ISSN 1062-7391, Journal of Mining Science, 2014, Vol. 50, No. 5, pp. 974–981. © Pleiades Publishing, Ltd., 2014.
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MINERAL DRESSING
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Conventional Flotation Techniques to Separate Metallic and Nonmetallic Fractions from Waste Printed Circuit Boards with Particles Nonconventional Size1 P. M. Gallegos-Acevedoa*, J. Espinoza-Cuadraa, and J. M. Olivera-Ponceb a Instituto de Minería, Universidad Tecnológica de la Mixteca, Carretera a Acatlima Km. 2.5, C. P. 69000, Huajuapan de León, Oaxaca, México *e-mail:
[email protected] b Industrial Engineering thesis, Universidad Tecnológica de la Mixteca, Carretera a Acatlima Km. 2.5, C. P. 69000, Huajuapan de León, Oaxaca, México
Received October 24, 2014
Abstract—This paper shows the results obtained by using a conventional Denver D12 flotation cell to separate the metal and a non-metallic material obtained from printed circuit boards (PCB). The bubble superficial surface rate (SB) and percentage of solids in feed was changed to evaluate the recovery of nonmetallic material in overflow product (concentrate) and the metal material in underflow (tailings). The solids content in feed is most influential parameter in nonmetallic material recovery. Finally, a flotation circuit is proposed as well as a flotation mechanism for this unconventional mix. Keywords: Froth flotation, printed circuit board (PCB), metal recovery, recycling, urban mining. DOI: 10.1134/S1062739114050172
INTRODUCTION
As a result of the revolution in information technology, the production of electrical and electronic equipment (EEE) has increased rapidly in the world [1]. Economic growth, technological innovation and market expansion of the EEE bring a significant increase in waste thereof, representing a new environmental challenge [2, 3]. The Waste Electrical and Electronic Equipment (WEEE) contain a variety of substances, organic and inorganic, whose composition depends on type and age of equipment manufacturing [4]. Since the late 90’s, it is considered that the WEEE are an important source of base materials such as precious and base metals, which have a high economic potential [5]. It is estimated that only in the European Union 8 million tons of WEEE are generated each year, with an annual growth rate of 5.3% [6] and 20 to 50 million metric tons in rest of the world [7]. The printed circuit boards (PCB) are the essential parts of electronic devices and contain metals in WEEE (Table 1), are particularly rich in copper and precious metals [8]. In general, PCB contain fiberglass reinforced resins (> 70%), copper (16%), iron (4%), iron and/or ferrite (3%), nickel (2%), silver (2%), gold (0.05%), palladium (0.01%) and others (bismuth, antimony, tantalum, etc.
