Counter-current acid leaching process for copper azole treated wood waste

Abstract

This study explores the performance of a counter-current leaching process (CCLP) for copper extraction from copper azole treated wood waste for recycling of wood and copper. The leaching process uses three acid leaching steps with 0.1 M H2SO4 at 75degrees C and 15% slurry density followed by three rinses with water. Copper is recovered from the leachate using electrodeposition at 5 amperes (A) for 75 min. Ten counter-current remediation cycles were completed achieving > or = 94% copper extraction from the wood during the 10 cycles; 80-90% of the copper was recovered from the extract solution by electrodeposition. The counter-current leaching process reduced acid consumption by 86% and effluent discharge volume was 12 times lower compared with the same process without use of counter-current leaching. However, the reuse of leachates from one leaching step to another released dissolved organic carbon and caused its build-up in the early cycles.

Copper extraction and recovery from alkaline copper quaternary and copper azole treated wood using sulfuric acid leaching and ion exchange or electrodeposition

“…Cost of natural gas used was calculated for drying of the remediated wood chips down to 8% humidity. The analysis accounted for countercurrent water and sulfuric acid recirculation as described in Janin et al (2012c). The model was adapted for leachate treatment either by ion-exchange with Cu recovery as Cu-MEA solution for reuse in wood treatment or by electrolytic treatment with recovery as solid Cu.…”

“…An efficient acid leaching process to remove metals from treated wood has been patented in the last years (Janin et al, 2017). This process was initially developed for CCAtreated wood wastes (Coudert et al, 2014;Frighetto Ferrarini et al, 2016;Janin et al, 2009aJanin et al, , 2012a and was then applied to ACQ-and CA-treated wood waste (Coudert et al, 2013a,b;Janin et al, 2011Janin et al, , 2012c. Sulfuric acid is used to chemically extract the metals from treated wood and break the metal-wood bonds.…”

Uranium, Cesium, and Mercury Leaching and Recovery from Cemented Radioactive Wastes in Sulfuric Acid and Iodide Media

“…Counter-current leaching is a common method used to reduce the reagent consumption and to increase the solubilization of contaminants [28][29][30]. The process effluents are generated by a leaching step, a rinsing step or a leachate treatment step.…”