Outotec Oyj

Outokumpu Oyj

Aija Rytioja

Pekka Taskinen

Jens Nyberg

Maija-Leena Metsärinta

Heljä Peltola

Dag Berg

Helja Peltola

This invention relates to a method for removing mercury from dilute sulphuric acid. According to the method sulphuric acid solution is scrubbed with an aqueous solution containing thiosulphate, which precipitates the mercury present in the sulphuric acid solution either as mercury sulphide or, in a chlorine-containing environment, as a mercury sulphide-mercury chloride double salt. The quantity of thiosulphate to be fed is adjusted so that it precipitates the mercury in the sulphuric acid solution, but still does not form elemental sulphur.

Method for the removal of mercury from sulphuric acid with thiosulphate precipitation

This invention relates to a method for stabilizing a fluidized bed used in roasting by adjusting the oxygen content of the roasting gas in the bed. The fine-grained material for roasting is fed into the furnace above the fluidized bed and the roasting gas, which causes the fluidizing, is fed into the bottom of the furnace through a grate. In this method, the total amount of oxygen in the roasting gas to be fed and the average total oxygen requirement of the material to be roasted are calculated and the ratio between them regulated so that the oxygen coefficient in the bed is over 1.

Method for the stabilization of a fluidized bed in a roasting furnace

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Kokkola, Finland

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