International Journal of Advances in Science Engineering and Technology, ISSN(p): 2321 –8991, ISSN(e): 2321 –9009 Vol-6, Iss-3, Spl. Issue-2 Sep.-2018, http://iraj.in NOVEL CHEMICAL TREATMENT APPROACH AND CHARACTERIZATION OF GRAPHITE FROM INDUSTRIAL ALUMINUM WASTE

1OMAR ALJAROD, 2ABOUBAKR M. ABDULLAH

1Department of Chemistry, Qatar University, Doha 2713 Qatar 2Center for Advanced Materials, Qatar University, Doha 2713 Qatar E-mail: [email protected], [email protected]

Abstract - Thousands of tons of Spent Pot Lining (SPL) are produced annually by the primary aluminum producing industry. SPL is classified into two types, 1st and 2nd cut SPL waste. The 1st cut, which is the material under investigation in this study, is a contaminated graphite/ceramics material (50-60% of it is graphite) that is used in lining the electrolytic cell st where aluminum is produced by the reduction of molten Al2O3. 1 cut SPL is considered as a hazardous material as it contains contaminants such as fluorides, and small traces of cyanides. It also produces flammable gases when it comes in contact with water (i.e. , and ). This paper fully characterizes Qatalum’s 1st cut SPL that was de- lined from electrolytes cell, chemically treated this 1st cut SPL and extract the graphite component for use in some applications, in heavy metal ions removal from water. The functionalized graphite showed a high efficiency copper ions removal from aqueous solutions at different pH values with the efficiency at pH 7.

Keywords - Chemical treatment, Aluminum waste, Graphite extraction, Heavy metal removal, Wastewater treatment

I. INTRODUCTION Another composition of the 2nd cut lining is the insulation bricks that are installed under the Nowadays, the number of aluminum production refractory material to protect it from local high factories is growing rapidly to make the aluminum temperature and chemical attacks [16,17]. one of the most products used worldwide. Primary aluminum is mechanically produced by an energy demanding, two separate processes. The Bayer- process is the first-step reaction; where the raw material bauxite is refined having 30-60% alumina (Al2O3) to clear alumina[1, 2]. The second reaction is called the electrochemical reduction. In this process; the alumina is decomposed into its main element by an applied electrical current[3]. The Hall-Heroult process is an example of the aluminum smelting process that is used nowadays. Additionally, liquid aluminum is produced by the dissolving alumina (Al2O3) initially in cryolite (Na3AlF6). The process takes place in an electrolytic cell which is called the pot. A clarification of this pot is shown in Figure 1. The hall that contains the pots is usually located in a long row known as pot lines. The links between pots can be side by side or end by end. The basics of Fig.1Schematic drawing of the main features of an Hall- aluminum electrolysis are well described by Héroultaluminium reduction cell: (1) anode (prebaked); (2) numerous authors elsewhere [1, 4, 5]. electrolyte (bath); (3) Alumina point feeder, (3a) alumina The actual cathode is the reduced metal at hopper (3b) air cylinder, (3c) metering chamber, (3d) crust breaker; (4) aluminium pad; (5) anode beam (current supply); the bottom of the cell but the term “cathode” of the (6) anode yoke and stubs (iron); (7) anode rod (aluminium); (8) pot is granted for the carbonaceous pot lining [2,3]. anode clamp; (9) spent anode (butt); (10) alumina crust/ cover; Thepot lining can be classified mainly into 1st cut and (11) crust (side ledge); (12) cathode block; (13) current 2nd cut. The 1st cut is the cathode and is mainly collector bar (steel); (14) ramming paste; (15) refractory; (16) consisting of carbonaceous materials blocks with insulation; (17) steel shell; (18) sid