| 摘要 |
1,137,703. Foundry mould compositions. FOSECO INTERNATIONAL Ltd. 16 Sept., 1966 [27 Sept., 1965], No. 40949/65. Heading C3N. Sand moulds or cores are formed by shaping and allowing to harden a mixture of: 100 parts by wt. of (a) sand or like particulate material, 1À2-2À5 parts of (b) aq. sodium silicate, and 0À2-1À0 parts of (c) CaSO 4 ; (b) may have SiO 2 /Na 2 O ratio of 2-3À3, with 35-55% solids content; (c) may be anhydrite, gypsum, or plaster of Paris. Also present may be 50- 300% by wt. based on CaSO 4 of (d) a colloid, polymer, or carbohydrate which retards the reaction between (b) and (c); (d) may be a gum, a protein, glucose, dextrose, or sucrose. An auxiliary hardener, e.g. calcium metasilicate or ferrosilicon, may also be present; (b) and (c) react to form calcium silicate.
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