Deriving Value from Challenging Waste Materials: Recycling and Sustainability Joint Session: Deriving Value from Challenging Waste III
Sponsored by: TMS Extraction and Processing Division, TMS Light Metals Division, REWAS Organizing Committee, TMS: Energy Committee, TMS: Recycling and Environmental Technologies Committee
Program Organizers: John Howarter, Purdue University; Elsa Olivetti, Massachusetts Institute of Technology; Mingming Zhang, ArcelorMittal Global R&D; Randolph Kirchain, Massachusetts Institute of Technology; Henry Colorado, Universidad de Antioquia

Thursday 2:00 PM
March 2, 2017
Room: 14B
Location: San Diego Convention Ctr

Session Chair: Henry Colorado, Universidad de Antioquia; Elsa Olivetti, MIT; John Howarter, Purdue University

2:00 PM  
Kinetic Studies on the Recovery of Chromium from Stainless Steel Slags: Manuel Leuchtenmueller1; 1University of Leoben
    The production of stainless steel generates million tons of hazardous slag each year that contain various valuable elements, primarily chromium. Due to economic and environmental aspects, the recovery of the chromium represents an important task in order to increase the efficiency of raw material usage. A pyrometallurgical reduction process can recover the chromium from the slag phase into a ferroalloy. Furthermore, such a process enables the possibility to adjust the slags’ mechanical properties to achieve a marketable product for construction purposes. However, in order to operate the process in an economical feasible way, the treatment time must be as low as possible to decrease the costs of the process. The present work contains kinetic considerations with respect to the chromium recovery and evaluates the influence of various parameters like the process temperature.

2:20 PM  
Chromium Removal from Iron-rich Waste Generated during Processing Lateritic Nickel Ores: Hong Vu1; Petr Dvorak1; Tomas Frydl2; Jana Selucka1; Petra Starkova1; 1University of Chemistry and Technology Prague; 2Aero Vodochody Aerospace a.s.
    Waste, generated during high pressure leaching of lateritic nickel ores, contains about 50% of iron in form of magnetite but high chromium content (~3%) does not allow its extensive utilization as the raw material for pig iron production in blast furnace. The chromium removal from the waste was carried out by two methods: 1) oxidative alkali roasting with NaOH and/or Na2CO3, followed by water leaching and 2) oxidative leaching in KOH sub-molten salts solutions. The results show that about 90.1% of Cr was removed when the waste was roasted at 900oC for 3 hours with 33.1 wt.% of NaOH. The removal of 88.2 % of Cr was achieved if the waste was roasted at 900oC for 3 hours with 40 wt. % of Na2CO3. About 70 % of Cr was removed if the waste was leached at 190oC in 75 wt.% KOH for 8 hours.

2:40 PM  
Synthesis of Magnesium Oxide from Ferronickel Smelting Slag through Hydrochloric Acid Leaching-Precipitation and Calcination: Mohammad Mubarok1; Andik Yudiarto2; 1Institut Teknologi Bandung; 2PT. Antam, Tbk.
    At the present paper, synthesis of magnesia from ferronickel smelting slag is discussed. The first stage was extracting magnesium from the slag sample by leaching in HCl solution. Magnesium extraction of 97% was obtained from the leaching with HCl 8 molar, solid:liquid ratio 1:40 (gram/ml) and temperature 80oC after 24 hour. Solution purification was performed by adjusting solution’s pH at 95oC. At pH range of 3-4, iron precipitate was found as akagenite (FeO-OH). Nickel precipitations took place at pH range of 4-6, while dissolved Mg and Al started to precipitate in the forms of pyroaurite (Mg6Fe2CO3(OH)16∙4H2O) and hydrotalcite (Mg6Al2CO3(OH)16∙4H2O) at pH range of 8-9. High purity of brucite (Mg(OH)2) was obtained from Mg precipitation at pH range of 11-12, under stirring speed of 300 rpm and stirring time of 4 hour. High purity of MgO powder was obtained from the calcination of brucite at temperature of 1000oC for 240 minute.

3:00 PM  
Investigating the Use of Recycled Machining Waste as an Alternative Feedstock for Metal Additive Manufacturing: Parnian Kiani1; Haoyang He1; Jessica Bui1; Kaka Ma2; Julie Schoenung1; 1University of California, Irvine; 2Colorado State University
    Machining is an essential step in traditional manufacturing that increases the cost of production and material waste. A potential way to improve material utilization is to use machining chips as an alternative feedstock in metal based additive manufacturing processes such as Laser Engineered Net Shaping (LENS). The primary feedstock for LENS is gas atomized powder, which typically has a spherical morphology and controllable particle size. Machining chips, however, exhibit variable particle shapes and a wide particle size distribution. The gas atomization method represents significant energy consumption and cost, whereas using machining chips can decrease the cost, energy requirements and environment impact of this process. Mechanical milling can be applied to produce metal powder from machining chips. The feasibility of using pre-processed machining chips for LENS deposition has been investigated in this study. Environmental impact and economic evaluation have also been investigated by using life cycle assessment and cost modeling techniques.

3:20 PM Break

3:40 PM  Cancelled
Thermodynamic Analysis of the Recycling of Aircraft Al Alloys: Senlin Cui1; In-Ho Jung1; 1McGill University
    Significant amount of commercial aircrafts will be retired in 2020, and the recycling Al components in such aircrafts becomes important issue in aerospace and Al industry. In the present study, thermodynamic analyses for the various recycling technologies of Al alloys were performed based on the comprehensive and accurate thermodynamic database. The recycling technologies reviewed in this work include the vaporization process to reduce Zn, precipitation process to reduce Fe, Mn, Si, Ti, Zr, flux treatment for Al2O3 and MgO, etc. Several key issues and limitation of the recycling of the aircraft Al recycling will be discussed. All the thermodynamic calculations were performed using the FactSage FTlite database.

4:00 PM  
Lithium-ion Battery Recycling Through Secondary Aluminum Production: Reza Beheshti1; Ali Tabeshian1; Ragnhild Aune1; 1NTNU
    Today’s lithium-ion batteries (LiBs) are found in more than half of the hybrid-electric and plug-in hybrid vehicles on the marked, all-electric vehicles, and nearly all consumer electronics. As a result, recycling of LiBs will be a strategic necessity in the near future. In the present study, the conventional aluminium recycling process (secondary aluminium production) is suggested as a suitable process for treatment of LiBs. The overall idea is to recover aluminium, copper and lithium from a mixed waste stream of LiBs and aluminium scrap. A two-stage process, consisting of a preheating step and a melting step, were tested on smartphone batteries mixed with pure aluminium in a ratio 1:10 and the distribution of elements between the metal phase, the slag phase and the off-gas evaluated. The obtained results are compared and discussed based on the thermodynamic calculated by the use of the FactSage™ software version 7.