Thiourea Supplier South Africa

What Is Thiourea?

Thiourea (CH₄N₂S, or (NH₂)₂CS) is an organosulfur compound structurally related to urea, where the oxygen is replaced by sulfur. In gold and silver metallurgy, thiourea is used as an alternative leach reagent to cyanide (NaCN). In acidic solution (pH 1–2) in the presence of an oxidant (typically ferric sulfate), thiourea forms the stable thiourea-gold complex [Au(Tu)₂]⁺ that allows gold to dissolve from the ore. Thiourea leaching operates at low pH (acidic conditions), unlike cyanidation (alkaline), making it particularly attractive for ore types where alkaline conditions are problematic, or where pre-treatment acidification has been applied.

Application to Refractory and Complex Ores

The main advantages of thiourea over cyanide leaching are its applicability to refractory gold ores with high arsenic, antimony, or telluride content where cyanide leaching is slow or inefficient; ores with high copper mineral content that consume excessive cyanide; and carbonaceous ores where preg-robbing (adsorption of gold cyanide complex onto carbonaceous material) limits cyanide recovery. Thiourea leaching of such ores in acidic conditions can achieve acceptable gold recovery with shorter leach times compared to cyanide. Thiourea also has significantly lower toxicity than cyanide, though it still requires responsible handling and disposal management.

Andre industrielle applikasjoner

Beyond gold metallurgy, thiourea is used in photographic fixing baths, as an accelerator in vulcanisation, in synthesis of pharmaceuticals and dyes, and as a corrosion inhibitor and metal surface brightener in copper and silver electroplating. Terracore Chemicals supplies thiourea in technical grade for mining and industrial applications.