Synergy of pyrohydrolysis with metals extraction from oxide ores.

Pilot-plant tests were carried out on the extraction of Co and Cu from a Congolese ore and Ni from a Polish laterite ore. The metal is extracted from small particles of the ores which are suspended in aqueous-phase droplets and dispersed in an atmosphere of hot fumes from the pyrohydrolysis of chloride solutions. The experiments were carried out in a tubular 3-phase reactor equipped with two slotted shelves which created a moving barrier for the upwardly transported hot fumes generated by burning gaseous methane in air enriched with gaseous HCl. The rates of metal extraction were significantly higher than for standard leaching processes. The duration of gas/liquid/solid contact at temperatures decreasing from 110 to 70 degrees C was no longer than 2 to 4 minutes, which was sufficient to extract 83-91% of the metals. A simplified flow-sheet is presented for the process and the potential energy savings in combining pyrohydrolysis with direct extraction rather than cool acid leaching are discussed.
Pilot-plant tests were carried out on the extraction of Co and Cu from a Congolese ore and Ni from a Polish laterite ore. The metal is extracted from small particles of the ores which are suspended in aqueous-phase droplets and dispersed in an atmosphere of hot fumes from the pyrohydrolysis of chloride solutions. The experiments were carried out in a tubular 3-phase reactor equipped with two slotted shelves which created a moving barrier for the upwardly transported hot fumes generated by burning gaseous methane in air enriched with gaseous HCl. The rates of metal extraction were significantly higher than for standard leaching processes. The duration of gas/liquid/solid contact at temperatures decreasing from 110 to 70 degrees C was no longer than 2 to 4 minutes, which was sufficient to extract 83-91% of the metals. A simplified flow-sheet is presented for the process and the potential energy savings in combining pyrohydrolysis with direct extraction rather than cool acid leaching are discussed.