EP0079672A1
Expired / Lapsed
EP
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Method of forming foundry cores and moulds
Assignee: British Cast Iron Research Association
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Filing: 1982-10-07
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Granted: —
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Expires: 2002-10-07
Abstract
Abstract A binder for a foundry mould or core comprises an alkali metal salt of a polyvalent organic acid or a polymerised monovalent organic acid, for example sodium polyacrylate, and an alkaline earth hydroxide such as calcium hydroxide, together with a suitable solvent. Up to 80% of the calcium hydroxide may be replaced by a polyvalent metal oxide or hydroxide. The mixture may include small proportions of other materials, such as aluminium sulphate. It is important that the pH of the organic acid salt solution before mixing with the alkaline earth hydroxide should not be too high and it should preferably be between 5 and 8, in particular between 5.7 and 6.6.
Inventors
- 👤 John Glyn Dr. Morley
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:17
CPC Classifications
C; C04; C04B; C04B28/00; C04B28/28; B; B22; B22C; B22C1/00; B22C1/16; B22C1/167; B22C1/20; B22C1/22; B22C1/2206; B22C1/222
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
58 words
A method of forming a foundry mould or core comprising adding to a body of sand or similar refractory particles a binder comprising an alkali metal salt of a polyvalent organic acid or of a polymerised monovalent organic acid, together with an alkaline earth hydroxide and a suitable solvent, and passi.ig an acid gas through the resulting body.
Claim 2
Independent Claim
58 words
A method of forming a foundry mould or core comprising adding to a body of sand or similar refractory particles a binder comprising an alkali metal salt of a polyvalent organic acid or of a polymerised monovalent organic acid, together with an alkaline earth hydroxide and a suitable solvent, and passi.ig an acid gas through the resulting body.
Claim 3
Dependent Claim
13 words
A method according to claim 1 in which the gas is carbon dioxide.
Claim 4
Dependent Claim
18 words
A method according to claim 1 or claim 2, in which the polymerised organic acid is polyacrylic acid.
Claim 5
Dependent Claim
13 words
A method according to claim 3, in which the salt is sodium polyacrylate.
Claim 6
Independent Claim
18 words
A method according to any one of claims 1 to 4 in which the hydroxide is calcium hydroxide.
Claim 7
Independent Claim
48 words
A method according to any one of claims 1 to 5 in which the binder is prepared as an aqueous solution before addition of the alkaline earth hydroxide, and in which the pH of this solution, before addition of the alkaline earth hydroxide, is between 5.7 and 6.6.
Claim 8
Independent Claim
48 words
A method according to any one of claims 1 to 6 in which in addition to the alkaline earth hydroxide there is present in the binder a poylvalent metal oxide or hydroxide to the extent (by weight) of 0 to 80% of the total weight of non-organic constituent.
Claim 9
Dependent Claim
31 words
A method according to claim 7 in which a salt of a polyvalent metal is present, to an extent up to 10% by weight of the polyvalent metal oxide or hydroxide.
Claim 10
Independent Claim
40 words
A method according to any one of claims 1 to 8 in which the total weight of alkaline earth hydroxide and (if present) metal oxide is between 25% and 400% of the weight of the salt of the organic acid.
Claim 11
Independent Claim
30 words
A method according to any of claims 1 to 9 in which the organic acid salt is added to the extent of between 0.2 and 6% of the total weight.
Claim 12
Dependent Claim
25 words
A method according to claim 10 in which the organic acid salt is added to the extent of 0.5 to 1.5% of the total weight.
Claim 13
Dependent Claim
16 words
A foundry mould or core formed by the method of any of claims 1 to 11
References Cited (Backward Citations)
DE2814357A1
Cited
DE2945653A1
Cited
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