Degradation-resistant scale inhibitors

Patent metadata

Field	Value
Publication number	US-2016108253-A1
Application number	US-201414578972-A
Country	US
Kind code	A1
Filing date	Dec 22, 2014
Priority date	Oct 21, 2014
Publication date	Apr 21, 2016
Grant date	—

Abstract

Methods for reducing aluminosilicate containing scale in an alumina recovery process involving treating an alumina recovery process equipment surface with a degradation-resistant scale inhibiting composition having high ionic strength prior to exposure to an alumina recovery process stream.

First claim

What is claimed is:

1 . A method of 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; and contacting the treated surface with the Bayer process stream; wherein the scale inhibiting composition comprises a liquor comprising an aqueous solution of one or more water-soluble salts having at least about 0.04% of total dissolved salts and a silicon-containing compound having one or more —Si(OR) n groups, wherein: n is an integer from 1 to 3, and R 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 1 4 ; where each R 1 is independently chosen 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, wherein the silicon-containing compound is resistant to degradation in alumina recovery process streams at process temperatures from about 100° C. to about 265° C.

2 . The method of claim 1 wherein n is 3.

3 . The method of claim 1 wherein the aqueous solution of one or more water-soluble salts is Bayer process liquor.

4 . The method of claim 3 wherein the Bayer process liquor is chosen from spent Bayer process liquor, evaporated Bayer process liquor or pregnant Bayer process liquor.

5 . The method of claim 1 wherein the aqueous solution of one or more water-soluble salts comprises at least 0.1 weight % of total dissolved salts.

6 . The method of claim 5 wherein the aqueous solution of water-soluble salts comprises at least 5.0% of total dissolved salts.

7 . The method of claim 1 wherein the silicon-containing compound is a polymer or a polymeric reaction product.

8 . The method of claim 1 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.

9 . The method of claim 8 , wherein the first nitrogen-reactive compound is chosen from ((chloromethyl)phenylethyl)-trimethoxysilane, (p-chloromethyl)phenyltrimethoxy-silane, chloromethyltriethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 7-bromoheptyltrimethoxysilane, 3-bromopropyltrimethoxysilane, 11-bromoundecyltrimethoxysilane, 3-iodopropyltrimethoxysilane, 3-(trimethoxysilypropyl)-2-bromo-2-methylpropionate, 2-(3,4-epoxycyclohexyl)ethyl-triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl-trimethoxysilane, 5,6-epoxyhexyltriethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxy-silane, and (isocyanatomethyl)trimethoxysilane.

10 . The method of claim 8 , wherein the second nitrogen-reactive compound is chosen from alkyl halides, alkyl sulfates and alkyl epoxides.

11 . The method of claim 10 , wherein the second nitrogen-reactive compound is chosen from dimethylsulfate, chlorooctane, chlorohexane, benzyl chloride, epichlorohydrin, and C 8-10 alkyl halide.

12 . The method of claim 9 , wherein the first nitrogen-reactive compound is chosen from (3-chloropropyl)trimethoxysilane and (5,6-epoxyhexyl)triethoxysilane.

13 . The method of claim 8 , wherein the reaction product has a weight average molecular weight of at least about 500.

14 . The method of claim 8 , wherein the silicon-containing compound is free of β-hydroxy ether groups.

15 . The method of claim 1 , wherein the silicon-containing compound is a reaction product of an amine-containing molecule and an amine-reactive molecule containing at least one amine-reactive group per molecule and at least one —Si(OR 5e ) n group per molecule, wherein R 5e is hydrogen, C 1 -C 12 alkyl, aryl, Na, K, Li, or NH 4 .

16 . The method of claim 15 , wherein the silicon-containing compound is free of β-hydroxy ether groups.

17 . The method of claim 1 , wherein the silicon containing compound is water soluble and polyethylenimine based.

18 . The method of claim 17 , wherein the silicon-containing compound is free of β-hydroxy ether groups.

19 . The method of claim 17 , wherein the silicon containing compound is made by functionalizing a polyethylenimine backbone with either or both of silane compounds III and IV, and optionally with either of hydrophobe compounds V and VI—

wherein:
Z 1 and Z 3 are each independently a hydrocarbon group having a number of carbons in the range of 1 to 20 carbons;
Z 2 is chosen from H, optionally substituted C 1 -C 20 alkyl, optionally substituted C 1 -C 6 aryl, optionally substituted C 7 -C 20 aralkyl, optionally substituted C 2 -C 20 alkenyl, Group I metal ion, Group II metal ion and NR 1 4 ; wherein each R 1 is independently chosen 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
X is F, Cl, Br or I.

20 . The method of claim 19 , wherein the silicon-containing compound is free of β-hydroxy ether groups.

21 . The method of claim 1 , wherein the silicon containing compound is a polymer or polymeric reaction product comprising a unit according to Formula VII and a unit according to Formula VIII—

wherein
A 3 and A 4 are each independently a first optionally substituted hydrocarbyl radical containing from about 2 to about 40 carbons;
Q 3 is a H or second optionally substituted hydrocarbyl radical containing from about 1 to about 20 carbons;
R 4 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 , wherein each R 2a is independently chosen 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;
E 4 is a hydrocarbon group having a number of carbons in a range of 1 to 20 carbons; and
J 4 is chosen from H and a hydrocarbon group having a number of carbons in the range of 1 to 20 carbons, wherein v and w are integers from 0 to 3 and v+w=3.

22 . Th

Assignees

• Cytec Ind Inc

Inventors

• Song Airong
• Stigers Dannon
• Bausch Cory

Classifications

• C09D5/1625 Primary

  organic · CPC title

• C01F7/47

  of aluminates, e.g. removal of compounds of Si, Fe, Ga or of organic compounds from Bayer process liquors · CPC title

• C01F7/064 Primary

  Apparatus for digestion, e.g. digestor vessels or heat exchangers · CPC title

• C23F14/02

  by chemical means · CPC title

• C08F30/08

  containing silicon · CPC title