in tellurium slag) / (lead anode mud weight × tellurium grade in lead anode mud) × 100%

[0034] Comprehensive recovery rate = (tellurium slag weight × tellurium grade of tellurium slag + dilute slag weight × tellurium grade of dilute slag + smoke weight × tellurium grade of dilute slag) / (lead anode mud weight × tellurium grade in lead anode mud) × 100%

[0035] Among them, the metals in the thin slag and smoke can be recovered through the system.

[0036] Example 1

[0037] A tellurium recovery process based on lead anode mud comprises the following steps:

[0038] (1) The lead anode mud is added with soda ash (sodium carbonate) and pulverized coal and then sent to the converter for reduction smelting. The mass ratio of lead anode mud, soda ash and pulverized coal is 100:8:6; the produced thin slag is poured out to the lead system for batching. The molten metal in the furnace is poured into a steel mold and cooled before being released and added to the antimony converter. The temperature is controlled at 550℃±50℃, and compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h) for oxidative refining for 72 hours, so that antimony, arsenic and a small amount of lead and bismuth are volatilized into smoke, and antimony oxide powder is collected by a dust collection system and sold as a product.

[0039] (2) When the antimony content of the metal solution in the furnace is 3-5% when sampled and tested, stop ventilation, control the furnace temperature range to 700℃±50℃, and introduce compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h), adding caustic soda flakes for oxidation to make tellurium slag, the mass ratio of caustic soda flakes to lead anode mud is 5:100, the converter is discharged after 3 hours of reaction time, and the solution is taken for tellurium testing. If the tellurium content is greater than 1%, the above-mentioned tellurium slag making process is repeated until the tellurium content of the metal solution (crude bismuth) in the furnace is less than 1%.

[0040] Results: As shown in Table 1, the tellurium slag produced by the present invention has the following components: Te 20%, Bi 8%, Sb 2.5%, Pb 2.6%, and the tellurium slag fully meets the process requirements of the next tellurium wet leaching process to recover tellurium ingots; and the tellurium content of the metal solution after slag making is less than 0.5%, which has very little impact on subsequent recovery and silver (the subsequent vacuum furnace entry requirement is Te < 0.5%).

[0041] Table 2 Tellurium slag composition

[0042] Tellurium slag ingredients Te Bi Sb Pb Mass percentage 20.0％ 8.0％ 2.5％ 2.6％

[0043] The comprehensive recovery rate of tellurium in this embodiment is 95.5%, and the direct recovery rate is 90.6%.

[0044] Example 2

[0045] A tellurium recovery process based on lead anode mud comprises the following steps:

[0046] (1) The lead anode mud is added with soda ash (sodium carbonate) and pulverized coal and then sent to the converter for reduction smelting. The mass ratio of lead anode mud, soda ash and pulverized coal is 100:8:6; the produced thin slag is poured out to the lead system for batching, and the molten metal in the furnace is poured into a steel mold and cooled before being released and added to the antimony converter. The temperature is controlled at 550℃±50℃, and compressed air (compressed air pressure 0.3MPa, flow rate 200m 3 / h) for oxidative refining for 72 hours, so that antimony, arsenic and a small amount of lead and bismuth are volatilized into smoke, and antimony oxide powder is collected by a dust collection system and sold as a product.

[0047] (2) When the antimony content of the metal solution in the furnace is 3-5%, stop ventilation, control the furnace temperature range to 800℃±50℃, and introduce compressed air (compressed air pressure 0.3MPa, flow rate 200m 3 / h), adding caustic soda flakes for oxidation to make tellurium slag, the mass ratio of caustic soda flakes to lead anode mud is 5:100, the converter is discharged after 4 hours of reaction time, and the solution is taken for tellurium testing. If the tellurium content is greater than 1%, the above-mentioned tellurium slag making process is repeated until the tellurium content of the metal solution (crude bismuth) in the furnace is less than 1%.

[0048] Table 3 Tellurium slag composition

[0049] Tellurium slag ingredients Te Bi Sb Pb Mass percentage 19.5％ 8.2％ 2.4％ 2.8％

[0050] The comprehensive recovery rate of tellurium in this embodiment is 96.0%, and the direct recovery rate is 91.0%.

[0051] Example 3

[0052] A tellurium recovery process based on lead anode mud comprises the following steps:

[0053] (1) The lead anode mud is mixed with soda ash (sodium carbonate) and pulverized coal and then sent to the converter for reduction smelting. The mass ratio of lead anode mud, soda ash and pulverized coal is 100:8:6; the produced thin slag is poured out to the lead system for batching, and the molten metal in the furnace is poured into a steel mold and cooled before being released and added to the antimony converter. The temperature is controlled at 550℃±50℃, and compressed air (compressed air pressure 0.5MPa, flow rate 100m 3 / h) for oxidative refining for 72 hours, so that antimony, arsenic and a small amount of lead and bismuth are volatilized into smoke, and antimony oxide powder is collected by a dust collection system and sold as a product.

[0054] (2) When the antimony content of the metal solution in the furnace is 3-5%, stop ventilation, control the furnace temperature range to 900℃±50℃, and introduce compressed air (compressed air pressure 0.5MPa, flow rate 100m 3 / h), adding caustic soda flakes for oxidation to make tellurium slag, the mass ratio of caustic soda flakes to lead anode mud is 5:100, the converter is discharged after 2 hours of reaction time, and the solution is taken for tellurium testing. If the tellurium content is greater than 1%, the above-mentioned tellurium slag making process is repeated until the tellurium content of the metal solution (crude bismuth) in the furnace is less than 1%.

[0055] Table 4 Tellurium slag composition

[0056] Tellurium slag ingredients Te Bi Sb Pb Mass percentage 19.1％ 8.3％ 2.6％ 2.7％

[0057] The comprehensive recovery rate of tellurium in this embodiment is 95.2%, and the direct recovery rate is 90.8%.

[0058] Comparative Example 1

[0059] On the basis of Example 1, the temperature of the furnace is controlled at 450℃±50℃ for oxidized tellurium slag. Specifically, when the antimony content of the metal solution in the furnace is 3-5% after sampling, the ventilation is stopped, the furnace temperature is controlled at 450℃±50℃, and compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h), adding caustic soda flakes for oxidation to produce tellurium slag, and the converter is slag-discharging after a reaction time of 3 hours. The other process steps are the same as those in Example 1.

[0060] The results showed that this temperature would cause a large amount of bismuth metal to enter the slag, reducing the tellurium content of the tellurium slag.

[0061] Comparative Example 2

[0062] On the basis of Example 1, the temperature of the furnace is controlled within the range of 1150°C ± 50°C for oxidized tellurium slag. Specifically, when the antimony content of the metal solution in the furnace is 3-5% after sampling, ventilation is stopped, the furnace temperature is controlled within the range of 1150°C ± 50°C, and compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h), adding caustic soda flakes for oxidation to produce tellurium slag, and the converter is slag-discharging after a reaction time of 3 hours. The other process steps are the same as those in Example 1.

[0063] The results show that this temperature will cause less tellurium to enter the slag, thereby reducing the tellurium content of the tellurium slag.

[0064] Comparative Example 3

[0065] On the basis of Example 1, the reaction time of oxidation to tellurium slag was adjusted to 1 hour. Specifically, when the antimony content of the metal solution in the furnace was 3-5% after sampling, the ventilation was stopped, the furnace temperature was controlled to 800℃±50℃, and compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h), adding caustic soda flakes for oxidation to produce tellurium slag, and the converter is slag-discharging after 1 hour of reaction. The other process steps are the same as those in Example 1.

[0066] It was found that this reaction time would result in an incomplete reaction and a small amount of tellurium slag separated.

[0067] Comparative Example 4

[0068] On the basis of Example 1, the reaction time of oxidation tellurium slag was adjusted to 5 hours. Specifically, when the antimony content of the metal solution in the furnace was 3-5% after sampling, the ventilation was stopped, the furnace temperature was controlled to 800℃±50℃, and compressed air (compressed air pressure 0.4MPa, flow rate 150m 3 / h), adding caustic soda flakes for oxidation to produce tellurium slag, and the converter is slag-discharging after 5 hours of reaction time. The other process steps are the same as those in Example 1.

[0069] The results showed that the reaction time would cause bismuth metal to enter the tellurium slag, reducing the recovery rate of bismuth.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A tellurium recovery process based on lead anode mud, characterized in that: The method comprises the following steps: using lead anode mud as raw material, adding sodium carbonate and pulverized coal for oxidation refining; then adding sodium hydroxide for oxidation to produce tellurium slag, wherein the furnace temperature of the oxidation to produce tellurium slag is controlled in the range of 600-1000°C and the reaction time is 2-4h.

2. The tellurium recovery process based on lead anode mud according to claim 1, characterized in that: The mass ratio of lead anode mud, sodium carbonate and pulverized coal is 100:8-9:6-7.

3. The tellurium recovery process based on lead anode mud according to claim 1, characterized in that: The mass ratio of added sodium hydroxide to lead anode mud is 3 to 7:

100.

4. The tellurium recovery process based on lead anode mud according to claim 1, characterized in that: The temperature of the oxidation refining is 500-600°C.

5. The tellurium recovery process based on lead anode mud according to claim 1, characterized in that: The oxidation refining time is 70 to 75 hours.

6. The tellurium recovery process based on lead anode mud according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Lead anode mud is used as raw material, sodium carbonate and pulverized coal are added, and the mass ratio of lead anode mud, sodium carbonate and pulverized coal is 100:8-9:6-7, and then it is sent to the converter for reduction smelting; the produced thin slag is poured out to feed the lead system ingredients, and the molten metal in the furnace is poured into a steel mold and cooled, and then released and added to the antimony converter, the temperature is controlled at 500-600°C, and compressed air is introduced for oxidation refining for 70-75 hours; (2) When the antimony content of the metal solution in the furnace is 3-5%, stop ventilation, control the furnace temperature range to 600-1000°C, introduce compressed air, add sodium hydroxide for oxidation to form tellurium slag, the mass ratio of sodium hydroxide to lead anode mud is 3-7:100, the reaction time is 2-4 hours, and the converter is discharged.

7. The tellurium recovery process based on lead anode mud according to claim 6, characterized in that: The compressed air has a pressure of 0.3-0.5 MPa and a flow rate of 100-200 m 3 / h.

8. The tellurium recovery process based on lead anode mud according to claim 6, characterized in that: The mass ratio of the lead anode mud, soda ash and pulverized coal is 100:8:

6.

9. The tellurium recovery process based on lead anode mud according to claim 6, characterized in that: The mass ratio of added sodium hydroxide to lead anode mud is 5:100.