Gold All-lime Cyanidation Project in Sarah Cumberland, Laos

Project Introduction

In this project, the only valuable element found in the ore is gold, with the content of 7.5g/t, and the content of copper, lead, zinc and arsenic is very low. The carbon content is 10.94%, but further analysis indicates that the carbon contained is mainly inorganic carbon, which will not affect the gold leaching process. In view of these raw ore properties, the Sarah Cumberland gold ore plant in Laos is designed with all-lime cyanide leaching process, a four-stage leaching and a five-stage absorption process.

Gold Leaching Process

When the grinding fineness -0.074mm content is more than 90%, the pulp concentration is 40%, the lime dosage is 3kg/t, the alkali pretreatment time is 2h, CNLITE gold environmental leaching reagent dosage is 600g/t, the leaching time is 24h, the gold leaching rate can reach 96.40%.Compared with cyanide leaching, the leaching rate is increased by 1.4% ,  the reagent dosage is reduced by 200g/t, and the leaching time is shortened by more than 12h. In addition, the leaching toxicity analysis of the leaching tailings of CNLITE gold environmental leaching reagent was carried out. Results showed that the leaching toxicity values of cyanide, copper, lead, zinc and arsenic in the tailings were within the national standard limits. It can be directly drained without detoxification treatment.

Process Index

For the Sarah Cumberland carbonate type ore in Laos, the leaching rate can be increased by 1.4%, the reagent consumption is reduced by 200g/t, and the leaching time is shortened by more than 12h compared to the sodium cyanide leaching process. A fair good leaching effect and remarkable economic benefits were achieved, with annual cost savings of 3.932 million Yuan and investment reduction of 4.15 million Yuan in preliminary project construction.