A mathematical model for isothermal heap and column leaching

Abstract

-Leaching occurs in metals recovery, in contaminated soil washing, and in many natural processes, such as fertilizer dissolution and rock weathering. This paper presents a model developed to simulate the transient evolution of the dissolved chemical species in the heap and column isothermal leaching processes. In this model, the solid bed is numerically divided into plane layers; the recovery of the chemical species, the enrichment of the pregnant leach solution, and the residual concentration of the leaching agent are calculated by interactions among the layers. The solution flow in the solid bed is assumed as unidirectional without dispersion, and the solid-fluid reaction is described by a diffusive control model that is integrated analytically for each time step. The data set used in the model include physical-chemical, geometrical, and operational variables, such as: leachable chemical species content, leaching agent flow rate and concentration, particles size distribution, solution residence time in the solid bed, and solid bed length, weight and irrigated area. The results for two case studies, namely, an industrial gold heap leaching and a pilot column copper acid leaching, showed that the model successful predict the general features of the process time evolution.

The Role of Mineral Assemblages in The Environmental Impact of Cu-Sulfide Deposits: A Case Study from Norway

“…They are placed in the field and subjected to meteoric waters, oxygen from the atmosphere, and changing temperature depending on the season. These tests can be conducted for several months to several years and are infrequently sampled for concentrations of dissolved metals and metalloids, sulfate, and changing pH and Eh parameters [33]. The tests can be accelerated by adding additional water [32].…”

Leaching of Coarse Caliche Ore. Experiment and Modelling

“…In general, the leaching consists of the dissolution of solids or part of them by adding a leaching solution, which is subsequently conducted to a separation process (De Andrade Lima, 2004). In the case of the production of iodine and nitrates from caliche, depending on the grade and granulometry of the ore, the leaching process takes place in vats or heaps.…”

Up-gradation of MoO3 and separation of copper, iron, zinc from roasted molybdenum ore by a leaching process

“…Nickel laterite ores kinetic studies were reported, recently (Sahu et al, 2011), and statistical examinations on gold-copper acid leaching studies were also reported (Mendes et al, 2003). Mathematical models developed on heap and column leaching studies developed and reported (de Andrade Lima 2004).…”