METHODOLOGY FOR RECOVERY PRECIOUS METALS: GOLD, SILVER AND PLATINUM GROUP FROM ELECTRONIC WASTE
OSCAR JAIME RESTREPO B. firstname.lastname@example.org HONORIO OLIVEROS GÓMEZ email@example.com Instituto de Minerales - CIMEX. Universidad Nacional de Colombia. Sede Medellín.
ABSTRACT Colombia produces nine tons of electronic waste per year and there are approximately 60 tons accumulation generatedin the last nine years. This work aims to establish a general methodology in the laboratory to recover gold, silver and platinum group present in electronic waste, also explore other forms of recovery of metals contained in electronic waste. We selected seven types of electronic cards present in the computers, which have their parent desoldering electronic components. Initially, we characterizedthe components of the cards through X-ray diffraction and SEM, to identify the metal species and composition. Tests were conducted laboratory hydrometallurgical recovery of metals. This paper proposes a methodology for laboratory-scale work. KEYWORDS: Electronic wastes, leaching, electrowinning, electronic component, precious metals
1. INTRODUCTION Colombia produces nine tonnes of electronicwaste per year and build there in about 60 tons generated in the last 9 years , Computers, TVs, audio equipment, monitors, cell phones, remote controls, printers and operated toys battery, among others are part of this inventory, which mostly comes to landfills, because the lack of legislation to control the final destination of waste electrical and electronic equipment, and lack of efficienttechnologies to recover materials . Under these circumstances which have environmental implications, technological and economic recovery is essential metals present in the electronic cards of computers, by hydrometallurgical with subsequent base metal electrodeposition . Pyrometallurgical route is discarded by major implications for economic and environmental . Recovery From this perspective,the determination of the metal fraction and the relationship between the different metals, using the SEM characterization techniques - BSE and XRD is indispensable  It follows with electrolytic dissociation processes in the leaching and electrodeposition , and unit operations in the laboratory to carry out successfully these processes on a larger scale. Were randomly selected computertwenty-four postcards for nine types of cards have different functions in the computer, which, through the absorption desoldering technique, they broke the resistance (thermal, surface, photoresist, power), capacitors (ceramic, electrolytic), diodes (silicon, germanium, high frequency), transistor (NPN, PNP), processors, integrated (high, medium and low frequency), the RAM card and pin parallel portserial 2. CHARACTERIZATION 2.1 Materials • E-cards • Copper mesh and natural rosin
• Solder paste 2.2 Equipment and procedure Using a soldering iron absorption PACE brand SX - 90, dismantled the components of the motherboard, hard disk, network card, the switching power supply, video card, RAM card, the unit compact disk and floppy drive. Figure 2 shows the welding station and aspects of thedismantling of electronics.
Figure 1. PACE soldering station 90 SX
Components are grouped the 24 postcards in the categories: Integrated Surface, processors, resistors, diodes, RAM, transistors, capacitors and pin serial and parallel ports.
Figure 2. Ceramic and electrolytic capacitors
Then the metal surface is found present in every electronic component in order to select the pairs ofsamples for SEM and XRD characterization. Samples for SEM are replicated for DRX. Selected samples are necessary to characterize them through the analytical techniques listed. Procedure SEM - BSE: This technique was used to define the chemical composition of the metal fraction and the relationships between these species, present in electronic components. SEM images were taken in a JEOL JSM 5910...
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