lixiviation à contre-courant

CONT: La lixiviation à contre-courant [...] améliore le rendement et diminue la consommation en réactifs [...]. Les minerais contiennent souvent des fractions plus ou moins facilement solubles. La solution de lixiviation doit contenir assez de réactifs pour dissoudre la fraction la plus difficilement soluble. [...] Il est évident que si l'on attaque la partie difficilement soluble par la solution neuve, et la partie facilement soluble par la solution provenant de cette attaque, le rendement de l'opération sera meilleur.

CONT: Countercurrent Leaching. [...] In such an operation fresh ore in a first stage is leached with partially depleted solution from a second stage -- this partially leaches the ore. The pulp is then filtered, the strong (pregnant) solution proceeding to metal recovery and the partially leached solids being mixed with strong leaching solution and placed in a second-stage unit. When leaching in the second stage is complete the liquids and solids are again separated by filtration, the liquid returned to mix with fresh ore in a succeeding cycle and the solids sent to waste or to such subsequent treatment as may be required.