| 摘要 |
A moulding sand with an inorganic binder, such that the base of the former is quartz-, magnesite-, magnesite-chromite, or chromite-magnesite sand and which contains water and a binder containing ortho-phosphoric acid, wherein the binder is a reaction product of two components such that one of them is a powdered refractory material of which the grain size is up to 1 mm in a quantity in the range from 0.5 to 8 parts by weight relative to the base and which contains 50-98.5% by weight of MgO, 0.4-25% by weight of SiO2, 0.25-2.5% by weight of CaO, 0.25-13% by weight of iron oxides as Fe2O3, 0.1-9% by weight of Al2O3, inevitable contaminants being present at up to 0.5% by weight, and the other component is ortho-phosphoric acid at a concentration above 30% in a quantity in the range from 2.0 to 20 parts by weight relative to the base, the quantity of water being 0.25-1.5 parts by weight relative to the base.
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