A Chemical Investigation into the Role of Sorption Processes in Ore Genesis

摘要

Experimental evidence suggests that sorption processes in nature play a greater part in ore genesis than is generally believed. The results, as a whole, indicate that syngenetic accumulation of base metals by sorption is at least possible. In the case of uranium, the sorption process alone is able to explain the occurrence of some of the ore-grade uraniferous carbonaceous sediments. For other heavy-metal ores occurring in sedimentary rocks (possibly syngenetic), sorption processes are likely to have played a role in the early stages of ore development. However, the present-day structure of the orebodies and the texture of the contained minerals demonstrate that the sorption process was not the sole factor involved in the formation of the orebodies. Using solutions containing one ion-species only and sorbents composed of only one material, it was shown that the amount of metal ion sorbed from solution depended primarily on the nature of the sorbent and sorbate, the actual and relative concentrations of the two, the pH of the solution, and the addition of alkali or alkaline-earth metal ions or both to the same solution. Peat, as representative of the organic sorbents occurring in nature, was found to be by far the most efficient of all the sorbent materials used, and kaolinite the least. The results of the work using sorption columns corroborated the finding that copper and lead were preferentially sorbed by sorbents occurring in nature. This investigation also indicated that the sorptive capacity of the sorbents was approximately the same whether the sorbent was exposed to a small volume of a more concentrated metal-ion solution or a large recurrent supply of a more dilute solution.