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AssigneeSocieta' Italiana Resine S.I.R. S.p.A.
InventorsLuigi Piccolo, Gabriele Bottai, Antonio Paolinelli, Angelo La Rovere
Estimating the term…
Soil modifiers comprising from 80 to 95% by weight of a mixture of ferric oxide and ferric sulphate in an oxide/sulphate weight ratio of from 0.2:1 to 2:1 are prepared by calcining at 500.degree.-600.degree. C in the presence of an oxidizing gas a material consisting essentially of ferrous sulphate with an average number of molecules of crystallization of from 1 to 5 obtained by partial dehydration of the waste materials, consisting essentially of ferrous sulphate heptahydrate, obtained in the manufacture of titanium dioxide from ilmenites or ilmenite slags by the sulphate process. These modifiers are particularly suitable for clay soils.
A method for preparing a compact soil modifier comprising from 80 to 95% by weight of a mixture of ferric oxide and ferric sulphate in an oxide/sulphate weight ratio of from 0.2:1 to 2:1, which comprises calcining at a temperature of from 500.degree. to 600.degree. C, in the presence of an oxidizing gas, a material comprising as a main component hydrated ferrous sulphate with an average number of molecules of crystallization of from 1 to 5, for a period sufficient to convert from 80 to 95% by weight of said hydrated sulphate into ferric oxide and ferric sulphate, said material being obtained by the partial dehydration of a waste material consisting essentially of ferrous sulphate heptahydrate obtained in the manufacture of titanium dioxide from ilmenites or ilmenite slags by the sulphate process.
Dependencies are inferred from the claim text.