Abstract: The present invention provides a method of producing metal oxide(s) by sulfatizing a sulfide-free ore and/or concentrate comprising the steps of providing a sulfide-free ore and/or concentrate comprising sulfide-free mineral(s); and contacting the sulfide-free ore and/or concentrate with gaseous SO3 for sulfatizing the sulfide-free mineral(s) thereby forming metal sulfate(s) and metal oxide(s).

Abstract: Contaminated soils are treated in that an aqueous slurry of the soil is separated into a coarse fraction and a fine fraction, the fine fraction is subjected to flotation, the resulting froth is dewatered and then carried away as a pollutant concentrate, and the underflow from the flotation is dewatered and is then carried away as purified soil. An emulsified oily vegetable oil is used as a collector agent for the selective flotation or an emulsified light mineral oil is used as a collector agent for the selective flotation and a light mineral oil is stirred as a conditioning agent into the fine fraction before it is subjected to the selective flotation.

Abstract: To decontaminate contaminated soil, a layer of the soil is formed on a gas-permeable support in a pressure housing, steam at a temperature from 100.degree. to 190.degree. C. and under a pressure from 1 to 12 bars is fed to the pressure housing and is passed through the layer, the vapor leaving the layer is withdrawn from the pressure housing and condensed. The condensate is purified and the solids are carried away as decontaminated soil.