| 摘要 |
Moulding sand containing 100.0 parts by weight of silica sand, 1-5 parts by weight of hydrophilic binder, 0.3-2 parts by weight of coal dust and 2-4 parts by weight of water, characterised in that it contains an addition of 5-8 per cent by weight in relation to the quantity of silica sand of ascorbic acid production by-product containing: 40-50 per cent by weight of manganese oxide, 1-2 per cent by weight of sodium hydroxide, 48-59 per cent by weight of water, trace quantities of the order of 0.01 per cent by weight of organic matter.
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