Method for preparing high-grade secondary zinc oxide in rotary kiln through oxygen enriched combustion

Abstract

The invention is a method for preparing high-grade zinc oxide by oxygen-enriched combustion in a rotary kiln. The steps are: preparation of zinc-containing materials: processing zinc-containing raw materials from various sources to make them meet the requirements of zinc-containing 6-20%, Moisture content of 10-20% is required, and the particle size is less than 1cm; Mixture ingredients: mix fuel with zinc-containing materials, the fuel accounts for 25-35% by mass in the mixture or the calorific value of the mixture is 1500-2000 Kcal / kg; put the mixture into the rotary kiln, and blow in oxygen-enriched air for combustion, so that zinc is enriched in the form of zinc oxide in the dust, and iron is enriched in the kiln slag; the dust is collected to obtain secondary zinc oxide products. The invention aims at the complex material rotary kiln volatilization process, first solves the combustion control problem, ensures the combustion temperature, and the kiln condition is stable, and then performs the fuel ratio according to the heat required for the reaction, thereby improving the kiln condition, increasing the combustion efficiency, and the rotary kiln treatment Quantity, secondary zinc oxide powder quality and recovery rate, while reducing energy consumption and saving costs.

Description

technical field

[0001] The invention relates to a method for preparing high-grade zinc oxide by oxygen-enriched combustion in a rotary kiln, and belongs to the technical field of energy-saving and comprehensive recovery of low-grade zinc-containing materials. Background technique

[0002] In the process of traditional zinc sulfide concentrate smelting and extraction of metal zinc, most of the leaching slag adopts pyrolysis volatilization and enrichment method to produce zinc oxide powder. However, in actual production, various zinc-containing secondary resources have zinc-containing grades. Low and high impurity content, the rotary kiln is also used to volatilize and enrich zinc. There are many types of zinc-containing secondary resources, such as smoke dust, leaching slag, pyrotechnical slag, etc., and the shape is powdery, muddy, massive, etc., and the water content fluctuates greatly, resulting in a large temperature change during the combustion and volatilization process...

Examples

example 1

[0016] Example 1. A variety of complex low-zinc materials are mixed with coke powder (5800 kcal) and then added to a Ф3.2*50m rotary kiln to produce secondary zinc oxide powder. The composition of each material is shown in Table 1:

[0017] Table 1 Composition of zinc-containing materials (raw materials) (%)

[0018] name

[0019] Note: The unit of indium (In) content in the table is g / t, the same below.

[0020] Each material is mixed with coke powder, and the coke powder accounts for 31% by mass of the mixture. The mixture added per hour is 13.8 tons, and the Roots blower is used to feed 4800Nm during the combustion process. 3 / h, the oxygen-enriched air with an oxygen content of 26.3%, the temperature in the kiln is 1240°C, and the negative pressure in the kiln is 45Pa. The components of the produced boiler powder, bag powder and kiln slag are shown in Table 2:

[0021] Table 2 Zinc-containing material (product) composition (%)

[0022] name

[0023]...

example 2

[0027] Example 2. A variety of complex low-zinc materials are mixed with coke powder (5700 kcal) and then added to a Ф2.5*38m rotary kiln to produce secondary zinc oxide powder. The composition of each material is shown in Table 4:

[0028] Table 4 Composition of zinc-containing materials (raw materials) (%)

[0029] name

Zn

Pb

In

Fe

S

Ag

Ca

Cl

Gas Ash

8.24

0.91

145

22.72

1.87

13

2.88

2.57

Neutralize iron slag

11.2

/

115

10.3

16.0

/

18.2

/

zinc lead slag

5.84

1.92

165

27.01

5.27

41

8.7

/

oxide ore

23.24

5.59

31

10.74

0.34

84

4.26

/

Back to powder

20.53

4.08

228

12.44

2.91

20

2.51

2.52

[0030] Each material is mixed with coke powder, and the coke powder accounts for 34% by mass of the mixture. The mixture added per hour is 7.2 tons, and the Roots blower is used to feed 3800Nm duri...

technical field

[0001] The invention relates to a method for preparing high-grade zinc oxide by oxygen-enriched combustion in a rotary kiln, and belongs to the technical field of energy-saving and comprehensive recovery of low-grade zinc-containing materials. Background technique

[0002] In the process of traditional zinc sulfide concentrate smelting and extraction of metal zinc, most of the leaching slag adopts pyrolysis volatilization and enrichment method to produce zinc oxide powder. However, in actual production, various zinc-containing secondary resources have zinc-containing grades. Low and high impurity content, the rotary kiln is also used to volatilize and enrich zinc. There are many types of zinc-containing secondary resources, such as smoke dust, leaching slag, pyrotechnical slag, etc., and the shape is powdery, muddy, massive, etc., and the water content fluctuates greatly, resulting in a large temperature change during the combustion and volatilization process...

Examples

example 1

[0016] Example 1. A variety of complex low-zinc materials are mixed with coke powder (5800 kcal) and then added to a Ф3.2*50m rotary kiln to produce secondary zinc oxide powder. The composition of each material is shown in Table 1:

[0017] Table 1 Composition of zinc-containing materials (raw materials) (%)

[0018] name

[0019] Note: The unit of indium (In) content in the table is g / t, the same below.

[0020] Each material is mixed with coke powder, and the coke powder accounts for 31% by mass of the mixture. The mixture added per hour is 13.8 tons, and the Roots blower is used to feed 4800Nm during the combustion process. 3 / h, the oxygen-enriched air with an oxygen content of 26.3%, the temperature in the kiln is 1240°C, and the negative pressure in the kiln is 45Pa. The components of the produced boiler powder, bag powder and kiln slag are shown in Table 2:

[0021] Table 2 Zinc-containing material (product) composition (%)

[0022] name

[0023]...

example 2

[0027] Example 2. A variety of complex low-zinc materials are mixed with coke powder (5700 kcal) and then added to a Ф2.5*38m rotary kiln to produce secondary zinc oxide powder. The composition of each material is shown in Table 4:

[0028] Table 4 Composition of zinc-containing materials (raw materials) (%)

[0029] name

Zn

Pb

In

Fe

S

Ag

Ca

Cl

Gas Ash

8.24

0.91

145

22.72

1.87

13

2.88

2.57

Neutralize iron slag

11.2

/

115

10.3

16.0

/

18.2

/

zinc lead slag

5.84

1.92

165

27.01

5.27

41

8.7

/

oxide ore

23.24

5.59

31

10.74

0.34

84

4.26

/

Back to powder

20.53

4.08

228

12.44

2.91

20

2.51

2.52

[0030] Each material is mixed with coke powder, and the coke powder accounts for 34% by mass of the mixture. The mixture added per hour is 7.2 tons, and the Roots blower is used to feed 3800Nm duri...