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Calcining method of low carbon high-activity lime

A high-activity, lime technology, applied in the field of material preparation, can solve problems affecting the quality of low-carbon high-activity lime, difficult gas discharge, slow heat transfer rate, etc., to increase lime utilization, reduce foamy slag and splashing, The effect of reducing the amount of steel scrap

Active Publication Date: 2013-06-26
JIAYUGUAN DAYOU JIAMEI CALCIUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the limestone is calcined by the traditional process, the particle size range of the limestone is relatively large. During the calcining process, because the heat transfer rate of the lime is much smaller than that of the limestone, as the outer lime layer becomes thicker, the inner limestone The heat transfer rate of the particles will become slower and slower, and the calcination time will be longer, and the long-term high temperature will make the surface of the limestone over-fired and "ceramized", and the CO generated during calcination will 2 The gas is difficult to discharge, the decarburization is not complete, and a raw burn is formed
Not only waste energy, but also affect the quality of low-carbon high-activity lime

Method used

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  • Calcining method of low carbon high-activity lime

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The limestone particles with a particle size of 20mm are sent to the preheater of the rotary kiln used in the traditional process for preheating for 40 minutes, so that the surface and center temperature of the limestone particles reach 800°C, and then enter the rotary kiln body to raise the temperature to 1000°C. Continue to heat up and burn low-carbon high-activity lime at 1100°C. The length of the burning zone is no more than 35m; The mixed fuel composed of high-injection steam coal with a value of 26000kj / kg is co-fired. After testing, the crystal particle size of the low-carbon high-activity lime is 1.39 cm 2 / g, the density is 1.57 g / cm 3 , The specific surface area is 16300 cm 2 / g, porosity 48.0%, shrinkage 17%.

Embodiment 2

[0035] The limestone particles with a particle size of 40mm are sent to the preheater of the rotary kiln used in the traditional process for preheating for 45 minutes, so that the surface and center temperature of the limestone particles reach 850°C, and then enter the rotary kiln body and then raise the temperature to 930°C. After that, continue to heat up, and burn low-carbon high-activity lime at a temperature of 1200°C. The length of the burning zone is not more than 35m; The mixed fuel composed of high-injection steam coal with a value of 27000kj / kg is co-fired. After testing, the crystal particle size of the low-carbon high-activity lime is 1.1 cm 2 / g, the density is 1.44 g / cm 3 , The specific surface area is 19860 cm 2 / g, porosity 52.0%, shrinkage 13%.

Embodiment 3

[0040] The limestone particles with a particle size of 30mm are sent to the preheater of the rotary kiln used in the traditional process to preheat for 35 minutes, so that the surface and center temperature of the limestone particles reach 825°C, and then enter the rotary kiln body and then raise the temperature to 850°C. After that, continue to heat up and burn low-carbon high-activity lime at a temperature of 1000°C. The length of the burning zone is not more than 35m; The mixed fuel composed of high-injection thermal coal with a value of 26500kj / kg is co-fired.

[0041] After testing, the crystal particle size of the low-carbon high-activity lime is 1.27 cm 2 / g, the density is 1.51 g / cm 3 , The specific surface area is 17800 cm 2 / g, porosity 50.0%, shrinkage 16%.

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Abstract

The invention provides a calcining method of low carbon high-activity lime. The method comprises the following steps of: feeding limestone particles to a preheater for preheating for 40+ / -5min, and feeding to a rotary kiln to re-heat to 850-1000 DEG C after the surface and central temperatures of the limestone particles reach 800-850 DEG C; and then, calcining the limestone particles into low carbon high-activity lime in a calcining belt which is not longer than 35m at 1000-1200 DEG C. According to the calcining method, the decomposition rate of limestone is improved, the heat loss is reduced, the fuel utilization ratio is improved, and the resources are saved. In the pre-heating stage, the limestone particles are internally and externally preheated to critical decomposition temperature, and the particles are quickly heated so that not only the internal temperature of the particles reaches to a high temperature beneficial to CO2 emission, thereby reducing the residual quantity of CO2 in lime, but also the external temperature cannot be overhigh and the compact layers or vitreous layers preventing CO2 from escaping and caused by over-calcining are not formed on the surface of the lime.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and relates to a method for calcining lime with limestone, in particular to a method for calcining low-carbon high-activity lime used in stainless steel smelting. Background technique [0002] In stainless steel smelting, it is necessary to use: 1) high activity; 2) large specific surface area, fast dissolution rate in slag; 3) small bulk density; 4) small crystal size; Low-carbon high-activity lime with high yield. This low-carbon high-activity lime is usually obtained by calcining granular limestone in a rotary kiln. When the limestone is calcined by the traditional process, the particle size range of the limestone is relatively large. During the calcining process, because the heat transfer rate of the lime is much smaller than that of the limestone, as the outer lime layer becomes thicker, the inner limestone The heat transfer rate of the particles will become slower and slower,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B2/10
Inventor 高宝署李燕君段元春
Owner JIAYUGUAN DAYOU JIAMEI CALCIUM IND