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Verhulst D.,Extractive Metallurgy and Energy Efficiency | Lakshmanan V.I.,Process Research ORTECH Inc.
TMS Annual Meeting | Year: 2011

Past, existing and developing processes are reviewed, with emphasis on base and precious metals as well as titanium dioxide.


Krishnadev M.,Laval University | Larouche M.,Laval University | Lakshmanan V.I.,Process Research ORTECH Inc. | Sridhar R.,Process Research ORTECH Inc.
Journal of Failure Analysis and Prevention | Year: 2010

Failure of an old rope from a stringing lattice transmission towers occurred in winter while the rope was being removed to make way for a new rope. Fracture took place around mid-span. At that time, ambient temperature was -22 °C. Wire rope was in service for nearly 50 years. We were given the mandate to determine the reasons for the fracture of the wire rope and also to suggest measures to prevent such failures from occurring. The study involved laboratory testing (mechanical and metallographic) of representative wire rope samples. The effect of low temperature (from room temperature to -40 °C) on the tensile behavior of wires and wire rope samples was evaluated. In addition, we designed an instrumented impact test to assess the effect of notches, low temperatures and dynamic loading on the fracture behavior; however, no standards were available for direct comparison. Optical metallography was used to judge the extent of corrosion and the nature of microstructure and the cleanliness of the steel. The fracture morphology of broken tensile and impact specimens was carried out using scanning electron microscopy to establish relations between test parameters and fracture modes. Results indicate that considerations have to be given to the occurrence of corrosion, notches, low temperatures, and dynamic loading conditions when replacing wire ropes and this may necessitate the replacement of wire rope earlier than the time dictated by the criterion of 10% loss in breaking strength. Results also indicate that impact testing is a better evaluator of the susceptibility of wire ropes to brittle fracture than tensile tests. © 2010 ASM International.


Sharifi E.,University of Toronto | Sharifi E.,Process Research ORTECH Inc. | Barati M.,University of Toronto
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2010

An experimental study was conducted to quantify the rate of direct reduced iron (DRI) decarburization in a steelmaking slag using the constant volume pressure increase technique. Experiments were conducted by dropping DRI pellets into molten slag at temperatures from 1773 K to 1873 K (1500 °C to 1600 °C). Subsequent experiments were carried out in which the DRI pellets were preheated while the slag temperature remained constant. The effect of the initial carbon content and the preheating temperature of the DRI on the reaction rate was investigated. The decarburization of DRI seems to comprise two stages, a reaction between the FeO and DRI followed by decarburization through the iron oxide of slag. Carbon has a significant effect on the kinetics of both stages, whereas the preheating temperature mainly influences the rate of decarburization between FeO and carbon inside the pellet. © The Minerals, Metals & Materials Society and ASM International 2010.


Chattopadhyay A.,Process Research ORTECH Inc. | Gorain B.K.,Barrick Gold Corporation
26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings | Year: 2012

Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex, ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.


Chattopadhyay A.,Process Research ORTECH Inc. | Gorain B.,Barrick Gold Corporation
IMPC 2014 - 27th International Mineral Processing Congress | Year: 2014

Many double refractory gold deposits are characterized by the dominance of "invisible gold" (submicroscopic gold) as solid solution or as colloidal-sized particles in different sulfides and other phases. These deposits are mainly composed of silicates and carbonates with moderate clay and mica content and with minor amount of sulfides and organic carbonaceous matters. The presence of highly preg-robbing and finely disseminated carbonaceous matter adversely affects gold recovery in leach circuits. Characterization of carbonaceous matters, commonly known as TCM and quantification of gold associated within these carbonaceous matters along with different sulfide and oxide phases is highly complex and challenging. Studies were initiated on various complex ore deposits and also on samples representing various process streams. This paper presents the development of a systematic approach to gold deportment studies using state-of-the-art mineralogy characterization techniques for quantification of invisible and visible metal contents in various species. The relevance of this mineralogy characterization to metallurgy will also be discussed in this paper.


Lakshmanan V.I.,Process Research ORTECH Inc. | Sridhar R.,Process Research ORTECH Inc. | Chen J.,Process Research ORTECH Inc. | Halim M.A.,Process Research ORTECH Inc.
Transactions of the Indian Institute of Metals | Year: 2016

Demand of nickel, titanium, aluminum and gold is consistently increasing in the world while the extractable ores of these metals are gradually depleting. Chloride-based processes have several advantages over the conventional hydrometallurgical and smelting processes including higher leachability of complex ores, stability of chloro-complexes and regeneration of leaching reagents. Considering these advantages of the chloride chemistry, innovative mixed-chloride process flowsheets have been developed for the recovery of these metals from low grade laterite, ilmenite, bauxite and refractory complex ores and concentrates. These processes also produce value added byproducts such as cobalt, vanadium and iron oxide. Advantages of addition of magnesium chloride to hydrochloric acid, leaching and separation reaction mechanisms, and developed flowsheets are also discussed. © 2015, The Indian Institute of Metals - IIM.


Lakshmanan V.I.,Process Research ORTECH Inc. | Sridhar R.,Process Research ORTECH Inc. | Roy R.,Process Research ORTECH Inc.
TMS Annual Meeting | Year: 2011

Base metals and PGMs are currently recovered from sulfide concentrates using pyrametallurgical processes. These processes suffer from several limitations such as being capital intensive, scaling problems, SO 2 emissions and long delay in value recognition. Alternative hydrometallurgical technologies have so far not been successful and currently total pressure oxidation and partial pressure oxidation hydrometallurgical technologies are being evaluated. Process Research ORTECH has developed a unique hydrometallurgical process to recover base metals and precious metals using mixed chloride technology. In a first stage leach, base metals are recovered and elemental sulfur is liberated from hydrogen sulfide formed during this leaching stage. During second stage leach, precious metals are recovered using proven separation technologies. Some of the advantages of the process are the recovery of elemental sulfur from sulfide sulfur, recycle of the chloride lixiviant thereby eliminating effluent treatment steps and use of excess energy from the Claus reactor for the pyrohydrolysis step.


Lakshmanan V.I.,Process Research ORTECH Inc. | Sridhar R.,Process Research ORTECH Inc. | Roy R.,Process Research ORTECH Inc.
TMS Annual Meeting | Year: 2011

TiO 2 is used in paints, plastics, rubber, paper, inks, textiles and other miscellaneous applications. The demand for the pigment grade TiO 2 is growing at 3.0%/year on average and this invites the development of innovative and cost effective processes. The current processes are not designed to recycle the reagents and thereby discharge the effluents into the environment, causing an environmental concern. During this study, synthesis of TiO 2 from an ilmenite concentrate was investigated using an innovative atmospheric mixed-chloride leach process. The solution purification was carried out using solvent extraction in two stages. In the first stage iron removal was carried out and in the second stage titanium was extracted. The strip solution obtained from the second stage solvent extraction contained the purified titanium and from this stream pigment grade TiO 2 was recovered. The barren solution was used for reagent recovery and the regenerated leach liquor was recycled.


Patent
Process Research ORTECH Inc. | Date: 2013-11-29

A process for leaching a value metal from a titaniferous ore material comprising the step of leaching the ore material at atmospheric pressure with a lixiviant comprising magnesium chloride and hydrochloric acid is disclosed. Iron and titanium are leached into solution. Iron in the ferric state may be separated from titanium in solution using extraction with alkyl ketone. More effective separation of titanium with lower contamination with iron is obtained.


Patent
Process Research ORTECH Inc. | Date: 2016-04-07

The present invention relates to storage batteries, also known as rechargeable batteries, using a chloride electrolyte, especially in which the electrolyte is a ternary chloroaluminate. In particular embodiments, the electrolyte is molten chloroaluminate and especially molten at a temperature of about 140 C. In another embodiment, the electrolyte is in a liquid state, especially at a temperature in the range of 27 C. to 110 C. The preferred electrodes are aluminum and graphite. The batteries have a variety of uses, particularly including storage of electricity for future use.

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