Plant-based coagulant of Theobroma cacao L. as a substitute for Mercury in Colombian gold beneficiation

Abstract

The use of mercury in gold mining adversely affects the ecosystems and has raised concerns, especially in specific areas of Colombia. An alternative to the use of mercury involves using the mucilage of plant species for gold separation. Here we present the use of mucilage extracted from Theobroma cacao L pod husks. The coagulant agent can be obtained by: (i) cutting and macerating cocoa pod husks to obtain the mucilage, (ii) mixing the mucilage with water, and (iii) thermally treating the mucilage until a coagulant is obtained. This research showed that the coagulant agent from cocoa pod husks waste can replace mercury use in artisanal small-scale gold mining in Colombia. Our coagulant agent collects impurities, leaving the gold completely free, with a recovery percentage of 95%. Consequently, we can eliminate the use of mercury from the gold beneficiation process and thereby reduce water, soil, and air contamination. Additionally, by using solid waste as a coagulant agent, this becomes a successful case of circular economy.