Deriving Value from Challenging Waste Materials: Recycling and Sustainability Joint Session: Deriving Value from Challenging Waste I
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

Wednesday 2:00 PM
March 1, 2017
Room: 14B
Location: San Diego Convention Ctr

Session Chair: Elsa Olivetti, MIT; Mingming Zhang, Arcelor Mittal Global R&D

2:00 PM  
Maximizing the Values of Steelmaking Slags: Naiyang Ma1; 1ArcelorMittal
    Along with steel production, various steelmaking slags are constantly gener-ated at considerably high rates. In general, steelmaking slags are not catego-rized into hazardous materials and do not cause any environmental issues. Therefore, recycling of steelmaking slags is often aimed at creating values by using the slags to replace high-cost raw materials. Chemical compositions and particle size distributions of slag products made from steelmaking slags will determine what raw materials the slag products can replace. Consequently, maximizing the values of steelmaking slags will require to produce slag prod-ucts with the highest values and to process the slags with the lowest costs. In this paper, several slag processing processes are assessed based on maximiza-tion of the values of the steelmaking slags.

2:20 PM  
Direct Preparation of Metal Doping Ni-Zn Ferrite from Zn-containing Electric Arc Furnace Dust by Calcination Method: Hui-gang Wang1; Min Guo1; Mei Zhang1; 1University of Science and Technology Beijing
    Metal doped Ni-Zn ferrite with spinel structure was directly synthesized from treated zinc-containing electric arc furnace dust (Zn-containing EAFD) by a solid state reaction method, realizing the transformation of solid waste to high value-added material. In order to prepare single phase spinel ferrite, a certain mass of NiCl2•6H2O was added to the treated Zn-containing EAFD before calcination. The effects of treated Zn-containing EAFD to NiCl2•6H2O mass ratio (RTZE/N, g/g) and calcination temperature on the preparation and magnetic properties of metal doped Ni-Zn ferrite were systematically investigated by X-ray diffraction, Raman spectroscopy and Physical Property Measurement System. It is shown that single-phase metal doped Ni-Zn ferrite, which exhibited excellent magnetic properties of higher saturation magnetization (Ms, 60.5 emu/g) and lower coercivity (Hc, 49.8 Oe), could be obtained when the calcination temperature was controlled at 1100 oC for 2 h with RTZE/N of 1:0.9.

2:40 PM  
Separation and Comprehensive Utilization of Valuable Elements in Ti-bearing Electric Arc Furnace Molten Slag: Yang Li1; 1Wuhan University of Science and Technology
    A novel route to comprehensive utilization of valuable elements such as Ti, Al, Si and Mg in Ti-bearing electric arc furnace molten slag (Ti-bearing EAF slag) was proposed in this work. The route can be expressed as a three steps process including alkali fusion, water leaching and acidolysis. Following these processes under the optimum conditions, the recovery ratios of TiO2, Al2O3, SiO2 and MgO were about 97.5%, 93.5%, 27.9% and 53.5%, respectively. Meanwhile, nanostructured TiO2, NaA zeolite and Mg(OH)2 fire retardant were synthesized simultaneously by using Ti-bearing EAF slag as raw materials. In addition, the photocatalytic activity of prepared nanostructured TiO2 and the adsorption property of obtained NaA zeolite were investigated. The results showed that the photodegradation efficiency of as-prepared TiO2 was 80% for Rhodamine B and the adsorption efficiency of NaA zeolite was 61% for Cu2+ under the optimum conditions.

3:00 PM  Invited
Recycling in the Real World -- Challenges and Functional Approaches for the Recycling of Complex Products and Hazardous Materials: Mark Kennedy1; C. Landaas2; P. Hellinckx2; 1Proval Partners, NTNU; 2Proval Partners
    Post-consumer wastes including: Waste Electronic and Electrical Equipment (WEEE), Printed Circuit Boards (PCBs), batteries, and fluorescent bulbs, contain valuable metals such as Precious Group Metals (PGMs), base metals, and Rare Earth Elements (REEE), capable of recovery by the metallurgical industry. The metallurgical industry itself produces a number of slags, dusts or wastes some of which are classified as hazardous, e.g. Electric Arc Furnace (EAF) dust, and Spent Pot Lining (SPL). Recycling of these diverse materials is hindered by factors including: (i) logistics (collection), (ii) economics (low value and complex processing), (iii) human psychology (NIMBY), (iii) lack of political will, (iv) technical complexity (low grade, heterogeneous, high standard deviation, varying physical characteristics), (iv) lack of proven processing technologies (first-of-a-kind or one-of-a-kind processes), etc. Current and best practices related to these issues will be explored and some examples given based on direct experience with WEEE, battery, EAF dust and SPL recycling.

3:30 PM Break

3:50 PM  
Recovery of Iron From Red Mud By Magnetic Roasting and Direct Reduction: Zhenhong Liao1; 1Changsha Research Institute of Mining and Metallurgy Co.,Ltd
    Red mud is a highly-alkalic solid slag generated in the alumina production industry with high grade of iron. On the basis of the detailed mineralogy study, low temperature reduction roasting-magnetic separation tests, desliming- low temperature reduction roasting - magnetic separation tests, the direct reduction magnetic separation tests were conducted respectively. A concentrate with TFe grade more than 60% was obtained by desliming- low temperature reduction roasting - magnetic separation test, the other concentrate with TFe grade 88.57%,TFe recovery 78.77% was obtained by direct reduction magnetic separation tests when 86.75% particle size is below 0.045mm.

4:10 PM  Cancelled
Recycling of Spent Pot Lining by Vacuum Distillation Process: Wang Yaowu1; 1 Northeastern University of China
    Spent potlining (SPL) was the main solid waste after electrolytic pot failure in aluminum electrolysis. The yield of SPL, which is composed of spent carbon cathode block and spent refractory materials containing fluorides, alkali metals and oxides, is about 20~50 kg per ton of aluminum. It is considered as hazardous material because it contains significant concentrations of toxic and leachable cyanides and fluorides. At present, no economical and satisfactory process for the treatment of SPL has been developed in the world. Land filling of SPL, which was adopted by most Chinese smelters, not only pollutes the environment, but also wastes secondary resources. The process of Vacuum Distillation Process(VDP) can separate alkali metals and aluminum electrolyte from SPL effectively. During the step of distillation, cryolite-based electrolyte and alkali metals are removed from SPL, distilled SPL can be recycled. This paper presents you some important data on VDP.