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Pre-heating method of sulfate slag pellet ore

A technology of sulfuric acid slag pellets and sulfuric acid slag raw pellets, which is applied in the preheating field of pellets, and can solve the problems of affecting the process, cracks, and easy formation of over-wet layers by pellets.

Active Publication Date: 2010-02-10
ZHONGYE-CHANGTIAN INT ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The inventors have found that if the grate machine-rotary kiln in the prior art is used to prepare sulfuric acid slag pellets, in the first draft drying section, the pellets in the lower part of the material layer are likely to form an over-wet layer, and the pellets are easily crushed , resulting in cracks, affecting subsequent processes

Method used

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  • Pre-heating method of sulfate slag pellet ore
  • Pre-heating method of sulfate slag pellet ore
  • Pre-heating method of sulfate slag pellet ore

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] The main design parameters of the grate-rotary kiln are as follows:

[0073] Grate machine specifications: 4m (width) × 37.5m (length), blast drying section length 7.5m, set temperature 230°C, material surface wind speed 1.5m / s; suction drying section length 7.5m, set temperature 360°C , the wind speed at the material surface is 1.2m / s; the length of the first preheating section is 7.5m, the set temperature is 700°C, and the wind speed at the material surface is 1.0m / s; the length of the second preheating section is 15m, and the set temperature is 1200°C. The surface wind speed is 0.7m / s.

[0074] Rotary kiln set temperature: 1350°C.

[0075] Ring cooler specifications: diameter 12.5m, width 2.2m, effective cooling area 68m 2 ; The cooling area of ​​the first cooling section C1 is 25m 2 , the cooling area of ​​the second cooling section is 23m 2 , the cooling area of ​​the third cooling section is 20m 2 .

[0076] The flue gas discharged from the first cooling sec...

Embodiment 2

[0081] The difference from Example 1 is that the following process design parameters have been changed: the set temperature of the blast drying section is 220°C, and the wind speed of the material surface is 1.4m / s; the set temperature of the draft drying section is 340°C, and the wind speed of the material surface is 1.3m / s ,; The set temperature of the first preheating section is 750°C, and the wind speed of the material surface is 1.1m / s; the set temperature of the second preheating section is 1200°C, and the wind speed of the material surface is 0.7m / s; ; Other parameters are identical with embodiment 1.

[0082] Raw materials: take 30 parts by weight of sulfuric acid slag after roller milling, 70 parts by weight of hematite, 1 part by weight of bentonite, 6 parts by weight of limestone and water to make pellets in a disc granulator. The obtained green pellets were tested, and the performance indexes were as follows: the drop strength was 7.3 times / 0.5m, the water content ...

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Abstract

The invention provides a pre-heating method of sulfate slag pellet ore. The method comprises the steps of: sending sulfate slag green pellets into a chain grate for to be subject to forced air drying,draft air drying, primary pre-heating and secondary pre-heating in sequence; taking the fume discharged by a rotary kiln as the hot air source during the secondary pre-heating; taking the fume discharged by secondary cooling of a cooler as the hot air source during the primary pre-heating; taking the fume discharged after secondary pre-heating as the hot air source during the draft air drying; and taking the fume discharged by tertiary cooling of the cooler as the hot air source during the forced air drying. The invention firstly carrying out forced air drying on the sulfate slag pellets, when the moisture of the green pellets move upwards from the bottom of the material layer, thus preventing an overdamp layer from being formed on the bottom layer of the material layer, avoiding the appearance of flattened or cracked green pellets on the bottom of the material layer and ensuring the following procedures to be carried out smoothly.

Description

technical field [0001] The invention relates to a preheating method for pellets, in particular to a preheating method for sulfuric acid slag pellets. Background technique [0002] Pellet is one of the main raw materials for blast furnace ironmaking and direct reduced iron. Pellets have several advantages over sinter. For example, the mechanical strength of pellets in the cold state is higher than that of sintered ore, so it is not easy to be broken and cracked during transportation, loading and unloading and storage, with less consumption and less powder produced, which is conducive to improving the air permeability of the blast furnace material column and making the furnace The airflow inside is evenly distributed. In the prior art, there are mainly three methods for preparing pellets, namely: the method of producing pellets in a shaft furnace, the method of preparing pellets by a belt roaster, and the method of preparing pellets by a chain grate-rotary kiln method. Comp...

Claims

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Application Information

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IPC IPC(8): C22B1/14
Inventor 王赛辉贺新华丁智清李文辉沈维民宁德乙林恩玉
Owner ZHONGYE-CHANGTIAN INT ENG CO LTD
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