Dissolution Tubular Reactors (DTR) by Resources Gold Technology
Tubular Reactors are used for the gold leaching of ores, flotation concentrates and refractory ores that require accelerated or enhanced cyanidation reaction kinetics. Tubular reactors operate at high pressure and temperature effecting gold cyanidation within the volume of a pipe. A dissolution tubular reactor operates continuously with reagents injected into the pipe at various points using spargers. In many gold leaching applications pipe reactors also use Hydrogen Peroxide (H2O2) and O2 to react with sulfides and other minerals helping liberate gold and enhance the leaching process within the tubular reactor.
4 Au + 8 NaCN + O2 + 2 H2O → 4 Na[Au(CN)2] + 4 NaOH
The tubular reactor is fed with gold ore slurry, flotation concentrate or refractory gold ore via a high pressure slurry pump. A heat exchanger is used to start and maintain the thermal reaction within the pipe reactor. H2O2 and O2 are added sequentially at specific points to enhance the cyanide leaching process. Reacted slurry is discharged continuously via the primary heat exchanger and a specially designed venturi aperture. The area reduction followed by expansion of cross sectional area at the discharge point creates a high operating pressure within the tubular reactor. Use of tubular reactors significantly enhances reaction kinetics and facilitates difficult or high grade gold extraction.
Degradation of the H2O2 results in the generation of additional O2 and H2O increasing the Elsner reaction gradient towards the right. In some cases the exothermic nature of the reactions generates heat which together with the high pressure creates conditions similar to an autoclave within the tubular reactor.
Dissolution tubular reactors have a relatively low capital cost compared to other chemical treatment routes for gold ores and concentrates and make highly effective use of available space. DTR’s are designed to accommodate the specific residence times required by the material they are treating as well as the reagent requirements of the chemical reactions taking place in the tubular reactor.