Evaluation of the potential of cellulose-lignin mixture from sugarcane bagasse for gold extraction

• Grant number: 20/03517-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2020
• End date: August 31, 2022
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal Investigator: Pedro Vitoriano de Oliveira
• Grantee: Gabriel Ribeiro Bento
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The project aims to evaluate the potential of the cellulose-lignin mixture of sugarcane bagasse as an adsorbent material for the extraction of gold ions and gold-thiosulfate and gold-thiourea complexes, with ICP OES determinations, to be applied in gold recovery. The sugar cane bagasse will be ground in a knife mill and electronic mortar and pistil, sieved, washed with water, with HCl and dried in an oven. Considering that one of the procedures for gold leaching from printed circuit boards occurs by the formation of gold-thiosulfate or gold-thiourea complexes, studies for the extraction of these complexes will be investigated. Therefore, the conditions for the formation of gold-thiosulfate and gold-thiourea complexes will be evaluated, such as pH and binder concentrations. The adsorption will be done in batch or in columns filled with cellulose-lignin. Adsorption isotherms will be obtained under equilibrium conditions and adjusted to classic adsorption models (Langmuir, Frumkin, Freundlich) to obtain the maximum amount of adsorbed and constant affinity between free gold and cellulose-lignin complexes. The concentrations of free gold and the complexes, in solution before and after adsorption on the cellulose-lignin substrate, will be determined by ICP OES. As a preliminary study, it is intended to perform the gold leaching from material crushed from PCIs and into the resulting solution and apply the conditions of separation and concentration of gold from solution derived from leaching of PCIs. (AU)