High-temperature pretreatment by means of an alkaline aqueous solution of ores having an argillaceous gangue containing at least one usable element

摘要

A process for pretreatment at high temperature by means of an aqueous pretreatment solution, of crushed ores containing at least one usable metal element, whose gangue contains argillaceous compounds which, in the attack operation for making use of the ore, are capable of forming a stable plastic suspension in the presence of water, which makes it virtually impossible subsequently to separate the liquid and solid phases by virtue of its character being such that it cannot be subjected to filtration and/or settlement, which is characterized in that, to cause stabilization of the argillaceous gangue before the operation of subjecting the ore to attack and to produce easy separation of the liquid and solid phases after the attack operation, the ore, the granulometry of which is at most equal to the liberation sieve mesh size of the metal or metals to be put to use, and before being subjected to the attack operation for making use of the ore, is brought into contact with an aqueous pretreatment solution containing at least 2.10.sup.-5 g/l of OH. sup.- ions, then the medium formed is immediately raised to the minimum pretreatment temperature of at least 120 C. in a period of time of at most 30 minutes reckoned from the time at which the ore is brought into contact with the aqueous pretreatment solution.