Applications of Process Engineering Principles in Materials Processing, Energy and Environmental Technologies: An EPD Symposium in Honor of Professor Ramana G. Reddy: Hydrometallurgy
Sponsored by: TMS Extraction and Processing Division, TMS Light Metals Division, TMS: Energy Committee, TMS: Hydrometallurgy and Electrometallurgy Committee
Program Organizers: Shijie Wang, Rio Tinto Kennecott Utah Copper; Michael Free, University of Utah; Shafiq Alam, University of Saskatchewan; Mingming Zhang, Arcelor Mittal; Patrick Taylor, Colorado School of Mines
Tuesday 8:30 AM
February 28, 2017
Location: San Diego Convention Ctr
Session Chair: Shafiq Alam, University of Saskatchewan
P-CAC, a Unique Separation Technology for PGM Recovery: Shijie Wang1; Tracy Morris2; 1Rio Tinto Kennecott Utah Copper; 2Group Mexico Asarco Amarillo Copper Refinery
Preparative Continuous Annular Chromatography, or P-CAC, is an innovative separation technology, a unique approach to high-performance chromatography for the separation of PGM component mixtures from solutions. P-CAC consists of inlet/distribution head and outer/inner cylinders, and bottom plate/ fraction-collection as well. P-CAC has been applied in biotechnological and pharmaceutical downstream processing. It was the first time to explore an efficient PGM separation and recovery at the Copper Refinery. Laboratory trials with using a chloride solution for raffination for PGM are described and the tests results are presented in this paper.
The Physical Characteristics of Electrorefined Copper Starter Sheet Material: Daniel Majuste1; Paul Laforest2; Michael Moats2; 1Universidade Federal de Minas Gerais; 2Missouri S&T
The interaction of anode and electrolyte chemistry in copper electrorefining is complex. This is especially true with regard to the behavior of Group 15 elements (As, Sb, and Bi). To better understand this system, laboratory electrorefining experiments were conducted using commercial anodes with As/(Sb+Bi) molar ratios of 0.54 and 3.8 and an electrolyte collected from a commercial refinery. The effect of adding thiourea during plating was also examined. Twenty-one hour copper deposits were produced to simulate starter sheet production. The mechanical properties of the electrodeposited copper were measured using an industrially relevant empirical bend test and a one-point bend test developed by UFMG. To understand the differences in mechanical properties, the microstructure of deposits was examined using microscopy, x-ray diffraction, and electron backscatter diffraction.
Extraction of Copper from Sulfate-chloride Solutions by Using Hydroxyoxime Extractants: Maria Ruiz1; Ivan Gonzalez1; Javier Salgado1; Rafael Padilla1; 1University of Concepcion
In the mining companies in Chile, the use of chloride salts and/or sea water in the sulfuric acid leaching of copper minerals have been increasing steadily. This is the reason why the effect of chloride ions on the solvent extraction equilibria was investigated. Copper extraction isotherms were determined at 25 and 35 °C for aqueous solutions containing 6 g/l of Cu, 7 g/l of Fe, chloride ion concentrations of 0, 60, and 110 g/l, at a pH of 2.0. The organic phases were 20% v/v solutions of a ketoxime (LIX 84-IC) or a salicylaldoxime (LIX 860N-IC). It was determined that the presence of chloride in the aqueous solution had a negative effect on the extraction equilibria for both extractants. Therefore, when the chloride ion concentration increases, an efficient use of the extractant would become more difficult. An increase in temperature from 25 to 35 °C affected positively the extraction equilibria.
Hydrometallurgical Processes for the Recovery of Rare Earths, Nickel and Cobalt in Chloride Medium: M.A. Halim1; V. I. Lakshmanan1; R. Sridhar1; Darcy Tait1; 1Process Research Ortech Inc.
Rare earth elements (REE), nickel and cobalt find their use in developing strategic materials and their demand is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Process Research ORTECH Inc. (PRO) has developed innovative mixed chloride leaching processes for the recovery of REE from alumino-silicate ores, and nickel and cobalt from laterite ores. The addition of magnesium chloride in hydrochloric acid enhances the activity of the hydrogen ion by orders of magnitude, which permit rapid leaching rates at moderate temperature and atmospheric pressure, along with high metal recovery. Innovative solvent extraction process steps are used for separating these metals from pregnant leach solutions. PRO processes also produce value added by-product of high purity iron oxide and recycle chloride lixiviant to the leaching stage. This paper will describe the leaching and separation reaction mechanisms and potential process flowsheets.
9:50 AM Break
Leaching Characteristics of Sodium-Iron-Silicate Slags: Doug Schriner1; Patrick Taylor1; Joe Grogan2; 1Colorado School of Mines; 2Gopher Resource
This investigation was undertaken to characterize and evaluate the TCLP (Toxicity Characteristic Leaching Procedure) behavior of sodium-iron-silicate slags. The TCLP is the only regulatory leaching protocol used in the United States to determine whether metallurgical slag material can be disposed of as non-hazardous waste. Synthetic slags of several compositions were prepared from reagent powders and doped with various concentrations of impurities. The slags were heated to 1200°C then cooled at a controlled temperature profile. The TCLP leachate generated from the slag was analyzed and associations were made to the slag bulk chemistry, mineralogy, and cooling history. Through this the leachable phases and behaviors of the slag were determined.
A Cr6+-free Extraction of Chromium Oxide from Chromite Ores Using Carbothermic Reduction in the Presence of Alkali: Lidia Escudero Castejon1; Sergio Sanchez-Segado1; Stephen Parirenyatwa1; Yotamu Hara1; Animesh Jha1; 1University of Leeds
Oxidative alkali roasting of chromite is the state-of-the-art process for manufacturing chromium-containing chemicals, which involves dealing with serious environmental problems arising from handling Cr6+-containing wastes. In this article a new method for the extraction of Cr2O3 from chromite ores is explained, based on the carbothermic reduction of concentrates in the presence of alkali investigated in the temperature range of 950-1050oC. Under these conditions, the iron oxides present in the ore body are reduced to metallic iron and the resulting separation of chromium complex occurs by forming sodium chromite (NaCrO2). The reduced samples are magnetically separated for the recovery of an iron-rich fraction, and a non-magnetic fraction containing NaCrO2, MgO and other impurities. The further treatment of the non-magnetic fraction by leaching yields a Cr2O3-rich product of approximately 85% purity, with remaining alumina, alkali and magnesia. The main advantage of the process is that the oxidation of Cr3+ to Cr6+ is completely avoided; thereby decreasing the risk of land, air and water pollution.
METTOP-BRX Technology – Eliminating Concerns and Highlighting Potentials of the Concept of Tankhouse Optimization: Andreas Filzwieser1; Iris Filzwieser1; Stefan Wallner1; 1Mettop GmbH
Whenever thinking about increasing tankhouse performance two major aspects has to be considered, the technological feasibility as well as the economical impact. For meeting the requirement of an increased current density leading to an increased productivity, Mettop has developed the METTOP-BRX Technology, which allows the introduction of fresh electrolyte between each pair of anode and cathode. Although for many years a total of two industrial applications are in operation, the successful implementation of this technology that result in significant operational and economic advantages has not been fully accepted within the industry due to misunderstandings, incorrect interpretations and lack of awareness. It is intended with this paper to create a better understanding about the parallel flow technology by highlighting the industrial applications.
Gold and PGM Recoveries from Complex Feed Streams: Shijie Wang1; Jeff Lucht2; Jamie Baker3; Nickvinder Bhath3; 1Rio Tinto Kennecott Utah Copper; 2Johnson Matthey Inc.; 3Johnson Matthey Plc
Precious metals (PM) in copper anode slimes are traditionally recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of precious metals, including relatively inert metals such as gold and platinum group metals (PGM). In this paper, a new method to recover gold and PGM from complex and difficult feed streams is described. Using the suitable activate carbon and Advanced Ion Exchange (AIX) adsorbent which have high selectivity for gold and PGM over other metals. A series of incredible pilot test data plus the business case generated from the study results are presented in the paper.