CN1281504C - Process for removing silicon dioxide from Bayer process sodium aluminate solution - Google Patents
Process for removing silicon dioxide from Bayer process sodium aluminate solution Download PDFInfo
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- CN1281504C CN1281504C CN 02110045 CN02110045A CN1281504C CN 1281504 C CN1281504 C CN 1281504C CN 02110045 CN02110045 CN 02110045 CN 02110045 A CN02110045 A CN 02110045A CN 1281504 C CN1281504 C CN 1281504C
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Abstract
The present invention belongs to a preparation process of an inorganic intermediate body, particularly to a process for removing silicon dioxide from a Bayer process sodium aluminate solution. Ore slurry dissolved from diasporic bauxite is added with a sodium aluminate solution after the pre-desilication of lime for red mud separation, the mixture is filtered, and the concentration of suspended substances is from 0.0001 to 0.001 g/L; the solution is regulated by production mother liquor and washing liquor so as to comprise the six components of Na2O, Al2O3, CaO, CO2, SiO2 and H2O, wherein the concentration of Al2O3 is from 30 to 85 g/L, the concentration of Na2O[T] is from 80 to 90 g/L, the concentration of Na2Oc is from 2 to 20 g/L, the concentration of SiO2 is less than 1.0 g/L, caustic ratio is from 1.3 to 2.5, and the concentration of suspended substances is smaller than 0.001 g/L. Lime cream is added according to the quantity of SiO2 in raw liquor and 5 to 20 of the molecular ratio of CaO/SiO2, desilication is carried out at 80 to 100 DEG C, with 40 to 100 rpm and for 30 to 320 min. The present invention has the advantages of simple technology, high efficiency and no increase of three wastes to be discharged.
Description
Technical field
The invention belongs to abiology intermediate preparation method, is a kind of technology that removes silicon-dioxide from Bayer process sodium aluminate solution.
Background technology
Up to now, 95% of world's aluminum oxide output is still and utilizes classical Bayer process processing high-quality bauxite to produce.Its technology is roughly: bauxite, lime and alkali lye are made raw pulp according to a certain percentage; Hydrated alumina under high pressure (high temperature) condition in the stripping ore makes sodium aluminate (NaAlO
2) solution.At this moment, the SiO that exists with various mineral forms in the bauxite
2, under the NaOH effect, dissolving enters in the sodium aluminate solution.Look the concentration of lye height, SiO
2Content can reach 2～10g/L.
Dissolved SiO
2Form water glass (Na with the NaOH reaction
2SiO
3); Water glass is separated out the very little sodium white residue of solubleness with the sodium aluminate reaction and (is promptly contained sodium aluminosilicate of water, Na
2OAl
2O
31.7SiO
22H
2O).SiO in 25～250 ℃ of scopes of temperature
2At NaAlO
2In solubleness 0.1～0.5g/L the time, reach equilibrated silicon Index A ./Si (Al in the sodium aluminate solution
2O
3/ SiO
2, weight ratio) and can reach 400～600; Solution silicon Index A ./Si is than only about 300 in the actual industrial production.
Sintering process is produced aluminum oxide, SiO in the thick liquid of sodium aluminate grog stripping
2Content reaches 3.0～6.0g/L, and ./Si is than 20～30 for the silicon Index A; Tradition presses the cooking method desiliconization at 150～180 ℃, under solution oxide aluminum concentration 100～120g/L condition, and SiO
2Be reduced to 0.2～0.3g/L, the highest silicon Index A ./Si ratio that reaches is 350～400; Be further to improve the silicon index, take with once, the sodium white residue of secondary desiliconization separates, solution adds effective CaO and carries out three desiliconizations; The full alkali Na of sodium aluminate solution concentration
2O
T95～100g/L, Al
2O
385～95g/L; Caustic ratio 1.3～1.4; Add effective CaO 5～10g/L; The accurate solution of deep desilication, the A./Si ratio can reach 900～1100.
The sodium aluminate solution that the present invention adopts is the dissolution fluid that diaspore type bauxite adopts Bayer process high temperature, high density canalization dissolving-out process to produce, and ore pulp is taked to add the pre-desiliconization of lime normal pressure and handled.The accurate filtrate Al of sodium aluminate behind the separating red mud
2O
3140～170g/L; Na
2O
T(full alkali) 150～170g/L; Na
2O
c(Na
2CO
3, convert and be Na
2O) 12～25g/L; SiO
2Content 0.6～1.8g/L; Caustic ratio 1.5～1.7; Silicon Index A ./Si 85～130.Has high Na
2O
k, high Al
2O
3Concentration, high SiO
2Content, low silicon exponential characteristics.
The sodium aluminate solution of all above-mentioned Bayer process, sintering process preparation, unwanted component SiO
2Content, all reach and can not satisfy the requirement of producing high purity pseudoboehmite.
Summary of the invention
The purpose of this invention is to provide a kind of industrial sodium aluminate solution, surpass deep desilication, preparation can be satisfied the technology of the accurate solution of producing the high purity pseudoboehmite requirement.
Super deep desilication technology makes SiO in the accurate filtrate
2Content is reduced to＜0.00014g/L; Until leveling off to zero.Solution silicon Index A ./Si ratio reaches 10000～500000; Can be used as produce high purity pseudoboehmite (be Pseudobochmite, false boehmite, [AlOOH] nH
2O) raw material.
Technical scheme of the present invention is: develop a kind of technology that removes silicon-dioxide from Bayer process sodium aluminate solution, it is characterized in that comprising the steps:
1. the ore pulp of diaspore type bauxite stripping adds the pre-desiliconization of lime normal pressure and handles, and the sodium aluminate solution secondary filter behind the separating red mud, makes suspension content reach 0.0001～0.001g/L;
2. adjust with producing mother liquor and washing lotion that concentration of component is in the above-mentioned solution:
At Na
2O-Al
2O
3-CaO-CO
2-SiO
2-H
2In the hexa-atomic system of O, Al
2O
3Concentration 30～85g/L; Na
2O
T80～90g/L; Na
2O
c2～20g/L; SiO
2＜1.0g/L; Caustic ratio 1.3～2.5; Suspension content＜0.001g/L;
3. lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2Add solution under=5～20 conditions, in 80～100 ℃, stirring velocity 40～100rpm, reaction 30～320min carries out desilication reaction.
Described secondary filter is meant and adopts the filtration as filtration medium of fiber, synthon or the sintered microporous filter material of high molecular polymer; Described calcium oxide is the calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 80～98%; Described calcium oxide is a carbonate-free lime stone incinerating calcium oxide, effective CaO content 80～95%; Its desilication reaction terminal point controlled variable is: solid solution silicon-dioxide coefficient in the solid product, count 0.1～0.3 with mol; Dioxide-containing silica is reduced to＜0.00014g/L in the solution, until leveling off to zero; Silicon index aluminium/silicon is than 10000～500000; Its desilication reaction is finished rear slurry and is separated, the solid Ca-Al slag that desiliconization forms, and the alkali lye dilution with containing yellow soda ash 40～50g/L mixes; At 90～100 ℃ of stirring reaction 30～180min, decompose stripping Al
2O
3, make sodium carbonate causticization become NaOH, send the pre-desilication reaction groove of production raw pulp back to and apply mechanically.
The major technique feature of super deep desilication technology is: the composition in the stoste is at Na
2O-Al
2O
3-CaO-CO
2-SiO
2-H
2In the hexa-atomic system of O, be SiO
2Reaction forms the moisture sial DFP of calcium aluminosilicate hydrate type sosoloid, creates one and can make reaction carry out conversion zone completely.
Super deep desilication technology of the present invention comprises the solution secondary filter; The concentration adjustment adds additive and surpasses operations such as deep desilication.Carry out secondary filter before the solution desilicification, be meant and adopt the filtration of fiber, synthon or high molecular polymer filter material as filtration medium.For example, sintered microporous filter materials such as two fine filter membranes of canvas one smart filter cloth or synthon filter membrane or polyvinyl chloride, polyamide resin, polyacetal are as the filtration of filtration medium; Hold back all solid shape molecules, make suspension content reach 0.0001～0.001g/L; Accurate filter liquor concentration component makes main component content have medium alumina concentration through optimizing and revising; Medium caustic ratio; Low Na
2O
CConcentration; SiO
2Characteristics such as content＜1.0g/L, this accurate filtrate provide the stoste as super deep desilication.
Super deep desilication is the polynary system reaction between liquid-solid, liquid-liquid phase of finishing under normal pressure.Resultant solubleness is lower than moisture sodium silicoaluminate, in optimum Al
2O
3, Na
2CO
3, SiO
2Under the concentration, reaction can continue to SiO
2All solid solution is in calcium aluminosilicate hydrate sosoloid.SiO in the accurate filtrate
2Content is reduced to＜0.0014g/L; Until leveling off to zero.Solution silicon Index A ./Si ratio reaches 10000～500000; Can be used as the raw material of producing high purity pseudoboehmite.
Super deep desilication additive can adopt two kinds of the efficient oxidation calcium.One is chemical precipitation CaCO
3The incinerating active CaO, effective CaO content 80～98%; It two is CaCO
3The carbonate-free lime stone mechanized cement shaft kiln incinerating lime of content 96～100%, effective CaO content 80～95%.
Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=5～20 add solution, with steam heating temperature are increased to 80～90 ℃, keep stirring 40～60rpm, and reaction 30～60min carries out desilication reaction; Slurries press filtration after reaction is finished separates, the solid product that desiliconization forms, and mineral composition is with moisture ca aluminosilicate (3CaOAl
2O
30.15SiO
26H
2O) be main, have a small amount of CaCO
3And Ca (OH)
2, the SiO of moisture ca aluminosilicate solid solution
2Coefficient is between 0.14～0.29 mol; Ca-Al slag mixes with the alkali lye dilution that contains yellow soda ash 40～50g/L; At 90 ± 2 ℃ of stirring reaction 60min, decompose stripping Al
2O
3, finish sodium carbonate causticization and become NaOH, send the pre-desilication reaction groove of production raw pulp back to and apply mechanically.Improve the silicon index of pre-desiliconization as seed.
Desiliconization process is removed SiO
2Accurate solution, deliver to the gel operation, in alkaline mother liquor, finish the crystalline phase slaking, the pseudo-boehmite of generation carries out thorough washing, oven dry, is product.
The code name meaning of mentioning in the present patent application file is as follows:
Na
2O
TThe full alkali of-sodium aluminate solution concentration is meant Na
2O
C+ Na
2O
kBe that yellow soda ash+caustic soda conversion is sodium oxide; Silicon index aluminium/silicon ratio is meant and reaches equilibrated silicon index (Al in the sodium aluminate solution
2O
3/ SiO
2, weight ratio); Na
2O
c, be meant yellow soda ash, convert and be Na
2O.
Advantage of the present invention is: this technology grafts in aluminum oxide industry production, and technology is easy, and technology is reliable, does not increase three waste discharge, the economic benefit height, and production scale is big, is better than other acid-base neutralisation precipitator method.
Embodiment:
Embodiment one super deep desilication technology of the present invention comprises the solution secondary filter; The concentration adjustment adds additive and surpasses operations such as deep desilication.Carry out secondary filter before the solution desilicification, be meant and adopt the filtration of fiber, synthon or high molecular polymer filter material as filtration medium.For example, sintered microporous filter materials such as two fine filter membranes of canvas-smart filter cloth or synthon filter membrane or polyvinyl chloride, polyamide resin, polyacetal are as the filtration of filtration medium; Hold back all solid shape molecules, make suspension content reach 0.0001～0.001g/L; Accurate filter liquor concentration component makes main component content reach following index, as stoste: Al through optimizing and revising
2O
3Concentration 80～85g/L; Na
2O
T85～90g/L; Na
2O
C15～20g/L; SiO
20.9～1.0g/L; Caustic ratio 2.3～2.5; Suspension content＜0.001g/L.Described calcium oxide is the calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 90～98%; Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=20; 95～100 ℃ of temperature are stirred speed 95～100rpm, and reaction 300～320min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 500000; Slurries press filtration after reaction is finished separates, and Ca-Al slag dilutes with the alkali lye that contains yellow soda ash 40～50g/L, mixing; At 95 ± 2 ℃ of stirring reaction 120min, decompose stripping Al
2O
3, finish sodium carbonate causticization and become NaOH, send the pre-desilication reaction groove of production raw pulp back to and apply mechanically.Improve the silicon index of pre-desiliconization as seed.
Embodiment two stostes: Al
2O
3Concentration 30～35g/L; Na
2O
T80～85g/L; Na
2O
C2～5g/L; SiO
201～0.3g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 80～85%; Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=5; 80～90 ℃ of temperature are stirred speed 40～60rpm, and reaction 30～60min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 300000; All the other are with embodiment one.
Embodiment three stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T85～90g/L; Na
2O
C5～7g/L; SiO
20.5～0.8g/L; Caustic ratio 1.5～1.8; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 85～90%; Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=10; 90～95 ℃ of temperature are stirred speed 60～80rpm, and reaction 60～120min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 200000; All the other are with embodiment one.
Embodiment four stostes: Al
2O
3Concentration 50～55g/L; Na
2O
T85～88g/L; Na
2O
C7～9g/L; SiO
20.8～0.9g/L; Caustic ratio 1.8～2.0; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=15; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 120～140min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 100000; All the other are with embodiment one.
Embodiment Wuyuan liquid; Al
2O
3Concentration 70～75g/L; Na
2O
T85～90g/L; Na
2O
C15～16g/L; SiO
20.7～0.9g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=18; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 140～180min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 500000; All the other are with embodiment one.
Embodiment six stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T80～90g/L; Na
2O
C17～19g/L; SiO
20.6～0.7g/L; Caustic ratio 1.6～1.8; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=14; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 220～240min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 10000; All the other are with embodiment one.
Embodiment seven stostes: Al
2O
3Concentration 30～35g/L; Na
2O
T80～90g/L; Na
2O
C18～20g/L; SiO
20.5～0.6g/L; Caustic ratio 1.8～2.0; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=20; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 300～320min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 80000; All the other are with embodiment one.
Embodiment eight stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T80～90g/L; Na
2O
C17～19g/L; SiO
20.3～0.4g/L; Caustic ratio 1.6～1.8; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=13; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 220～240min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 90000; All the other are with embodiment one.
Embodiment nine stostes: Al
2O
3Concentration 80～85g/L; Na
2O
T80～90g/L; Na
2O
C2～5g/L; SiO
20.4～0.6g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.The calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 95～98%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=10; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 300～320min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 100000; All the other are with embodiment one.
Embodiment ten stostes: Al
2O
3Concentration 30～35g/L; Na
2O
T80～85g/L; Na
2O
C2～5g/L; SiO
20.1～0.3g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 90～95%; Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=5; 80～90 ℃ of temperature are stirred speed 40～60rpm, and reaction 30～60min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 300000; All the other are with embodiment one.
Embodiment 11 stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T85～90g/L; Na
2O
C5～7g/L; SiO
20.5～0.8g/L; Caustic ratio 1.5～1.8; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 80～85%; Lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=10; 90～95 ℃ of temperature are stirred speed 60～80rpm, and reaction 60～120min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 200000; All the other are with embodiment one.
Embodiment twelve source acupoint liquid: Al
2O
3Concentration 50～55g/L; Na
2O
T85～88g/L; Na
2O
C7～9g/L; SiO
20.8～0.9g/L; Caustic ratio 1.8～2.0; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 85～90%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=15; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 120～140min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 100000; All the other are with embodiment one.
Embodiment 13 stostes: Al
2O
3Concentration 70～75g/L; Na
2O
T85～90g/L; Na
2O
C15～16g/L; SiO
20.7～0.9g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 85～90%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=18; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 140～180min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 500000; All the other are with embodiment one.
Embodiment 14 stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T80～90g/L; Na
2O
C17～19g/L; SiO
20.6～0.7g/L; Caustic ratio 1.6～1.8; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 90～95%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=14; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 220～240min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 10000; All the other are with embodiment one.
Embodiment ten Wuyuan liquid: Al
2O
3Concentration 30～35g/L; Na
2O
T80～90g/L; Na
2O
C18～20g/L; SiO
20.5～0.6g/L; Caustic ratio 1.8～20; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 85～90%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=20; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 300～320min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 80000; All the other are with embodiment one.
Embodiment 16 stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T80～90g/L; Na
2O
C17～19g/L; SiO
20.3～0.4g/L; Caustic ratio 1.6～1.8; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 80～85%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=13; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 220～240min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 90000; All the other are with embodiment one.
Embodiment 17 stostes: Al
2O
3Concentration 80～85g/L; Na
2O
T80～90g/L; Na
2O
C2～5g/L; SiO
20.4～0.6g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 90～95%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=10; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 300～320min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 100000; All the other are with embodiment one.
Embodiment 18 stostes: Al
2O
3Concentration 50～55g/L; Na
2O
T85～88g/L; Na
2O
C7～9g/L; SiO
20.8～0.9g/L; Caustic ratio 1.8～2.0; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 80～85%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=15; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 120～140min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 100000; All the other are with embodiment one.
Embodiment 19 stostes: Al
2O
3Concentration 70～75g/L; Na
2O
T85～90g/L; Na
2O
C15～16g/L; SiO
20.7～0.9g/L; Caustic ratio 1.3～1.5; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 90～95%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=18; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 140～180min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 500000; All the other are with embodiment one.
Embodiment 20 stostes: Al
2O
3Concentration 60～65g/L; Na
2O
T80～90g/L; Na
2O
C17～19g/L; SiO
20.6～0.7g/L; Caustic ratio 1.6～1.8; Suspension content＜0.001g/L.Carbonate-free lime stone incinerating calcium oxide, effective CaO content 90～95%; By SiO in the stoste
2Content is by molecular ratio CaO/SiO
2=14; 95～100 ℃ of temperature are stirred speed 80～100rpm, and reaction 220～240min carries out desilication reaction; SiO in the accurate filtrate
2Content is reduced to＜0.00015g/L; Solution silicon Index A ./Si ratio reaches 10000; All the other are with embodiment one.
Claims (2)
1. technology that removes silicon-dioxide from Bayer process sodium aluminate solution is characterized in that:
(1) comprises the steps
1. with the ore pulp of diaspore type bauxite stripping, adding the pre-desiliconization of lime normal pressure handles, and the sodium aluminate solution behind the separating red mud, adopt fiber, synthon or the sintered microporous filter material of high molecular polymer as the filtration medium secondary filter, make suspension content reach 0.0001～0.001g/L;
2. adjust with producing mother liquor and washing lotion that concentration of component is in the above-mentioned solution:
At Na
2O-Al
2O
3-CaO-CO
2-SiO
2-H
2In the hexa-atomic system of O, Al
2O
3Concentration 30～85g/L; Na
2O
T80～90g/L; Na
2O
c2～20g/L; SiO
2＜1.0g/L; Caustic ratio 1.3～2.5; Suspension content＜0.001g/L;
3. lime slaking becomes milk of lime, by SiO in the stoste
2Content is by molecular ratio CaO/SiO
2Add solution under=5～20 conditions, in 80～100 ℃, stirring velocity 40～100rpm, reaction 30～320min carries out desilication reaction;
(2) described calcium oxide is the calcium oxide of chemical precipitation calcination of calcium carbonate, effective CaO content 80～98%;
(3) or described calcium oxide be carbonate-free lime stone incinerating calcium oxide, effective CaO content 80～95%
(4) described desilication reaction terminal point controlled variable is: solid solution silicon-dioxide coefficient in the solid product, count 0.1～0.3 with mol; Dioxide-containing silica is reduced to＜0.00014g/L in the solution, until leveling off to zero; Silicon index aluminium/silicon is than 10000～500000.
2. one kind according to the described technology that removes silicon-dioxide from Bayer process sodium aluminate solution of claim 1, it is characterized in that described desilication reaction finishes rear slurry and separate, the solid Ca-Al slag that desiliconization forms, the alkali lye dilution with containing yellow soda ash 40～50g/L mixes; At 90～100 ℃ of stirring reaction 30～180min, decompose stripping Al
2O
3, make sodium carbonate causticization become NaOH, send the pre-desilication reaction groove of production raw pulp back to and apply mechanically.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02110045 CN1281504C (en) | 2002-03-05 | 2002-03-05 | Process for removing silicon dioxide from Bayer process sodium aluminate solution |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02110045 CN1281504C (en) | 2002-03-05 | 2002-03-05 | Process for removing silicon dioxide from Bayer process sodium aluminate solution |
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| Publication Number | Publication Date |
|---|---|
| CN1377828A CN1377828A (en) | 2002-11-06 |
| CN1281504C true CN1281504C (en) | 2006-10-25 |
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|---|---|---|---|
| CN 02110045 Expired - Fee Related CN1281504C (en) | 2002-03-05 | 2002-03-05 | Process for removing silicon dioxide from Bayer process sodium aluminate solution |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109678185A (en) * | 2018-12-18 | 2019-04-26 | 杭州科创有色金属研究有限公司 | A kind of devices and methods therefor for crude liquid refining in alumina producing |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105129827A (en) * | 2015-08-27 | 2015-12-09 | 河南兴浩新材料科技股份有限公司 | Production method for pseudo-boehmite |
| CN106044817B (en) * | 2016-08-16 | 2017-05-24 | 青川天隆新材料开发有限责任公司 | Normal pressure fine-desilication method for preparation of aluminum oxide |
-
2002
- 2002-03-05 CN CN 02110045 patent/CN1281504C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109678185A (en) * | 2018-12-18 | 2019-04-26 | 杭州科创有色金属研究有限公司 | A kind of devices and methods therefor for crude liquid refining in alumina producing |
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|---|---|
| CN1377828A (en) | 2002-11-06 |
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