Alkali metal silicate composition with sodium carbonate additive

• US 5,338,528 A
• Filed: 06/14/1993
• Issued: 08/16/1994
• Est. Priority Date: 11/14/1990
• Status: Expired due to Fees

• Current Assignee: Eka Nobel AB (Nouryon Coöperatief UA)
• Original Assignee: Eka Nobel AB (Nouryon Coöperatief UA)
• Inventors: Sorensson, Olle, Severinsson, Krister
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): HORTON, KENNETH
• Application Number:
  US08/075,927
• Time in Patent Office: 428 Days
• Field of Search: 423/332, 423/333, 423/334, 252/135
• US Class Current: 423/333
• CPC Class Codes: C01B 33/325 After-treatment, e.g. purification or stabilisation of solutions, granulation; Dissolution; Obtaining solid silicate, e.g. from a solution by spray-drying, flashing off water or adding a coagulant
• CPC Class Codes: C11D 3/08 Silicates

Abstract

The invention concerns a solid alkalimetal silicate having a molar ratio SiO₂ :M₂ O from about 1.5 to about 3, in which M is an alkalimetal and substantially consists of sodium and optionally potassium. The silicate contains from about 7 to about 20% by weight of sodium carbonate based on the dry material and has a water content from about 14 to about 22% by weight.

Further, the invention concerns a method of preparing the silicate above, use of the same and cleaning agent compositions containing such a silicate.

Claims

1. Solid alkali metal silicate having a molar ratio SiO₂ :

M₂ O from about 1.5 to about 3, in which M is sodium, the silicate also containing from about 7 to about 20% by weight of sodium carbonate based on the dry material and the water content being from about 14 to about 22% by weight based on the total weight.

2. The solid alkali metal silicate of claim 1 wherein M also consists of potassium.

3. Alkali metal silicate as claimed in claim 1, wherein the alkali metal silicate has a bulk density exceeding about 800 g/l.

4. A method of preparing a silicate according to claim 1, the method comprising the steps:

(a) drying an aqueous solution of an alkali metal silicate to a solid state having a water content from about 14 to about 22% by weight, the alkali metal silicate having a molar ratio SiO₂ ;

M₂ O from about 1.5 to about 3 in which M is sodium;

(b) adding sodium carbonate, potassium carbonate or both to the solution prior to the drying or to the dry material in an amount so that the product will contain from about 7 to about 20% by weight of sodium carbonate based on the dry material.

5. A method as claimed in claim 4, wherein one or more potassium compounds are added to the solution prior to the drying or to the dried material.

6. A method as claimed in claim 4, wherein all additions of sodium carbonate, potassium carbonate, potassium hydroxide and potassium silicate are performed prior to the drying.

8. Alkali metal silicate as claimed in claim 2, wherein the alkali metal silicate contains potassium up to about 5% by weight K₂ O based on the dry material.

9. Alkali metal silicate as claimed in claim 1, wherein it contains potassium in an amount of from about 1 to about 5% by weight K₂ O based on the dry material.

10. Alkali metal silicate as claimed in claim 1, wherein it contains potassium in an amount of from about 2 to about 4% by weight K₂ O based on the dry material.

11. A method as claimed in claim 5, wherein one or more potassium compounds are added in an amount of from about 1 to about 5% by weight K₂ O based on the dry material.

12. A method as claimed in claim 5, wherein one or more potassium compounds are added in an amount of from about 2 to about 4% by weight K₂ O based on the dry material.

7. A method as claimed in claimed 4, wherein the drying is performed in a spray dryer.