Process and plant for producing metal oxide from metal compounds

A technology of metal compounds and oxides, applied in aluminum compounds, chemical instruments and methods, oxygen/ozone/oxide/hydroxide, etc., can solve problems such as difficulties in calcining devices, and achieve the effect of prolonging process conditions

Inactive Publication Date: 2010-10-06
OUTOKUMPU OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Difficulties often arise in calciners due to pre-combustion or post-combustion of supplied natural gas or other fuels

Method used

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  • Process and plant for producing metal oxide from metal compounds
  • Process and plant for producing metal oxide from metal compounds
  • Process and plant for producing metal oxide from metal compounds

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] Embodiment 1 (production alumina)

[0065] exist figure 1 In the device, about 213000 kg / h of alumina with a temperature of 65° C. and a surface moisture of 8.0 wt % is supplied through a screw conveyor 1 . One part of the alumina preheated in the first preheating zone A is introduced into the mixing chamber 14 and seven parts are introduced into the second preheating zone B. After passing through the second preheating section B, the temperature of the solid in the solid pipeline 19 is 341° C., and it is preheated to the extent that about 70% of bound water is removed. 9750Nm 3 The cold natural gas per hour is used as a fuel through a fuel pipeline 21 and introduced into a fixed annular fluidized bed 27 of a fluidized bed reactor 25 .

[0066] In such an application, the Froude number Fr of the particles in the fixed annular fluidized bed p About 0.17, the particle Froude number Fr in the mixing chamber p About 2.96, the particle Froude number Fr in the central tub...

Embodiment 2

[0072] Embodiment 2 (production alumina)

[0073] exist image 3 In the device, about 102000 kg / h aluminum hydroxide with a temperature of 65° C. and a surface moisture of 7.0 wt % is supplied through a screw conveyor 1 . One part of the aluminum hydroxide preheated in the first preheating section A is introduced into the mixing vessel 14, and eight parts are introduced into the second preheating section B. After passing through the second preheating section B, the temperature of the solid in the solid pipeline 19 is 343° C., and it is preheated to the extent that about 72% of bound water is removed. Will 5027Nm 3 Cold natural gas per hour is supplied as fuel to the fluidized bed reactor 25 through the lances 30 extending into the center pipe 26 and the mixing chamber 20 .

[0074] In such an application, the Froude number Fr of the particles in the fixed annular fluidized bed p About 0.34, the particle Froude number Fr in the mixing chamber p About 1.54, the particle Fro...

Embodiment 3

[0081] Embodiment 3 (preheating with annular fluidized bed heating section)

[0082] according to Figure 5 , for particularly efficient and gentle preheating, two of the first and second preheating sections A, B are replaced by annular fluidized bed heating sections 70, 71 with a chamber for a fixed annular fluidized bed 72 and a mixing chamber 73 Venturi preheater 3,4. In the first preheating step, the wet solids are surface dried and heated to a temperature of about 150°C. In the second preheating section B, the solid is then precalcined, in which about 70% of the bound water is removed, while further heating to about 350°C. In the first step, for example, 196t / h of wet hydrated alumina at a temperature of 65°C can be loaded into the fixed annular fluidized bed 72 of the annular fluidized bed heating section 70 of the first preheating section A, and heated by 5000Nm 3 / h of air fluidization. The fluidizing air is introduced into the fixed annular fluidized bed 72 throug...

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Abstract

The present invention relates to a process for producing metal oxide from metal com pounds, in particular metal hydroxide or metal carbonate, in which the metal compound is conveyed into a reactor (25) with fluidized bed, heated there to a temperature of 650 15 to 1150 DEG C by combustion of fuel, and metal oxide is generated, as well as to a corre-sponding plant. To improve the utilization of energy, it is proposed to introduce a first gas or gas mixture from below through a gas supply tube (26) into a mixing chamber (20) of the reactor (25), the gas supply tube (26) being at least partly surrounded by a stationary annular fluidized bed (27) which is fluidized by supplying fluidizing gas, and 20 to adjust the gas velocities of the first gas or gas mixture and of the fluidizing gas for the annular fluidized bed (27) such that the Particle-Froude numbers in the gas supply tube (26) lie between 1 and 100, in the annular fluidized bed (27) between 0.02 and 2, and in the mixing chamber (20) between 0.3 and 30.

Description

technical field [0001] The invention relates to a process for the production of metal oxides from metal compounds, especially metal hydroxides or metal carbonates, wherein the metal compounds are fed into a fluidized bed reactor in which the temperature to generate metal oxides, and the present invention also relates to corresponding devices. Background technique [0002] Known from EP0861208B1 is a method for the production of anhydrous alumina from aluminum hydroxide in a circulating fluidized bed, wherein first the aluminum hydroxide is dried, partially calcined in several preheating sections, and introduced under preheating conditions due to fuel Firing a fluidized bed reactor at a temperature in the range of 800-1000°C produces alumina. The exhaust gas from the fluidized bed reactor obtained during the combustion process is supplied to the preheating section for energy utilization. The metal oxides discharged from the reactor are subjected to multi-stage cooling while...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B13/32C01F7/44B01J8/38F23C10/12B01J8/00B01J8/18B01J8/24C01F7/445F23C10/14
CPCB01J8/1863B01J8/1827C01F7/445C01B13/324B01J8/1845B01J8/384F23C10/14F23C10/12B01J8/0025B01J8/1872Y02P20/129
Inventor M·赫尔施W·斯托克豪森M·斯特罗德
Owner OUTOKUMPU OY
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