CN103553371A - Method for preparing lime milk in alkaline process aluminium oxide production - Google Patents

Abstract

The invention relates to a method for preparing lime milk for bayer process two-stage calcium preparation in alkaline process aluminium oxide production. The method is characterized in that the lime milk is prepared by adopting bayer process primary-washing liquefaction ash or/and sintering process coarse liquefaction ash in a lime milk preparation process. The method for preparing the lime milk in the alkaline process aluminium oxide production can be used for reducing the dilution of system concentration and the steam consumption of evaporation. The adopted ashing solutions are from production solutions in the working procedures, and the solution amount is not increased, so that the bayer process through capacity is not influenced, and the separation and washing indexes of the bayer process are not influenced.

Description

A kind of milk of lime compound method of alkaline process alumina producing

Technical field

The present invention relates to a kind of two sections of methods of joining calcium milk of lime preparation used of bayer's process of alkaline process alumina producing.

Background technology

At present, in alkaline process aluminum oxide production process, the blending process of milk of lime is all to adopt water or square position mother liquor to carry out ashing.The problem that this milk of lime blending process exists is: when bayer's process adopts two sections, join calcium, second segment will add milk of lime, and the milk of lime of now water preparation adds in flow process, can cause the water yield of bringing flow process into increase, system concentration is caused and watered down, steam consumption for evaporation is raise; With mother liquor (ak:3.2 left and right) ashing meeting, cause soltion viscosity to increase, lime is difficult to dissolve, and ashing weak effect, also easily causes line clogging.More seriously, with the solution outside bayer's process stripping, red mud separation, washing procedure or water ground, enter this operation, can cause system liquid measure to increase, handling capacity reduces, but also can affect the control of liquid amount balance and postorder index.

Summary of the invention

Object of the present invention is exactly the deficiency existing for above-mentioned prior art, provides a kind of and can effectively reduce the watering down of system concentration, and reduces steam consumption for evaporation, and ashing is effective, and liquid measure maintains the milk of lime compound method of the alkaline process alumina producing of original balance.

The object of the invention is to be achieved through the following technical solutions.

A milk of lime compound method for alumina producing, is characterized in that milk of lime process for preparation adopts Bayer process primary wash liquor ashing or/and crude liquor used sinter method ashing, preparing lime milk.

The milk of lime compound method of a kind of alkaline process alumina producing of the present invention, adopt Bayer process primary wash liquor ashing or crude liquor used sinter method ashing, avoided bringing into the water yield the watering down system concentration of Production Flow Chart completely, reduced steam consumption for evaporation, ashing effect is better, adopts with Bayer process primary wash liquor and crude liquor used sinter method and mixes rear ashing, can reduce watering down system concentration, reduce steam consumption for evaporation, ashing effect is better.The ashing solution adopting all comes from the production solution of this operation, does not increase any liquid measure, makes bayer's process handling capacity unaffected, and bayer's process is separated, washing index is unaffected.

Embodiment

A milk of lime compound method for alumina producing, milk of lime process for preparation adopts Bayer process primary wash liquor ashing or/and crude liquor used sinter method ashing, preparing lime milk.

During operation, send lime slaking machine to carry out ashing the mixed solution of Bayer process primary wash liquor, crude liquor used sinter method or Bayer process primary wash liquor and crude liquor used sinter method, ashing liquid measure used is unrestricted, can, according to carrying required amount allocate arbitrarily, be mixed with the milk of lime that concentration meets production requirement.

Embodiment 1

Send lime slaking machine to mix with lime Bayer process primary wash liquor and carry out ashing, the composition the active calcium ion content of the milk of lime being mixed with reaches 180g/l, enters into high pressure digestion dilution trap, and its system caustic sodium concentration maintains 160g/l; Reduced steam consumption for evaporation.

Embodiment 2

Send lime slaking machine to mix with lime crude liquor used sinter method and carry out ashing, the composition the active calcium ion content of the milk of lime being mixed with reaches 160g/l, enters into high pressure digestion dilution trap, and its system caustic sodium concentration maintains 162g/l; Reduced steam consumption for evaporation.

Embodiment 3

The Bayer process primary wash liquor that is 1:1 by volume ratio and crude liquor used sinter method mixed solution, send lime slaking machine to carry out ashing, and the active calcium ion content reaches 170g/l, enters into high pressure digestion dilution trap, and its system caustic sodium concentration maintains 161g/l; Reduced steam consumption for evaporation.

Claims (1)

1. a milk of lime compound method for alkaline process alumina producing, is characterized in that milk of lime process for preparation adopts Bayer process primary wash liquor ashing or/and crude liquor used sinter method ashing, preparing lime milk.