Abstract
The aim is to develop the procedure for selecting the optimal consumption of blinding agents for cyanidation process of preg-robbing carbonaceous products, taking into account their effects on both natural carbonaceous components and artificial adsorbent. The problem lies in the fact that blinding agents, as a rule, simultaneously worsen the adsorption capacity of the synthetic sorbent, which requires precise control of their dosage. The experiments were carried out on a flotation concentrate with a cyanidable gold content of 31.75 g/t with varying kerosene consumption from 0 to 2 kg/t and activated carbon loading, which made it possible to determine the isotherms of gold sorption by coal and the solid phase of the pulp, as well as the amount of sorption activity. The proposed method allowed us to establish that the addition of kerosene 0.5-2.0 kg/t reduces the preg-robbing index of flotation concentrate from 88.4% to 52.2-79.8%, but an excess of the reagent impairs the efficiency of activated carbon. The key indicator is the ratio of the Freundlich isotherm constants for activated carbon (K1) and for the solid phase (K2), which reaches a maximum of 489 with a kerosene consumption of 1.0 kg/t. This indicator reflects the average gold distribution coefficient between the activated carbon and the solid phase. A further increase in the dosage of kerosene reduces K1/K2 due to the "poisoning" of activated carbon. The technique demonstrates that the optimal flow of the blinding agents corresponds to the peak of K1/K2, where the decline of preg-robbing index of solid phase is maximal, and the negative effect on activated carbon is minimal. The obtained results can be applied to other blinding agents, such as diesel fuel or surfactants. It is recommended to use this approach when selecting the consumption of blinding agents for both research and production purposes.
Keywords:
preg-robbing, carbonaceous matter, gold, blinding agents, cyanidation, adsorbent