Home The Foundation bunge About Us Directory Project Support R & D R & D and Competitiveness Presentations Documents News and Mines Exploration Mining Agenda Extractive Metallurgy Other Topics Library Presentations Documents Title Memories Mining Engineering University of Chile Other memories of Title Links Contact
According to tests by experts, there is an increase in copper recovery by applying boric acid to the leaching solution. Electrowinning bunge tests were conducted with previously purified leach solution with a solvent extraction step, which was obtained with concentrations around 40 g / l copper.
In the first of these operations, ore leaching-type oxides is performed using a sulfuric acid solution with which irrigates stockpiles bunge for a given time, with a focus on maximizing the recovery of copper metal. Any improvement in this goal is relevant in the overall economic performance of the operation.
In this context, the company Quiborax SA, located in the region of Arica and Parinacota, bunge and producer of borates and boric acid, has done studies on the use of the latter as supplemental reagent for leaching copper oxide ore, obtaining bunge results quite encouraging.
In charge of these studies have been Marcelo Salgado, Process Control Engineer, Department of Engineering and Development Company, and Carlos Shuffer, Agrochemicals bunge Division Manager, who explains that thanks to tests using copper oxide ore grading in the range of 1.20% to 3.50% Cu soluble, results showed improvements in the recovery of copper, PLS solutions with higher concentrations of copper, and improvements in the efficiency of power usage in the electrowinning stage. bunge
"The minerals used were obtained from areas like Putre, Shrimp and Taltal species with variable contents of copper and cuprite, chrysocolla, and azurite atacamite with metallic bargain which include iron ore and non-metallic gangue composed of carbonates and silicates. All tests have been conducted on the premises of the Department of Engineering and Development Quiborax SA, starting with agitation leaching of ore milled using 78% under 200 mesh, "says Shuffer.
"The essence of what has been observed so far is the increased recovery. In parallel testing, we found average increases copper recovery in the range of 3% to 6% by adding boric acid to the leaching solution, results depend on the characteristics and ore grade, but the increase is always verified. "
What happens when you add boric acid leaching favoring copper mineralogical species that are refractory to acid leaching, bunge including probably some sulfur. Ie, it catalyzes the formation of copper sulphate, which is reflected in a decrease in the total copper content in the cuttings. As a result, the copper concentration in the rich solution (PLS) is increased at a rate of around 15% to 20% over the concentration of the PLS without boric acid addition.
The cost of innovation is associated with the initial purchase of boric acid, and then replenishing the amount lost by impregnation in the rubble that was dropped. According to the results of tests, we estimate consumption levels of the order of 82 kilos of boric acid per ton of fine copper recovered for a mineral that contains about 2% of soluble Cu. Quiborax SA has within its products boric acid in granular and powder (99.9% H 3 BO 3) serving any of them for these purposes.
Electrowinning bunge tests were conducted with previously purified leach solution with a solvent extraction step, which was obtained copper concentrations bunge around 40 g / l copper. Tests were conducted with middle and high current density, verifying an improvement in the efficiency of power usage by as much copper deposited from solutions containing boric acid on the order of 3 to 5%.
Boric acid present in the electrolyte is from the previous stages, but because it must be replaced due to losses electrolyte bunge solution, adjust the concentration of boric acid in the new electrolyte. The amount of boric acid to add will depend on the losses to be taken into the SX-EW stage of each particular transaction. On the quality of the cathode obtained purity is similar bunge to that obtained bunge in a similar operation without the use of boric acid.