Recommendation for lateritic Ni-ore processing: garnierite mineralogical and geochemical approach

The objective of this study is to analyze the mineralogy and geochemistry of garnierite and its implication for Ni laterite processing. Mineralogical analysis using optical microscopic and X-ray diffraction (XRD) methods were performed, whereas chemical composition was obtained by X-ray fluorescence (XRF) method. Genetically, Ni in laterite ore is associated with SiO2 and MgO and is not accompanied by the elements of Co, Fe, Cr, Al, Mn, and Ca. In this study, Ni-laterite ore has Ni content of 2.1%, SiO2 25.42%, S/M ratio 3.7, and Fe/Ni ratio 15.5, meaning that it is more suitable to be processed by pyrometallurgical route. However, there are some characters that still have to go through treatment, namely reducing of Fe from 32.63% to 20%, increasing MgO, and reducing SiO2 by blending. Result of mineralogical analysis shows that the dominant mineral is quartz (44.8%) and talc (38.85%) with small amount of lizardite (16.35%). The high content of quartz and talc and the low in lizardite of the Ni-laterite ore in the study area indicated that it is recommended for pyrometallurgical processing which is also in accordance with its geochemical characteristics.

EFFECT OF 5 WT.% WPCB POWDER AS REDUCTANT ON INDONESIAN NICKELIFEROUS ORE PROCESSING

EFFECT OF 5 WT.% WPCB POWDER AS REDUCTANT ON INDONESIAN LIMONITICNICKEL ORE PROCESSING. Waste printed circuit boards (WPCB) are among the most valuable parts of electronic waste with one of the fastest-growing waste streams in the world. The purpose of this study is to investigate the possibility of WPCB powder as an alternative reducing agent for the carbothermic process in nickel lateritic ore processing. WPCB waste was mixed with nickel ore at 1100ÚC in inert atmosphere. In addition, a conventional reductant of coal is also utilized for comparison. Both reductant are varied in concentration of 5 wt% and 15 wt%. Based on thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTA) investigation, it is observed that there exists a difference between WPCB powder, nickeliferous ore powder, and the mixture in their decomposed levels. The decomposed gasses of WPCB produced by thermal degradation in the TGA instrument are mainly composed of reduction gas, which plays a critical role in reducing the nickeliferous ore. This study shows that WPCB powder performs comparably to sub-bituminous coal in the pyrometallurgical processing of nickel ore, which is proved by X-Ray Diffraction (XRD) test results that the carbothermic products consists of FeNi, magnetite, wustite and fayalite. It can be concluded than WPCB powder has potential to be utilize as an alternative reductant.

Fluorammonium method of titanium slag processing

Titanium dioxide is the most common titanium-containing product on the world market, and the demand for it is increasing. The global consumption of TiO2 is 7 – 7.5 million tons annually. Titanium dioxide is mainly obtained from ilmenite and rutile concentrates. The largest producers are China, USA, Germany, UK, Mexico, and Saudi Arabia. In addition to the natural resources of titan, there are man-made sources. This type of resource includes titanium-containing slags obtained as a result of pyrometallurgical processing of ores and concentrates containing titanium dioxide. These slags, in addition to titanium dioxide, contain silicon in the form of dioxide, silicates or aluminosilicates, whose chemical processing is difficult due to their high melting point (more than 2000 °C) and the chemical stability of these compounds in mineral acids (sulfuric, nitric, hydrochloric). Processing of such raw materials is carried out by “classical” chlorine and sulfuric acid methods. The use of fluorides in industry is realized in the production of aluminum, zirconium, uranium, beryllium, niobium, etc., which indicates the possibility of using fluoride methods for titanium slags processing. The article discusses a method for producing titanium dioxide based on the use of ammonium hydrodifluoride NH4HF2 , which has a high reactivity to a number of chemically resistant oxides (oxides of silicon, titanium, aluminum, etc.). The fluoroammonium method for processing titanium slag using NH4HF2 involves slag decomposition of in NH4HF2 melt followed by silicon admixture sublimation. Cleaning from iron, aluminum and other impurities is carried out using a solution of NH4HF2. Further precipitation of titanium with treatment of the precipitate by AlCl3 and ZnCl2 solutions followed by calcination allows to obtain a rutile modification of titanium dioxide.

Pyrometallurgical processing of high-titaniferous ores.

The future development of Ural mineral and raw materials base of steel industry is considerably stipulated by the development of deposits of titanium-magnetite ores, the reserves of which are accounted for near 77% of iron ores of Urals. It was shown, that the content of titanium dioxide as well as harmful impurities in the titanium-magnetite have the decisive meaning for selection of processing technology of them for extraction out of them vanadium and other useful components. Technological schemes of the titanium-magnetite enrichment and industrial methods of titanium-magnetite concentrates processing considered. Examples of titanium-magnetite processing by coke-BF and coke-less schemes given. The problems of blast furnace melting of titanium-magnetite ores highlighted. Main problems relate to formation of refractory compounds in a form of carbo-nitrides during reduction of titanium and infusible masses in blast furnace hearth. It was shown, that intensification if carbides precipitation is stipulated by increase of intensity of titanium reduction at increased temperatures of a heat products and requires the BF heat to be run at minimal acceptable temperature mode. Technological solutions, necessary to implement in blast furnace for iron ore raw materials with increased content of titanium processing were presented, including increase of basicity of slag from 1.2 to 1.25-1.30, increase of pressure at the blast furnace top from 1.8 to 2.2 atm, decrease of silicon content in hot metal from 0.1 to 0.05%, application of manganese-containing additives. It was noted, that theoretically the blast furnace melting of titanium-magnetite is possible at titanium dioxide content in slag up to 40% when application of the abovementioned technological solutions, silicon content in hot metal to 0.01% and very stable heat conditions of a blast furnace. The actuality of titanium and its pigmental dioxide production increase was noted. Possibilities of development of Medvedevskoje and Kopanskoje deposits of high-titaniferous ores in Chelyabinsk region with extraction not only iron and vanadium but also titanium considered.

Li-Distribution in Compounds of the Li2O-MgO-Al2O3-SiO2-CaO System—A First Survey

The recovery of critical elements in recycling processes of complex high-tech products is often limited when applying only mechanical separation methods. A possible route is the pyrometallurgical processing that allows transferring of important critical elements into an alloy melt. Chemical rather ignoble elements will report in slag or dust. Valuable ignoble elements such as lithium should be recovered out of that material stream. A novel approach to accomplish this is enrichment in engineered artificial minerals (EnAM). An application with a high potential for resource efficient solutions is the pyrometallurgical processing of Li ion batteries. Starting from comparatively simple slag compositions such as the Li-Al-Si-Ca-O system, the next level of complexity is reached when adding Mg, derived from slag builders or other sources. Every additional component will change the distribution of Li between the compounds generated in the slag. Investigations with powder X-Ray diffraction (PXRD) and electron probe microanalysis (EPMA) of solidified melt of the five-compound system Li2O-MgO-Al2O3- SiO2-CaO reveal that Li can occur in various compounds from beginning to the end of the crystallization. Among these compounds are Li1−x(Al1−xSix)O2, Li1−xMgy(Al)(Al3/2y+xSi2−x−3/2y)O6, solid solutions of Mg1−(3/2y)Al2+yO4/LiAl5O8 and Ca-alumosilicate (melilite). There are indications of segregation processes of Al-rich and Si(Ca)-rich melts. The experimental results were compared with solidification curves via thermodynamic calculations of the systems MgO-Al2O3 and Li2O-SiO2-Al2O3.

Chalcopyrite leaching in acid media: a review

In the modern practice of copper production, more and more attention is paid to the possibility of treating low-percentage sulfide ores that cannot be treated with conventional procedures (crushing, grinding, flotation). In addition to this, the processes of obtaining copper from complex sulfide concentrates, which cannot undergo pyrometallurgical processing, are increasingly being investigated. Extraction of copper from such raw materials is in most cases achieved by applying leaching procedures. Since chalcopyrite (CuFeS2) is by far the most abundant copper sulfide mineral, a large portion of the research is focused on studying the behavior of chalcopyrite in the leaching process, because processes of copper extraction from increasingly poor raw materials may be created using results of these studies. In addition, the main objective of this research is examining the kinetics and mechanism of chalcopyrite oxidation under the influence of various oxidants (O2, Fe3 +, H2O2, chlorate ions, etc.) and at the same time obtaining data necessary for the development of copper production process that could satisfy increasingly stringent technological, economic and environmental criteria. The paper presents the existing knowledge of the chalcopyrite leaching procedure and phenomena that accompany chalcopyrite oxidation in acidic sulfate and chloride solutions.

Review of the past, present, and future of the hydrometallurgical production of nickel and cobalt from lateritic ores

Laterite ores are becoming the most important global source of nickel and cobalt. Pyrometallurgical processing of the laterites is still a dominant technology, but the share of nickel and cobalt produced by the application of various hydrometallurgical technologies is increasing. Hydrometallurgy is a less energy-demanding process, resulting in lower operational costs and environmental impacts. This review covers past technologies for hydrometallurgical processing of nickel and cobalt (Caron), current technologies (high-pressure acid leaching, atmospheric leaching, heap leaching), developing technologies (Direct nickel, Neomet) as well as prospective biotechnologies (Ferredox process).