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A kind of rotary kiln redox volatilization method containing germanium, indium and zinc raw materials

A rotary kiln and raw material technology, applied in the field of redox volatilization of rotary kiln, can solve the problems of increased energy consumption, high slag melting temperature, easy kiln closure, frequent maintenance and other problems, to achieve increased alkalinity, reduced silicon dioxide wrapped germanium, Favorable effect of alkaline production

Active Publication Date: 2021-01-29
GUIZHOU HONGDA ENVIRONMENTAL PROTECTION TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Metal zinc evaporates in a large amount at about 900°C and is oxidized into zinc oxide. Since there is no price change, there is no low-temperature sublimation phenomenon, and the volatilization rate can only increase with the increase of temperature. It can reach about 98% at 1250-1300°C. It will not significantly help the volatilization of metal zinc, but will increase energy consumption and damage the furnace body. The high temperature of slag melting will easily cause the kiln to freeze, resulting in unsmooth production, short furnace life, and frequent maintenance. Therefore, the germanium and indium components in the raw materials After being fully oxidized to a high-valent oxide, it is difficult to volatilize into the dust for enrichment and recovery. At the same time, the amount of silicon dioxide in the dust at high temperature is much larger than that of germanium, and the chemical properties of silicon and germanium are similar, and it has an isoelectronic molecular structure. Isomerization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The zinc leaching slag produced by an enterprise contains 8.5% zinc, 0.015% germanium, 0.035% indium, and 5.3% silicon dioxide. The dry weight of the zinc leaching slag is mixed with coke powder according to 40% of the dry weight of the zinc leaching slag, and then calcium oxide / silica = 1.1 Add calcium oxide and mix evenly, add water and stir to make the water content of the material 12%; granulate through a disc granulator to make the particle size 10-50mm, and add to the rotary kiln while granulating; the feeding amount is 3t / h.

[0033] The length of the feeding and preheating section (kiln tail) of the rotary kiln is 15% of the total length, the temperature is 850±10°C, the length of the oxidation-reduction reaction section (in the kiln) accounts for 75% of the total length, the temperature is 1250±20°C, and the cooling and slag discharge section (kiln The kiln head) accounts for 10% of the total length, and the temperature is 900±10°C; the kiln head is equipped wit...

Embodiment 2

[0036] A low-grade zinc oxide ore contains 12.5% ​​of zinc, 0.0058% of germanium, 0.0072% of indium, 5.8% of calcium oxide, 18.2% of silicon dioxide, and 1.8% of iron; after grinding to 100 mesh, it is mixed with reduced coal at 42% by weight, Add calcium oxide and mix evenly according to alkaline matter / acidic matter = 1.1, spray water to granulate, the water content of raw material granules is 15%, add to the rotary kiln, control the length of the kiln tail to be 18% of the total length, and the temperature is 880-900°C. The length of the kiln is 70% of the total length, the temperature is 1300±10°C, the length of the kiln head is 12% of the total length, the temperature is 950°C-970°C; the air blast pressure is 4.5kg / ㎡, and the air volume is 420m 3 / ton of raw materials; gas blowing pressure 1kg / ㎡, consumption 100m 3 / ton of raw materials; the oxygen content of oxygen-enriched air is 45%, the blowing pressure is 2kg / ㎡, and the air volume is 230m 3 / ton of raw materials;...

Embodiment 3

[0038] Carry out conventional rotary kiln redox volatilization test with the raw materials of Example 1 and Example 2 respectively, control the alkalinity of the raw materials into the furnace to be 0.85-0.9, moisture 5-8%, control the kiln tail to be 10-15% of the total length, and the temperature to be 700-800°C ; In the kiln, the total length is 75-80%, the temperature is 1200-1300°C, and the kiln head is 5-10% of the total length, and the temperature is 900±10°C. The air blown into the kiln head has a wind pressure of 4.5kg / ㎡ and an air volume of 500m 3 / ton of raw materials, no coal gas and oxygen-enriched air are blown in, the negative pressure of flue gas discharge is 50Pa, and the zinc oxide dust obtained by dust collection contains 45.5%, 47.3% zinc, 0.018% germanium, 0.0063%, 0.021% indium, 0.008%; kiln slag Zinc content is 1.25%, 1.32%, germanium 0.085%, 0.0092%, indium 0.093%, 0.0062%.

[0039] In order to improve the volatilization recovery rate of germanium and...

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PUM

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Abstract

The invention relates to the technical field of non-ferrous metal recycling, in particular to a method for redox volatilization of a rotary kiln containing raw materials containing germanium, indium and zinc; comprising the following steps: (1) adding reduced coal or coke after crushing the raw materials containing germanium, indium and zinc powder, then add any one or more of calcium oxide, silica, calcium hydroxide powder, and mix evenly; (2) After adding water and granulating, feed to the rotary kiln; (3) Through the three-stage temperature control treatment of the rotary kiln; (4) The kiln head is provided with three gas blowing pipes of different angles and lengths for air supply; (5) The negative pressure of the flue gas discharge of the rotary kiln is controlled by combining conventional bag dust collection and electrostatic dust collection; through the method of the present invention, the The content of germanium, indium and zinc in the kiln slag is discharged, so that germanium, indium and zinc in raw materials containing germanium, indium and zinc can all achieve high volatilization and high enrichment, prevent silicon dioxide from wrapping and avoid producing tetragonal crystals Germanium, which is convenient for subsequent processes to smelt and recover germanium.

Description

technical field [0001] The invention relates to the technical field of nonferrous metal recovery, in particular to a rotary kiln redox volatilization method for raw materials containing germanium, indium and zinc. Background technique [0002] Indium (In) reserves are scarce in the world, and its content in the earth's crust is similar to that of silver, which is 1×10 -5 , but the output is only 1% of silver, so far no single or natural indium deposits with indium as the main component have been found. At present, the minerals with industrial recovery value of indium are mainly sphalerite. The global reserves of indium are about 16,000 to 19,000 tons, and the supply of indium is mainly divided into primary indium and recycled indium. Use noble metal In and tin oxide In 2 o 3 The tin-doped indium oxide (hereinafter referred to as IOC) target is made of a conductive transparent film through a magnetron sputtering process, which is used for submarines, tanks, aviation and st...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B41/00C22B58/00C22B19/04C22B5/16
CPCC22B5/16C22B19/04C22B41/00C22B58/00
Inventor 李世平王志斌韦国龙卢宇
Owner GUIZHOU HONGDA ENVIRONMENTAL PROTECTION TECHNOLOGY CO LTD