Optimal parameters of the heap leaching of oxidized nickel ores by the box-wilson steep-ascent method. Part 1

We study the material composition of a ferromagnesian oxidized nickel ore of the Serov deposit. According to the results of chemical analysis, it was found that the studied ore is poor in the nickel content. Note that magnesium and iron are present in the ore as macroimpurities. The main nickel-containing minerals are lizardite and clinochlore; smaller amounts of nickel are contained in talc. To determine the optimal technological parameters of heap leaching and reveal their correlation dependences, we use the mathematical method of data processing, namely, the Box–Wilson steep ascent method. Based on the results of leaching, we compute the values of the efficiency criterion and the variance of the efficiency criterion and deduce a regression equation for the description of the process of leaching. The adequacy of the regression equation is established by using the Fisher criterion.

The results of mathematical processing of the experimental data show that the concentration of sulfuric acid in the solution, the pause between irrigations, and the specific consumption of the leaching solution exert a significant effect on the efficiency of leaching in the stage of nickel extraction from 0–30%.

On the basis of computed values of the efficiency criterion, we determine the values of variable parameters for the second stage of determination of the optimal conditions of leaching guaranteeing the efficient ore opening in the stage of nickel extraction up to 30%.