Method of reducing scale in the bayer process

Patent metadata

Field	Value
Publication number	US-10066124-B2
Application number	US-201414578965-A
Country	US
Kind code	B2
Filing date	Dec 22, 2014
Priority date	Dec 24, 2013
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

Methods for reducing aluminosilicate containing scale in a Bayer process involving treating a Bayer process equipment surface with a scale inhibiting composition having high ionic strength prior to exposure to a Bayer process stream.

First claim

What is claimed is:

1. A method for reducing aluminosilicate containing scale in a Bayer process, comprising:
identifying a Bayer process equipment surface that is subject to scale formation during the Bayer process;
contacting the identified Bayer process equipment surface with an amount of a scale inhibiting composition effective to form a treated surface that is more resistant to scale formation upon subsequent contact with a Bayer process stream than an otherwise comparable untreated surface,
wherein the scale inhibiting composition comprises a liquor comprising an aqueous solution of one or more water-soluble salts having at least about 0.004 wt/wt % or more of total dissolved salts or a liquor having a pH of about 11.0 or greater, the scale inhibiting composition further comprising a silicon-containing compound,
wherein the silicon-containing compound is a polymer or a polymeric reaction product comprising a unit of Formula (I) and a unit of Formula (II)—

wherein
T 1 and E 1 are each independently a first optionally substituted hydrocarbyl radical comprising from about 2 to about 40 carbons;
Q 1 is H or a second optionally substituted hydrocarbyl radical comprising from about 1 to about 20 carbons;
A 1a and A 2a are each independently a direct bond or an organic connecting group comprising from about 1 to about 20 carbons;
R 1a is H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 6 -C 12 aryl, optionally substituted C 7 -C 20 aralkyl, optionally substituted C 2 -C 20 alkenyl, Group I metal ion, Group II metal ion, or NR 2a 4 , where each R 2a is independently selected from H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 6 -C 12 aryl, optionally substituted C 7 -C 20 aralkyl, and optionally substituted C 2 -C 20 alkenyl; and
contacting the treated surface with the Bayer process stream,
wherein Q 1 is chosen from butyl, 2-ethylhexyl, C 8-10 alkyl, phenyl, cresyl, nonylphenyl, cetyl, octenyl, and octadecyl.

2. A method for reducing aluminosilicate containing scale in a Bayer process, comprising:
identifying a Bayer process equipment surface that is subject to scale formation during the Bayer process;
contacting the identified Bayer process equipment surface with an amount of a scale inhibiting composition effective to form a treated surface that is more resistant to scale formation upon subsequent contact with a Bayer process stream than an otherwise comparable untreated surface;
wherein the scale inhibiting composition comprises a liquor comprising an aqueous solution of one or more water-soluble salts having at least about 0.004 wt/wt % or more of total dissolved salts or a liquor having a pH of about 11.0 or greater, the scale inhibiting composition further comprising a silicon-containing compound; and
contacting the treated surface with the Bayer process stream,
wherein the silicon-containing compound is a reaction product of at least a polyamine, a first nitrogen-reactive compound, and a second nitrogen-reactive compound,
wherein:
the first nitrogen-reactive compound comprises a —Si(OR 1b ) 3 group and a nitrogen-reactive group, where R 1b is H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 6 -C 12 aryl, optionally substituted C 7 -C 20 aralkyl, optionally substituted C 2 -C 20 alkenyl, Group I metal ion, Group II metal ion, or NR 2b 4 , each R 3b being independently selected from H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 6 -C 12 aryl, optionally substituted C 7 -C 20 aralkyl, and optionally substituted C 2 -C 20 alkenyl;
the second nitrogen-reactive compound comprises a nitrogen-reactive group and does not contain a Si(OR 1b ) 3 group.

3. The method of claim 2 wherein the reaction product has a weight average molecular weight of at least about 500.

4. The method of claim 2 wherein the first nitrogen-reactive compound is chosen from glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane and chloropropyltrimethoxysilane.

5. The method of claim 2 , wherein the second nitrogen-reactive compound is chosen from alkylhalides, glycidoxy ethers and alkyl epoxides.

6. A method for reducing aluminosilicate containing scale in a Bayer process, comprising:
identifying a Bayer process equipment surface that is subject to scale formation during the Bayer process;
contacting the identified Bayer process equipment surface with an amount of a scale inhibiting composition effective to form a treated surface that is more resistant to scale formation upon subsequent contact with a Bayer process stream than an otherwise comparable untreated surface;
wherein the scale inhibiting composition comprises a liquor comprising an aqueous solution of one or more water-soluble salts having at least about 0.004 wt/wt % or more of total dissolved salts or a liquor having a pH of about 11.0 or greater, the scale inhibiting composition further comprising a silicon-containing compound; and

contacting the treated surface with the Bayer process stream,
wherein the silicon-containing compound comprises:
a first component having a general formula X or XI—

wherein R 1g is independently CH 2 , or CH 2 —CH 2 ; and X 3 is NH, NH—R 1g —NH, or NH—R 1g —NH—R 1g —NH;
3-glycidoxypropyltrimethyloxysilane as a second component; and
2-ethylhexylglycidyl ether as a third component;
wherein synthesis of the compound proceeds by combining the first component with the 3-glycidoxypropyltrimethyloxysilane at a reactive hydrogen of the first component to form an intermediate, and the intermediate then reacted with the 2-ethylhexylglycidyl ether to form the silicon-containing compound.

7. A method for reducing aluminosilicate containing scale in a Bayer process, comprising:
identifying a Bayer process equipment surface that is subject to scale formation during the Bayer process;
contacting the identified Bayer process equipment surface with an amount of a scale inhibiting composition effective to form a treated surface that is more resistant to scale formation upon subsequent contact with a Bayer process stream than an otherwise comparable untreated surface;
wherein the scale inhibiting composition comprises a liquor comprising an aqueous solution of one or more water-soluble salts having at least about 0.004 wt/wt % or more of total dissolved salts or a liquor having a pH of about 11.0 or greater, the scale inhibiting composition further comprising a silicon-containing compound; and

contacting the treated surface with the Bayer process stream,
wherein the silicon-containing compound is a polymer having pendant thereto a group or end group according to Formula XII:

wherein v is an integer of either 1 or 2; v+w=3; R 1b is chosen from H, C 1 -C 12 alkyl, aryl, Na, K, Li, and NH 4 ; and J is chosen from H and a hydrocarbon group having a number of carbons within the range of 1 to 20 carbons.

8. A method for reducing aluminosilicate containing scale in a Bayer process, comprising:
identifying a Bayer process equipment surface that is subject to scale formation during the Bayer process;
contacting the identified Bayer process equipment surface with an amount of a scale inhibiting composition effective to form a treated surface that is more resistant to scale formation upon subsequent contact with a Bayer process stream than an other

Assignees

• Cytec Ind Inc
• Cytec Ind Inc

Inventors

• Cywar Douglas A
• Calbick Chester J
• Kula Frank
• Stigers Dannon
• Taylor Matthew

Classifications

• C02F5/12

  containing nitrogen (C02F5/14 takes precedence) · CPC title

• C09D183/14 Primary

  in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms (C09D183/10 takes precedence) · CPC title

• C23F14/02

  by chemical means · CPC title

• C02F5/10

  using organic substances · CPC title

• C02F2103/16

  from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes · CPC title