Process to prepare surface-modified mineral material, resulting products and uses thereof

Patent metadata

Field	Value
Publication number	US-9580605-B2
Application number	US-201113640325-A
Country	US
Kind code	B2
Filing date	Apr 7, 2011
Priority date	Apr 16, 2010
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

The present invention refers to a process to modify at least part of the surface of at least one mineral material, and to the use, as an additive in an aqueous suspension of mineral materials having a pH between 5 and 10, of at least one agent, wherein the additive allows for the formation of a low volume, high solids content filter or centrifuge cake on dewatering the suspension.

First claim

The invention claimed is:

1. A process for manufacturing a surface-modified mineral material in which at least part of the surface of a mineral material is modified, the process comprising the following steps:
(a) preparing an aqueous suspension of mineral material having a solids content of from 10 to 80% by weight, based on the weight of the suspension, and at a pH of 5 to 10, wherein the mineral matter comprises calcium carbonate or talc;
(b) contacting the aqueous suspension of mineral matter of step (a) with at least one agent so that at least part of the surface of the mineral matter is modified;
(c) obtaining a suspension of the surface-modified mineral material from step (b) having a pH which is less than 10 and which is greater than 7 if the isoelectric point of the mineral material provided in step (a) is greater than 7, or a pH that is greater than the isoelectric point of the mineral material provided in step (a) if the isoelectric point is 7 or lower; and
(d) subjecting the suspension of the surface-modified mineral material from step (c) to one or more of: (i) filtration on a filtration medium to form a filter cake of surface-modified mineral material, (ii) centrifugation to form a centrifuge cake of surface-modified mineral material, (iii) concentration by thermal or mechanical methods to form a concentrated surface-modified mineral material, and (iv) drying to form a dried surface-modified mineral material;
wherein the agent is:
(i) in the form of an aqueous solution or a stable aqueous colloid having a pH of less than 6;
(ii) formed by mixing, in an aqueous environment, at least one phosphonic acid-comprising compound with one or more metal cations or metal-comprising cationic compounds, wherein the metal is selected from the group consisting of aluminium, zirconium, zinc, cobalt, chrome, iron, copper, tin, titanium and mixtures thereof, and wherein the phosphonic acid-comprising compound and the metal cations or metal-comprising cationic compounds are dosed such that the molar ratio of phosphonate hydroxyl groups: metal cation or metal comprising cationic compound is from 10:1 to 2:1; and
(iii) added in step (b) in an amount corresponding to from 0.04 to 1 mg by dry weight of agent per m 2 of the total surface of the mineral material.

2. The process according to claim 1 , wherein the suspension of step (a) has a pH of 7 to 10.

3. The process according to claim 1 , wherein the suspension of step (a) has a pH of 8 to 9.

4. The process according to claim 1 , wherein the mineral material is talc.

5. The process according to claim 1 , wherein the mineral material comprises calcium carbonate and dolomite.

6. The process according to claim 1 , wherein the mineral material comprises surface-reacted calcium carbonate.

7. The process according to claim 1 , wherein the mineral material comprises calcium carbonate and one or more of dolomite, a Group IIA and/or IIIA element-comprising phyllosilicate, montmorillonite, talc, magnesite, magnesium-comprising chlorite, and kaolin clay.

8. The process according to claim 1 , wherein the mineral material is a calcium carbonate.

9. The process according to claim 1 , wherein the aqueous suspension of step (a) comprises less than 0.1% by weight, based on the weight of dry mineral material, of a polyacrylate-based dispersant.

10. The process according to claim 1 , wherein the mineral material provided in step (a) has a BET specific surface area of 5 to 150 m 2 /g.

11. The process according to claim 1 , wherein the mineral material provided in step (a) has a BET specific surface area of 5 to 60 m 2 /g.

12. The process according to claim 1 , wherein the mineral material provided in step (a) has a BET specific surface area of 10 to 50 m 2 /g.

13. The process according to claim 1 , wherein the mineral material provided in step (a) has a weight median diameter (d 50 ) of 0.2 to 5 μm.

14. The process according to claim 1 , wherein the mineral material provided in step (a) has a weight median diameter (d 50 ) of 0.5 to 2 μm.

15. The process according to claim 1 , wherein the suspension in step (a) has a solids content of 20 to 80% by weight, based on the weight of the suspension.

16. The process according to claim 1 , wherein the suspension in step (a) has a solids content of 40 to 75% by weight, based on the weight of the suspension.

17. The process according to claim 1 , wherein the suspension in step (a) has a solids content of 50 to 70% by weight, based on the weight of the suspension.

18. The process according to claim 1 , wherein the agent is dosed in step (b) in an amount corresponding to from 0.1 to 0.75 mg by dry weight of agent per m 2 of the total surface of the mineral material.

19. The process according to claim 1 , wherein the agent is dosed in step (b) in an amount corresponding to from 0.1 to 5%, by dry weight relative to the dry weight of mineral material.

20. The process according to claim 1 , wherein the agent is dosed in step (b) in an amount corresponding to from 0.15 to 0.75%, by dry weight relative to the dry weight of mineral material.

21. The process according to claim 1 , wherein the agent is dosed in step (b) in an amount corresponding to from 0.15 to 0.5%, by dry weight relative to the dry weight of mineral material.

22. The process according to claim 1 , wherein the agent is provided in the form of an aqueous solution having a pH of 0 to 5.

23. The process according to claim 1 , wherein the agent is provided in the form of an aqueous solution having a pH of between 0.5 to 4.5.

24. The process according to claim 1 , wherein the phosphonic acid-comprising compound is an alkyl diphosphonic acid.

25. The process according to claim 1 , wherein the phosphonic acid-comprising compound is 1-hydroxyethane 1,1-diphosphonic acid (HEDP).

26. The process according to claim 1 , wherein the phosphonic acid-comprising compound is a selected from the group consisting of methylene diphosphonic acid (MDP), hydroxymethylene diphosphonic acid (HMDP), hydroxycyclomethylene diphosphonic acid (HCMDP), 1-hydroxy-3-aminopropane-1,1-diphosphonic acid (APD), aminotri (methylenephosphonic acid) (ATMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP) and phosphonosuccinic acid (PSA).

27. The process according to claim 1 , wherein the metal of the metal cation or metal-comprising cationic compound is aluminium or zirconium.

28. The process according to claim 1 , wherein a base is added before and/or after the agent.

29. The process according to claim 28 , wherein the base is selected from the group consisting of sodium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium aluminate, a basic polyphosphate, a basic phosphonate, and any mixture thereof.

30. The process according to claim 28 , wherein the base is a basic polyphosphate or a basic phosphonate.

31. The process according to claim 28 , wherein the base is a potassium salt of pyrophosphate, an alkali compound of HEDP, or a sodium and/or potassium and/or lithium compound of HEDP.

32. The process according to claim 28 , wherein the base is added in an amount of greater than or equal to 0.1% by dry weight, relative to the dry weight of mineral material.

33. The process according to claim 28 , wherein the base is added in an amount of fr

Assignees

• Wimmer Guenter
• Schölkopf Joachim
• Weitzel Hans-Joachim
• Stauffer Fridolin
• Omya Int Ag

Inventors

• Wimmer Guenter
• Schölkopf Joachim
• Weitzel Hans-Joachim

Classifications

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C09C1/028

  Compounds containing only magnesium as metal · CPC title

• C09C1/022 Primary

  Treatment with inorganic compounds · CPC title

• C09C1/42 Primary

  Clays · CPC title

• C09C1/021

  Calcium carbonates · CPC title