Shape and mass of sand, water, a high swellability in water ends of bentonite and a wasserloeslichen alkali metal salt is

摘要

A moulding-sand composition comprises sand and a binder being bentonite mixed with from 1/8 to 3 x its weight of an alkaline alkali metal humate. The humate may be sodium humate, and may be the product of the reaction of lignite having an alkali solubility of at least 75% dry weight with NaOH. The composition may have green compressive strength of at least 0.17 kg. cm.-2 The composition may contain 3-5% anthracite ("sea coal"), or up to 5% SiO2 flour, iron oxide, or finely powdered coal or charcoal. The binder content may be, e.g., 2-4.4% wt., and the amount of water may be, e.g., 2 to 2.6%. The composition may be prepared by dry-mulling the dry ingredients, adding the water, and mulling again.