Method for improving strength of pellets

A pelletizing and strength technology, which is applied in the field of ironmaking raw material production technology, can solve the problems of not effectively improving the strength of pellets, changing the use of pellets, and affecting the grade of pellets, so as to shorten the preheating and drying time, The effect of increasing the strength of pellets and increasing the strength

Active Publication Date: 2013-12-18
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The methods used in the above documents and patents are different, but the core is to add carbon or add flux, so the solution is limited, and it will affect the grade of pellets, and even change the use of pellets
In addition, from the perspective of oxidized pellets, the above method cannot effectively improve the strength of pellets

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The magnetite concentrate with a total mass percentage of 20% is fully mixed with the external bentonite which accounts for 0.45% of the total amount of magnetite concentrate and non-magnetite concentrate raw materials; The magnetite concentrate and the non-magnetite concentrate raw material total amount of 1.05% external bentonite are fully mixed. Add 16% of the mixed magnetite concentrate, 80% of the hematite concentrate, and 4% of the magnetite concentrate into the pelletizing plate in three steps to make pellets. Distribute the prepared green balls into a pressure-resistant container, and pass in compressed air. When the pressure of the container reaches 7.5MPa, keep it for 1 minute, and finally preheat, dry, roast and cool.

[0020] Table 1 shows the performance comparison of the pellets produced by compound pelletizing in Example 1 and the comparative example (20% magnetite concentrate and 80% hematite concentrate).

[0021] Table 1 Composite pelletizing in Examp...

Embodiment 2

[0024] The total mass percentage is 50% of the magnetite concentrate and the external bentonite which accounts for 0.63% of the total amount of magnetite concentrate and non-magnetite concentrate raw materials is fully mixed; the hematite whose particle size is less than 200 mesh ≥ 95% is 30%, brown 20% of iron ore is fully mixed with external bentonite which accounts for 0.77% of the total raw materials of magnetite concentrate and non-magnetite concentrate. Add 20% of magnetite concentrate, non-magnetite concentrate (30% of hematite and 20% of limonite) and 30% of magnetite concentrate into the pelletizing disc in three steps. Distribute the prepared green balls into a pressure-resistant container, and pass in compressed air. When the pressure of the container reaches 5MPa, keep it for 1.8 minutes, and finally preheat, dry, roast and cool.

[0025] Table 2 shows the performance comparison of the pellets produced by compound pelletizing in Example 2 and the comparative exampl...

Embodiment 3

[0029] Mix magnetite concentrate with external bentonite which accounts for 0.42% of the total raw materials of magnetite concentrate and non-magnetite concentrate; mix hematite concentrate, limonite, and siderite with particle size less than 200 mesh ≥ 95% The mixed ore of the ore is fully mixed with the external bentonite which accounts for 0.88% of the total amount of magnetite concentrate and non-magnetite concentrate. The total mass percentage of the magnetite concentrate is 60%, and the total mass percentage of the three non-magnetite concentrates is 40%. % (including 20% ​​hematite concentrate, 10% limonite concentrate, and 10% siderite), and the total mass of bentonite is 1.3%. Add 36% of the magnetite concentrate, 40% of the mixed ore of three non-magnetite concentrates, and 24% of the magnetite concentrate into the pelletizing disc in three steps. Distribute the prepared green balls into a pressure-resistant container, and pass in compressed air. When the pressure of...

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PUM

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Abstract

The invention provides a method for improving the strength of pellets. The method comprises the following steps: respectively and independently mixing magnetite concentrates and non-magnetite concentrates with externally matched bentonite uniformly; pelletizing, wherein pellets comprise not less than 20% of magnetite concentrates and not more than 80% of non-magnetite concentrates, and in the pelletizing process, the magnetite concentrates added for the first time account for 40-80% of total addition of the magnetite concentrates, the mixture of the non-magnetite concentrates and bentonite is added for the second time, the remaining magnetite concentrates are added for the third time, and 1.3-1.5wt% of bentonite is added in the pelletizing process to serve as a binder; carrying out pressure increase and reduction treatment on the pellets. The method has the beneficial effects that the calcination temperatures of ores at the middle layer and crystal bridge connection between the pellets can be improved, the content and existing state of water in the pellets can be changed, the preheating and drying time can be shortened, the preheating and drying temperatures can be reduced, the burst properties of the pellets can be reduced, the strength of the pellets can be improved, the use proportions of hematite, limonite and siderite in the pellets can be increased, and the production cost of the pellets can be lowered.

Description

technical field [0001] The invention belongs to the field of production technology of ironmaking raw materials, and in particular relates to a method for improving the strength of pellets. Background technique [0002] Oxidized pellets are an important part of ironmaking raw materials, and their combination with high-basicity sinter constitutes the main charge structure of blast furnaces in China, and the proportion of use in domestic blast furnaces is generally about 25%. The raw materials for producing pellets are generally iron ore concentrates that have undergone flotation or magnetic separation, and the particle size requirements are relatively fine, and the pelletizing performance is better. [0003] At present, most domestic pelletizing plants use magnetite concentrate to produce pellets. The main reason is that the magnetite concentrate has fine particle size and good pelletizing performance. During the oxidation roasting process, the required roasting temperature is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B1/14C22B1/243
Inventor 刘杰周明顺翟立委张辉徐礼兵童晓宇
Owner ANGANG STEEL CO LTD
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