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Method of concentrating a bayer process liquor

A technology of Bayer process and liquid, applied in the field of concentrated Bayer process liquid

Inactive Publication Date: 2011-04-13
ALCOA OF AUSTRALIA LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, although the amount is significant, the low quality heat is conventionally understood to have limited utilization in the Bayer process

Method used

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  • Method of concentrating a bayer process liquor
  • Method of concentrating a bayer process liquor
  • Method of concentrating a bayer process liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0097] Example 1: Triple Effect Evaporation of Single Membrane Fraction and Spent Liquid

[0098] An example of the second embodiment is shown in figure 2 Among them, single-film stage and three-effect evaporation are included. In this example, calciner flue gas 12 (165°C, 41% w / w steam, 202 t / hr) from calciner 36 was passed through the membrane at a feed pressure of 2.55 bar and separated into dehydrated Stream 16 (171.5 t / hr) and steam rich stream 18 (30.5 t / hr). The dehydrated stream 16 contains goes to an expander or turbine (not shown) to recover some energy and then passes through a chimney 38; its dew point is 78°C. The 30.5 t / hr water vapor rich stream 18 is superheated to a temperature of 150°C by each available waste heat source (not shown) and sent to the first of 3 falling film evaporators 24, 40, 42 in series. The shell side of the heat exchanger section of a film evaporator. The evaporated water vapor stream 43 is compressed before being sent to the heat exc...

Embodiment 2

[0100] Example 2: Single membrane fraction, wet scrubbing with calciner flue gas, and triple effect evaporation of waste liquor

[0101] Another example of the second embodiment is shown in image 3 middle. It is basically similar to the situation described in Example 1, with the difference that the calciner flue gas 12 is cleaned by wet scrubbing 13 with water 10 before the compression system 50 (165°C, 41% w / w water vapor , 202t / hr), the compression system 50 is connected to the expander 52 for energy recovery. Wet scrubbing achieves a number of advantages including dedusting, further humidification of the membrane feed and cooling to feed to the compressor train. Stream 15 leaving wet scrubber 13 has a temperature of 85°C and a moisture content of 43.8 wt%. This stream is compressed to 2.55 bar using a compressor or booster 50 . Before feeding the membrane feed stream 17 into the membrane unit 14, the temperature of the membrane feed stream 17 is lowered by exchanging h...

Embodiment 3

[0106] Example 3: Two membrane fractions with wet scrubbing and triple effect evaporation

[0107] exist Figure 4In the illustrated example of embodiment, the calciner flue gas 12 (165°C, 41% w / w steam, 202 t / hr) is cleaned by wet scrubbing 13 with water 10 and passed through a compressor or booster 50 compression to 2.55 bar. The temperature of the membrane feed stream 17 was lowered to 180°C by exchanging heat with the water vapor rich stream 18 to raise its temperature to 161°C prior to feeding the membrane feed stream 17 into the membrane unit 14. The flow rate of membrane feed stream 17 is 211.7 t / h.

[0108] The steam rich stream 18 from the first membrane section 14 conveys 40.3 t / h of vapor (vapoursteam) into a header arrangement (not shown) which also receives 38.8 t / h of steam in the water vapor-enriched stream 19 from the second membrane section 34.

[0109] 171.4 t / h of dewatered stream 21 from the first membrane section was passed through water quench 55 whi...

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PUM

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Abstract

A method for concentrating spent Bayer process liquor, the method comprising the steps of: Passing at least a portion of a calciner flue gas to a separator to provide a dehydrated gas stream and a water vapour enriched stream Contacting the spent Bayer process liquor with the water vapour enriched stream; and Evaporating water from the spent Bayer process liquor, thereby concentrating the spent Bayer process liquor.

Description

field of invention [0001] The present invention relates to a method for concentrating Bayer process liquids. More specifically, the present invention relates to a method for concentrating Bayer process liquids using heat recovered from spent Bayer process gases. Background technique [0002] The Bayer process is widely used for the production of alumina from aluminum-containing ores such as bauxite. The process involves contacting an alumina-containing ore with a recycled caustic aluminate solution at elevated temperature in a process commonly referred to as digestion. In some cases, the bauxite was accompanied by a significant amount of organic material, partly responsible for the presence of a range of organic compounds in the resulting solution. [0003] After cooling the solution, aluminum hydroxide was added as seed crystals to cause additional aluminum hydroxide to precipitate therefrom. The precipitated aluminum hydroxide is separated from the caustic aluminate sol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D1/00C01F7/04C01F7/0606
CPCB01D53/268C01F7/0606B01D1/26B01D1/065
Inventor 迪安·伊利耶夫斯基彼得·斯图尔特·哈伊
Owner ALCOA OF AUSTRALIA LTD
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