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Preheating roasting desulfuration and rapid cooling technology for high-sulphur bauxite in suspended state

A high-sulfur bauxite, rapid cooling technology, applied in the chemical industry, sustainable manufacturing/processing, alumina/hydroxide, etc., can solve the problem of small gas-solid two-phase contact area, increased energy consumption during roasting time, transmission Problems such as low heat and mass transfer rate, to achieve short roasting time, small footprint, and good thermal stability

Active Publication Date: 2013-11-27
XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The roasted ores obtained by the above roasting methods can all meet the production requirements of the subsequent alumina process, but they all have the problem of long roasting time. Prolonging the roasting time will not only increase the energy consumption per unit product, but also make the α -Al 2 o 3 The crystal structure is more stable, which is not conducive to the subsequent improvement of the dissolution rate of alumina
Rotary kiln, fluidized bed furnace and fluidized bed all have the disadvantages of large-scale equipment, long residence time of materials, small production capacity and "over-burning" or "under-burning" of a single machine. The operation requirements are strict during bed roasting. The materials in the rotary kiln are in a semi-accumulated state, and the contact area of ​​the gas-solid two-phase is small, resulting in a low heat and mass transfer rate.

Method used

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  • Preheating roasting desulfuration and rapid cooling technology for high-sulphur bauxite in suspended state
  • Preheating roasting desulfuration and rapid cooling technology for high-sulphur bauxite in suspended state
  • Preheating roasting desulfuration and rapid cooling technology for high-sulphur bauxite in suspended state

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Set A / S to 5.97, S T The high-sulfur bauxite powder with a content of 1.35% and -200μm accounts for 90% is sent to the suspension state rapid roasting desulfurization device, and the temperature of the three-stage preheating system: 165 ° C ~ 545 ° C; the powder enters the external circulation suspension furnace for roasting , the temperature in the furnace is 550°C-630°C, and the oxygen content is 9.50%-9.88%; the powder is rapidly cooled in the first-stage air cooling system, and the temperature of the cooling system is 230°C-420°C to obtain low-temperature roasted ore. Process route such as figure 1 As shown, the analysis results of raw materials and roasted ore are as follows:

[0035]

[0036] The dissolution temperature is 260°C, the lime addition is 10%, the dissolution time is 60 minutes, and the dissolution liquid molecular ratio is 1.45. The A / S of the red mud is about 1.2, and the N / S of the red mud is about 0.40. The actual dissolution rate was 79.6%, a...

Embodiment 2

[0038] Set A / S to 6.45, S T The high-sulfur bauxite powder with a content of 1.40% and -200μm accounting for 90% is sent to the suspension state rapid roasting desulfurization device, and the temperature of the three-stage preheating system is 180 ° C ~ 625 ° C; the powder enters the external circulation suspension furnace for roasting, The temperature in the furnace is 650°C to 710°C, and the oxygen content is 8.50% to 9.28%. The powder is rapidly cooled in a three-stage air cooling system, and the temperature of the cooling system is 80°C to 510°C to obtain low-temperature roasted ore. Process route such as figure 1 As shown, the analysis results of raw materials and roasted ore are as follows:

[0039]

[0040]

[0041] The dissolution temperature is 260°C, the lime addition is 10%, the dissolution time is 60 minutes, and the dissolution liquid molecular ratio is 1.45. The A / S of the red mud is about 1.21, and the N / S of the red mud is about 0.50. The actual dissolu...

Embodiment 3

[0043] Set A / S to 6.2, S T The high-sulfur bauxite powder with a content of 4.32% and -200μm accounting for 80% is sent to the suspension state rapid roasting desulfurization device, and the temperature of the three-stage preheating system is 170 ° C ~ 640 ° C; the powder enters the external circulation suspension furnace for roasting, The temperature in the furnace is 660°C-740°C, and the oxygen content is 9.63%-10.88%. The powder is rapidly cooled in a three-stage air cooling system, and the temperature of the cooling system is 80°C-540°C to obtain low-temperature roasted ore. SO in exhaust gas 2 The volume concentration is 4950-5230ppm. Process route such as figure 1 As shown, the analysis results of raw materials and roasted ore are as follows:

[0044]

[0045] The dissolution temperature is 260°C, the lime addition is 10%, the dissolution time is 60 minutes, and the dissolution liquid molecular ratio is 1.41. The A / S of the red mud is about 1.19, and the N / S of the...

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Abstract

The invention discloses a preheating roasting desulfuration and rapid cooling technology for high-sulphur bauxite in suspended state. Firstly, high-sulphur bauxite is ground till the average particle diameter is below 300 micrometer, and the powder material is rapidly heated to 300-600 DEG C in a suspend preheating system by rising hot air stream; secondly, the preheated powder material enters a suspension furnace to be roasted in a suspended state, wherein the roasting temperature range is 450-750 DEG C; the roasted hot material is rapidly cooled in a cooling system by cold air, and the low-temperature roasting ore is obtained. The technology can perform suspension roasting desulfuration on high-sulphur bauxite with total sulphur content of 0.7-5.0% to obtain a raw material suitable for manufacturing alumina through the Bayer process, during dissolution of the roasting ore through the Bayer process, the dissolution rate of the alumina is higher than 95%; the method overcomes the deficiencies of a rotary kiln and a fluidized bed, the roasting time is short, the output per machine hour is high, the heat efficiency is high, the energy consumption is low, and the product activity is high.

Description

technical field [0001] The invention belongs to the technical field of resource utilization of high-sulfur bauxite, in particular to a high-sulfur bauxite suspended state preheating roasting desulfurization-rapid cooling process. Background technique [0002] my country's high-sulfur bauxite (S T >0.7%) the existing reserves are about 500 million tons, and the sulfur element is mainly pyrite (FeS 2 ) exists in the form of high-sulfur bauxite, which leads to the ineffective utilization of high-sulfur bauxite in the industrial production of alumina, because the sulfur in bauxite will be dissolved in the form of SO 3 2- , SO 4 2- , S 2- , S 2 o 3 2- The accumulation of these forms of sulfur, especially negative divalent sulfur, in the circulating mother liquor not only causes pollution of the sodium aluminate solution and affects the dissolution process; but also accelerates the corrosion of steel in the sodium aluminate solution. In addition, high-sulfur bauxite of...

Claims

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Application Information

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IPC IPC(8): C01F7/02
CPCY02P20/10
Inventor 陈延信徐德赵博酒少武吴锋
Owner XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY