Method for the concentration of spent acid
AssigneeOutokumpu Oyj
InventorsAarno Kalliokoski, Pauli Kuisma
Life of this patent
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Abstract
The invention relates to a method for the concentration of the spent acid produced in connection with the scrubbing smelter or roaster gas. The hot gas produced is scrubbed first by dry and then by wet separation, and the scrubbed gas is conducted to the manufacture of a sulfurous end product. The spent acid formed is dilute, and its sulfuric acid content is increased by making use of the thermal capacity of the actual hot gas, which comes from dry separation. Thus, by making use of the thermal capacity of the gas created in the process, it is possible to replace, at least partly, the use of evaporators.
Claims10
A method for the concentration of spent acid in connection with the scrubbing of gas formed in smelting or roasting processes of sulfidic ores or concentrates, the method comprising scrubbing the hot gas first by dry separation in a waste heat boiler and electrostatic precipitator and then by wet separation, in which sulfur trioxide of the gas is washed as spent acid and the scrubbed gas is conducted to final product manufacture, concentrating the spent acid by making use of the thermal capacity of the hot gas coming from the dry separation by conducting said gas to countercurrent contact with dilute spent acid and so at least partly replacing use of evaporators.
Dependencies are inferred from the claim text.