Comprehensive recovery process for high-sulfur-content zinc hydrometallurgy slag

Abstract

The invention relates to the technical field of lead-containing zinc oxide recovery, and discloses a comprehensive recovery process for high-sulfur-content zinc hydrometallurgy slag, which comprises the following steps: on the premise of ensuring that the kiln tail temperature is 460-500 DEG C and the kiln head temperature is 960-1020 DEG C, changing and adjusting the coal injection amount and the blast volume of secondary air according to the temperature change condition and the impurity-containing condition of small-kiln calcine and high-lead smoke dust, thereby realizing the comprehensive recovery of the high-sulfur-content zinc hydrometallurgy slag. The redox atmosphere in the rotary kiln is adjusted, smooth reaction in the kiln is guaranteed, the treatment efficiency of the sulfur-containing zinc hydrometallurgy slag is improved, the content of iron and sulfur in a zinc oxide product is reduced, the technological process is simple, the reaction efficiency is high, energy is saved, environment friendliness is achieved, and the lead and zinc recovery rate and the pyrite removal rate are high.

Description

Technical Field

[0001] The present invention relates to the technical field of lead-containing zinc oxide recovery, and particularly to a comprehensive recovery process for high-sulfur hydrometallurgical zinc slag. Background Art

[0003] In recent years, with the use of zinc concentrates with complex compositions in the hydrometallurgical zinc system, the sulfur content in the leaching residue has gradually increased. After the high-sulfur zinc-containing slag is calcined in a volatilization kiln, the secondary zinc oxide contains Fe: 8% - 12%, S: 11% - 15%, the zinc oxide contains Fe: 6% - 8%, S: 8% - 10%. The quality of the zinc oxide entering the hydrometallurgical zinc system is severely affected. It is necessary to add more manganese ore in the hydrometallurgical zinc process to oxidize Fe, S, etc., resulting in the continuous accumulation and increase of manganese ions in the hydrometallurgical zinc system, causing a huge impact on the continuous operation of the hydrometallurgical zinc system. Especially, the loss of manganese powder in the leaching system increases sharply, and the leaching process is greatly affected. Summary of the Invention

[0004] The purpose of the present invention is to provide a comprehensive recovery process for high-sulfur hydrometallurgical zinc slag to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A comprehensive recovery process for high-sulfur hydrometallurgical zinc slag, comprising the following steps:

[0007] S1: Ensure that the temperature at the kiln tail is 460 - 500 °C and the temperature at the kiln head is 960 - 1020 °C;

[0008] S2: Adjust the coal injection amount to reduce the entry of reducing agents in the kiln, and gradually reduce the coal feeding frequency according to the impurity content of zinc oxide calcine;

[0009] S3: Increase the air volume of the secondary air blast at the kiln head to increase the entry of oxygen;

[0010] S4: Adjust the induced air volume according to the temperature change and the impurity content of the small kiln calcine and high-lead dust to ensure smooth reaction in the kiln.

[0011] In the step S2, the mixing ratio of pulverized coal to hydrometallurgical zinc slag is 20 - 30 tons of pulverized coal per 100 tons of hydrometallurgical zinc slag.

[0012] In the step S3, the air volume of the secondary air blast at the kiln head is adjusted according to the temperature detected at the kiln tail. The secondary air volume is 21% - 27% of the pulverized coal injection amount, and the air blast in the rotary kiln keeps the temperature at the kiln tail not lower than 500 °C and the temperature at the kiln head not lower than 1020 °C.

[0013] In step S1, to ensure the full combustion of pulverized coal, the air volume of the induced draft fan is 5 - 12 Hz, and the rotational speed of the rotary kiln is 10 - 15 Hz.

[0014] The zinc oxide calcine produced by roasting is packaged and stored in ton bags. The sulfur content in the zinc oxide is less than 2%, and the iron content is less than 5%.

[0015] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0016] By changing and adjusting the coal injection volume and the air volume of the secondary air, the present invention adjusts the redox atmosphere in the rotary kiln, ensures the smooth reaction in the kiln, improves the treatment efficiency of sulfur-containing wet zinc smelting slag, reduces the iron and sulfur content in the zinc oxide product, has a simple process, high reaction efficiency, energy conservation and environmental protection, and high recovery rates of lead and zinc and removal rates of sulfur and iron. Specific Embodiments

[0017] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, rather than all, of the embodiments of the present invention.

[0018] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0019] The present invention provides a comprehensive recovery process for high-sulfur wet zinc smelting slag, including the following:

[0020] S1: On the premise of ensuring that the temperature at the kiln tail is 460 - 500 °C and the temperature at the kiln head is 960 - 1020 °C, adjust the coal injection volume, reduce the entry of reducing agents in the kiln, and gradually reduce the coal feeding frequency according to the impurity content of the zinc oxide calcine.

[0021] S2: On the premise of ensuring that the temperature at the kiln tail is 460 - 500 °C and the temperature at the kiln head is 960 - 1020 °C, increase the air volume of the secondary air at the kiln head, increase the entry of oxygen, and increase the secondary air volume according to the temperature at the kiln tail.

[0022] S3: On the premise of ensuring that the temperature at the kiln tail is 460 - 500 °C and the temperature at the kiln head is 960 - 1020 °C, adjust the induced air volume according to the temperature change and the impurity content of the small kiln calcine and high-lead dust to ensure the smooth reaction in the kiln.

[0023] The mixing ratio of pulverized coal to wet zinc smelting slag is 20 - 30 tons of pulverized coal per 100 tons of wet zinc smelting slag.

[0024] The input amount of secondary air at the kiln head is adjusted according to the detected temperature at the kiln tail. The secondary air volume is 21% - 27% of the pulverized coal injection amount, and the air injection in the rotary kiln keeps the temperature at the kiln tail not lower than 500°C and the temperature at the kiln head not lower than 1020°C.

[0025] To ensure the full combustion of pulverized coal, the air volume of the induced draft fan is 5 - 12 Hz, and the rotational speed of the rotary kiln is 10 - 15 Hz.

[0026] The zinc oxide calcine produced by roasting is packaged and stored in ton bags. The sulfur content in the zinc oxide is less than 2%, and the iron content is less than 5%.

[0027] Example 1

[0028] Adjust the coal injection amount to ensure that the ratio of pulverized coal to zinc hydrometallurgy slag is 100:30, the secondary air volume is 21% of the pulverized coal amount, the temperature at the kiln tail is 500°C, and the temperature at the kiln head is 1020°C. The iron, sulfur, zinc, and lead contents of the obtained calcine are shown in Table 1.

[0029] Table 1 Composition of Calcine %

[0030] Zn Pb Fe S 59.53 12.89 3.69 1.19 60.42 8.38 4.31 1.49

[0031] Example 2

[0032] Adjust the coal injection amount to ensure that the ratio of pulverized coal to zinc hydrometallurgy slag is 100:20, the secondary air volume is 27% of the pulverized coal amount, the temperature at the kiln tail is 460°C, and the temperature at the kiln head is 960°C. The iron, sulfur, zinc, and lead contents of the obtained calcine are shown in Table 2.

[0033] Table 2 Composition of Calcine %

[0034] Zn Pb Fe S 53.77 12.07 4.74 1.67 53.50 11.27 3.38 1.51

[0035] Example 3

[0036] Adjust the coal injection amount to ensure that the ratio of pulverized coal to zinc hydrometallurgy slag is 100:25, the secondary air volume is 24% of the pulverized coal amount, the temperature at the kiln tail is 480°C, and the temperature at the kiln head is 1000°C. The iron, sulfur, zinc, and lead contents of the obtained calcine are shown in Table 3.

[0037] Table 3 Composition of Calcine %

[0038] Zn Pb Fe S 51.43 10.22 4.65 0.99 62.44 7.26 3.00 0.81

[0039] It can be seen from Examples 1 - 3 that on the premise of ensuring that the temperature at the kiln tail is 460 - 500°C and the temperature at the kiln head is 960 - 1020°C, with the adjustment of zinc hydrometallurgy slag and secondary air volume, the iron content in the obtained calcine can be reduced to less than 5%, and the sulfur can be reduced to less than 2%.

Claims

1. A comprehensive recovery process for high-sulfur zinc hydrometallurgy slag, characterized in that, It includes the following steps: S1: Ensure that the temperature at the kiln tail is 460 - 500 °C and the temperature at the kiln head is 960 - 1020 °C; S2: Adjust the coal injection amount, reduce the entry of reducing agents in the kiln, and gradually reduce the coal feeding frequency according to the impurity content of zinc oxide calcine; S3: Increase the air volume of the secondary air blower at the kiln head to increase the entry of oxygen; S4: Adjust the induced draft volume according to the temperature change and the impurity content of small kiln calcine and high-lead dust to ensure smooth reaction in the kiln.

2. The comprehensive recovery process of high-sulfur zinc hydrometallurgy slag according to claim 1, characterized in that: In the step S2, the mixing ratio of pulverized coal and zinc hydrometallurgy slag is 20 - 30 tons of pulverized coal per 100 tons of zinc hydrometallurgy slag.

3. A comprehensive recovery process for high-sulfur zinc hydrometallurgy slag according to claim 1, characterized in that: In the step S3, the air volume of the secondary air blower at the kiln head is adjusted according to the temperature detected at the kiln tail. The secondary air volume is 21% - 27% of the pulverized coal injection amount, and the air blowing in the rotary kiln keeps the temperature at the kiln tail not lower than 500 °C and the temperature at the kiln head not lower than 1020 °C.

4. A comprehensive recovery process for high-sulfur zinc hydrometallurgy slag according to claim 1, characterized in that: In the step S1, to ensure full combustion of pulverized coal, the air volume of the induced draft fan is 5 - 12 Hz, and the rotational speed of the rotary kiln is 10 - 15 Hz.

5. A comprehensive recovery process for high-sulfur zinc hydrometallurgy slag according to claim 1, characterized in that: The zinc oxide calcine produced by roasting is packaged and stored in ton bags. The sulfur content in the zinc oxide is lower than 2%, and the iron content is lower than 5%.