Pyrometallurgy

High-titanium slag can be oxidised by exposure to oxygen or water vapour, since the slag contains trivalent titanium and divalent iron; such oxidation is used in slag upgrading processes. The presence of water vapour may increase the rate of oxidation. To test this, samples of crushed high-titanium slag were oxidised in various mixtures of oxygen, argon, and water vapour, in a fluidised bed, at 800°C, for up to 2 h. The presence of water vapour did increase the degree of oxidation, without changing the nature of the reaction products, which were rutile, pseudobrookite with increased iron content, and some anatase.

Copper smelting slag is a solution of molten oxides created during the copper smelting and refining process, and about 1.5 million tons of copper slag are generated annually in Korea. The oxides in copper smelting slag include ferrous (FeO), ferric oxide (Fe 2 O 3), silica (SiO 2 from flux), alumina (AI 2 O 3), calcia (CaO) and magnesia (MgO). The main oxides in copper slag, which are iron oxide and silica, exist in the form of fayalite (2FeO·SiO 2). Since copper smelting slag contains high content of iron, and copper and zinc, common applications of copper smelting slag can be used in value-added products such as abrasive tools, roofing granules, road-base construction, railroad ballast, fine aggregate in concrete, etc. Some studies have attempted to recover metal values from copper slag. This research was intended to recover ferrous alloy contained Cu, a raw material of zinc, from copper slag, and produce reformed slag such as blast furnace slag for Portland cement. As a result, it was confirmed that with reduction smelting by carbon at temperatures above 1400 • C, it is possible to recover pig iron containing copper from copper smelting slag, and the addition of CaO in reduction smelting helped to reduce iron oxide in the fayalite and change the chemical and mineralogical composition of the slag. The copper oxide in the slag can be easily reduced and dissolved in the molten pig iron, and zinc oxide is also reduced to a volatile zinc, which is removed from the furnace as fumes, by carbon during the reduction process. When CaO addition is above 5%, acid slag is completely transformed into calcium silicate slag and is observed to be like blast furnace slag.

Almalyk Mining and Metallurgical Plant plans to increase copper production to 400 thousand tons by 2029. Almalyk Mining and Metallurgical Combine (AGMK) plans to increase copper production to 400 thousand tons in 2020-2028, follows from the decree of the President of Uzbekistan Shavkat Mirziyoyev of May 26. According to the document, the project for expanding the production of non-ferrous metals at AGMK is divided into two stages. In 2020-2025, the plant plans to build an open pit at the Yoshlik-I deposit, as well as a new copper-processing plant (MOF) with a processing capacity of 60 million tons of ore per year. According to the calculations of the plant, it is planned to build a factory of such capacity for the first time in the CIS. For its implementation at AGMK, similar productions were studied at copper quarries in Chile and Peru. As Gazeta.uz was informed at the plant, "the uniqueness of the new factory will be in the use of a rational scheme for the enrichment of minerals, which, among other things, will increase the production of molybdenum and gold". The resolution approved the proposal of the AMMC to attract the Russian Renaissance Heavy Industries (a subsidiary of the Turkish Ronesans Holding) for the construction of the MOF. Two contracts will be signed with the company-for the execution of engineering works and design until the end of 2020, as well as for the supply of equipment on a turnkey basis. The implementation of the first stage will make it possible to increase the output of copper at the plant to 290 thousand tons, gold-up to 38 tons, silver-up to 203 tons. In February of this year, during the visit of Shavkat Mirziyoyev to Turkey with Ronesans Holding, agreements were reached on the implementation of projects in metallurgy, medicine and real estate in Uzbekistan worth about $ 8 billion. In particular, the modernization of the AMMC provides for the attraction of funds for $ 4.1 billion. The second stage of the project (2022-2028) involves the expansion of the Yoshlik-I open pit capacity and the construction of another MPF, already the fourth at the AGMK, to process 50 million tons of ore per year. This will increase the production of cathode copper-up to 400 thousand tons per year, gold-up to 50 tons, silver-up to 270 tons.

Методические указания составлены на основании типовых и рабочих программ по курсу «Теория гидрометаллургических процессов». Данное методическое указания написан на основе предмета "Теория  гидрометаллургических процессов" и содержит в своем составе текст лекций, практических занятий и других материалов. В нем рассматриваются такие темы как, общие сведения о термодинамике электролитных растворов, термодинамика простого выщелачивания, термодинамика процессов химического выщелачивания, кинетика и механизм процессов выщелачивания, методы ускорения процессов выщелачивания, кинетика и механизм процессов выщелачивания самородков, оксидов и сульфидов металлов, основы процессов экстракции, основы ионообменных процессов, а также основы выделения металлов и их соединений из водных растворов.

Olmaliq kon-metallurgiya kombinati (OKMK) singari dunyoning aksariyat korxonalarida xomaki misni ishlab chiqarishning klassik
pirometallurgik sxemasi qoʻllaniladi. Bunga koʻra, sulfidli mis rudalari dastlab
flotatsion usulda boyitilib, tarkibida 16 – 20 % mis tutgan konsentrat olinadi.
Olingan misli konsentrat yuqori haroratda termik qayta ishlash maqsadida
metallurgik pechlarga yuklanadi. Metallurgik zavodlarda misli xomashyolarni qayta ishlashga moʻljallangan bir necha xil eritish pechlari mavjud. Ularga Yalligʻ qaytaruvchi, Kislorod-mashʼalali va Vanyukov kabi eritish pechlarini misol tariqasida keltirish mumkin. Bu eritish pechlarining ishlash prinsiplari har xil boʻlishiga qaramay olinadigan mahsulotlari bir-biriga oʻxshash boʻladi, yaʼni
mahsulot sifatida misli shteyn (30 – 50 % Cu), shlak va sanoat gazlari hosil boʻladi. Oraliq mahsulot – misli shteynni konvertorlash jarayoniga beriladi, u yerda havo kislorodi ishtirokida shteyn tarkibidagi keraksiz elementlarni oksidlantirish yoʻli bilan misni tozalab xomaki mis olinadi (96 – 98 % Cu). Soʻngra xomaki misni olovli tozalash jarayonida anod qoliplarga quyib
elektroliz jarayoniga yuboriladi va natijada yuqori sifatli misli katodlar olinadi
(99,99 % Cu).

The monograph presents theoretical approaches and concepts, analytical reviews, practical solutions in specific areas of metallurgy.
The publication may be interesting to Uzbek and foreign scientists, managers and specialists of factories and metallurgical organizations, engineers, technologists, teachers, masters and students of higher educational institutions.
Responsibility for the authenticity and accuracy of citations, names, titles and other information, as well as for compliance with intellectual property laws lies with the authors of published materials.

Uslubiy qo‘llanmada gidrometallurgiya jarayonlarining nazariy asoslariga tayangan holda bu jarayonlarda uchraydigan kimyoviy hamda termokimyoviy qonuniyatlar asosida ma’ruzalar matni ko‘rsatib o‘tilgan. Muhim gidrometallurgik jarayonlar: eritmalarda uchraydigan qonuniyatlar, moddalarning ionlarga parchalanishi, tanlab eritish jarayonlarining asosiy termodinamik ko‘rsatkichlari, аsosiy va keng tarqalgan gidrometallurgik jarayonlarning mexanizmi va kinetikasining ajralib turadigan xossalari keltirilgan bo‘lib, jarayonlarni intensivlashtirishning asosiy yo‘llari bayon etilgan.

Maqolada oltinning sianli eritmalar chiqindilari bilan isrofini kamaytirishning innovatsion usuli ko‘rib chiqilgan. Bu tadqiqotni o‘tkazish uchun zararli unsurlardan tozalaydigan va oltin saqlovchi rudalardan oltinni tanlab eritish yo‘li bilan ajratib olish uchun qulay sharoit hosil qilinishiga yordan beradigan kimyoviy reagentlardan foydalanildi. Olingan natijalar shuni ko‘rsatadiki, bu texnologiyani sanoat miqyosida qo‘llash ishlab chiqarish unumdorligini oshirishga imkon beradi.

В монографии изложены основные законы физической химии и металловедения, являющиеся основой анализа металлургических систем. Основное внимание уделено анализу изменения состояния вещества в ходе металлургического производства от исходного сырья до получения чистых металлов и их сплавов. В книге изложены теоретические основы восстановительных процессов оксидов металлов, вопросы взаимодействия в системах твердое тело – газ, твердое тело, жидкость, а также твердофазные процессы. Рассмотрены вопросы теплообмена и газодинамики в металлургических системах. Монография предназначена для студентов, магистров и докторантов, специализирующиеся в области металлургического образования. Может быть, полезна для молодых специалистов и научных работников для усовершенствования существующих технологий и создания новых.

Bioleaching of minerals is a process that allows the treatment of insoluble sulphides and insoluble oxides via hydrometallurgy, as opposed to the more traditional technology of pyrometallurgy. Bioleaching presents several technological, environmental and economic advantages as compared with pyrometallurgy, as well as some limitations. Results: In this work a general panorama of copper mining and biomining, the influence of the most relevant operating variables and their present and future situation in Chile are presented and discussed. Conclusions: Today, Chile plays an important role in the development and commercial application of bioleaching to copper ores. This background information allows predicting a brilliant future for this technology in Chile, as has been forecasted in the last years.

Hery Susanto. Analisa Pengaruh Inconsistency Feeding Di Dryer 1 dan Dryer 3
PT. Vale Indonesia Tbk. Sorowako Kecamatan Nuha Kabupaten Luwu Timur
Provinsi Sulawesi Selatan. Dibimbing oleh Andi Fadly Mustika.,ST .,Msi dan
Darwin Mahyudi., ST
Tujuan penelitian ini adalah untuk mengetahui pengaruh inconsistency feeding
terhadap proses pengolahan Bijih Nikel Laterit, penelitian ini merupakan
penelitian kuantitatif, subjek penelitian ini adalah masalah yang terjadi pada
proses transportasi Ore mulai dari stockpile menuju dryer di PT. Vale Indonesia
Tbk. Teknik pengumpulan data yang dilakukan antara lain observasi dan
pengumpulan data penunjang.
Hasil pengolahan ini diperoleh dengan keberadaan site pengolahan Bijih Nikel
yang berada di Kecamatan Nuha Kabupaten Luwu Timur Provinsi Sulawesi
Selatan untuk mengetahui pengaruh feed inconsistency dalam proses pengolahan
Bijih Nikel yang diduga disebabkan oleh Haul Truck pada saat proses
transportasi Ore.
Kata kunci : Pengolahan , Feed Inconsistency ,Ore

Konkola West Concentrator stockpile handles 55000 tonnes copper ore per day producing an average of 400 tonnes of concentrate. The grade of the concentrate is 36 to 40% TCu. The plant efficiency (recovery) is at 89% TCu. The concentrator operations include: Primary, secondary and tertiary crushing, grinding, flotation, dewatering and tailings disposal. The objective of this study was to investigate optimum grind of a blended copper ore comprising sulphide and oxide minerals with a view to achieving an optimal flotation performance in the treatment of the Konkola Copper Mines ore in Chilabombwe. This required an in-depth analysis of the mineralogy of the feed as well as tailings samples after different flotation processes involving a range of reagent types and dosage procedures. The in-depth analysis included the analysis of the percent Total Copper (%TCu) and percent Acid Soluble Copper (%ASCu) of the feed, concentrate recovered and the tails. The reagents used in the flotation process included; Sodium Isopropyl Xanthate (SIPX), Frother Zambia Konkola (FZK 245) and Sodium hydro-Sulphide (NaHS). The ore samples studied represented a high quality (HQ) ore dominated by sulphide minerals and low quality (LQ) ore dominated by oxide minerals. The project was initiated on the 18 th of August, 2015. The experimental results showed that optimization of grind for the blended copper ore at different grinding times was successfully achieved and can be used to increase the concentration of copper at KCM West concentrator.

The difference in the standard Gibbs free energy for the formation of any two oxides or sulfides is the chemical potential for selective reduction of metals from complex minerals. The magnitude of the Gibbs free energy difference is shown by plotting the univariant relationships for relevant sulfides and oxides. In this investigation, three examples of mineral sulfides are considered, and the experimental results are compared with the predicted thermodynamic calculations. These examples include the reduction conditions for nickel and iron sulfides and pentlandite (Fe,Ni)gS s and chalcopyrite (CuFeS2) minerals. The reduction behavior of mineral sulfides, such as those of nickel, cobalt, iron, and copper, is illustrated by referring to both the sulfide and alloy phase equilibria. In particular, the solution thermodynamic properties of the metallic phase equilibria are featured for determining the physical chemistry of preferential or selective reduction of the metal oxides and sulfides. The mechanism for the reduction of the aforementioned sulfide minerals is explained with the aid of the governing phase equilibria for the calcination process. The results from the carbothermic reduction of sulfide minerals are also compared. The important roles of lime and calcium sulfate in controlling the emission of sulfurous gases during the reduction reaction are explained. A qualitative analysis of reduction reactions of nickel and iron sulfides is reviewed to provide a comparison of the mechanism for complex nickel-bearing minerals. The importance of these results in producing alloy and pure metallic phases is also examined.

Ilmenite smelters must be operated with the slag bath contained in a freeze lining of solidified slag to prevent refractory damage and ensure feasible furnace life. This makes the process an interesting and challenging one to operate and control.

Numerous non-ferrous metallurgy wastes are known (dumps, slags, sludge, dust, clinker, etc.), which, from an economic as well as an environmental point of view, are beneficial and must be disposed of. This book provides an analysis of known methods and proposes new solutions for the autonomous and joint processing of zinc production cake and molybdenum cake of the leaching plant of OJSC Almalyk MMC, which are technogenic deposits of unique polymetallic raw materials, which are practically not used to date. The relevance and novelty of the problem of processing such deposits in the steady growth of their volumes and the lack of effective processing technology. These deposits differ from natural mineral raw materials in that they are a product of technological processing and are composed of new mineralogical formations, more or less persistent and difficult to process. Operating enterprises and technologies often turn out to be unsuitable for waste processing and require reconstruction, modernization or re-equipment based on new progressive technological solutions. The solutions proposed by the authors make it possible to selectively extract copper, zinc, iron, gold and silver from the specified raw materials and define the technology as environmental protection and diversification.

Thermal stabilities of selected ternary phases of industrial interest in the Ag-Cu-S system have been studied by the calorimetric and electromotive force techniques. The ternary compounds Ag1.2Cu0.8S (mineral mackinstryite) and AgCuS (mineral stromeyerite) were equilibrated through high-temperature reaction of the pure Cu2S and Ag2S in an inert atmosphere. The synthesized single solid sample constituting the two ternary phases was ground into fine powders and lightly pressed into pellets before calorimetric measurements. An electrochemical cell incorporating the two equilibrated phase and additional CuS as a cathode material was employed. The measurement results obtained with both techniques were analyzed and thermodynamic properties in the system
have been determined and compared with the available literature values. Enthalpy of fusion data of the Ag-richer solid solution (Ag,Cu)2S have also been determined directly from the experimental data for the first time. The thermodynamic quantities determined in this work can be used to calculate thermal energy of processes involving the Ag-Cu-S-ternary phases. By applying the obtained results and the critically evaluated literature data, we have developed a thermodynamic database. The
self-developed database was combined with the latest pure substances database of the FactSage software package to model the phase diagram of the Ag2S-Cu2S system.

Deoxidation is one of the important technological operations of the steel production process, the main tasks of which are to reduce the concentration of oxygen dissolved in the melt and the most complete removal of the resulting deoxidation products from the melt. In metallurgical practice, more and more often, when deoxidizing steel, the so-called. complex deoxidizers, which are alloys of several elements with a high affinity for oxygen, allowing deoxidizing steel deeper than traditional ferroalloys and obtaining a more favorable metal structure with high mechanical properties by modifying non-metallic inclusions. The essence of complex deoxidation is to increase the reactivity of elements due to more favorable energy conditions, under which the reactions of interaction of elements with oxygen dissolved in liquid steel proceed more fully.

The South African platinum industry has advanced into an era of predominantly mining and processing Upper Group Two (UG-2) ore to extract Platinum Group Metals (PGMs). Flotation concentrates derived from processing UG-2 ore are typically characterized by high chrome contents (>3 wt.%) which are not amenable to conventional PGM smelters. The net effect of high chrome, inter alia, includes increased smelting energy requirements and the reduction of effective furnace capacity. Various interventions ranging from the redesign and modification of existing physical and pyrometallurgical operations have been introduced and these have yielded no sustainable solutions. In this study, a hydrometallurgical process was investigated as an alternative route to reduce chrome in UG-2 concentrates. The parameters initially considered for investigation were acid concentration, leaching time, temperature and oxygen flowrate while keeping solid to liquid ratio and agitation rate constant. Results showed that oxygen flowrate and an interaction of temperature, time and acid concentration had a positive but minimal effect on Cr extraction. The highest Cr extraction obtained was 7.0%. Further test work entailed exploring the effect of solid to liquid ratio using optimized conditions. The results showed a substantial increase of Cr extraction of up to 37%. This represents 1.33% decrease in chrome content, from 3.63% to 2.30%, in UG-2 concentrate.

Today, the Waelz process using a rotary kiln is the best technology available for the pyro-metallurgical treatment of zinc-bearing residues. However, this process will only result in a good zinc recovery, if the temperature distribution in the kiln and the rheological behavior of the material are controlled. Unfortunately, these properties cannot be measured with conventional sensors. In this paper, an image processing system for the Waelz kiln process will be presented, which calculates the relevant process information from infrared camera images in an online manner. It uses a custom-built infrared camera with a spectral filter at 3.9 lm, which provides for a detailed insight into the kiln. The information that is calculated by the image processing system, including temperature distributions of the material, repose and filling angles, is directly used for closed loop control. The system presented has been in operation at an industrial plant in Germany for about 2 years.

The article considers the inevitability of copper losses with slag and the possibility of reducing them by various methods and using local secondary technogenic formations. It has been established that the developed and widely used in industry technologies for slag decontamination only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the losses are established and suggestions for reducing their negative impact are recommended. The use of perfect mixing devices is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to achieve an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.

The study relates to the processing of zinc-containing wastes of metallurgical production using products of joint pyrolysis of polyethylene wastes and wood pods. The process is carried out in two stages: preparation of polyethylene waste for the operation and then the recovery process. Zinc-containing wastes are thickened, dehydrated to a moisture content of not more than 10-13%, mixed with a reducing agent. Dehydrated Zinc-containing wastes (cake or sludge) are mixed with synthetic reducing agents in a mass ratio cake-artificial reducing agent from 8.8: 2.2 to 8.2: 2.8, respectively, and pelletized. They carry out reductive heat treatment of pelletized waste in the presence of a reliable carbon-containing reducing agent in the amount of 20-40% by weight of the processed waste and the resulting products of the combined pyrolysis of polyethylene waste and wood pods with counter current air blasting in a rotary kiln, distillation of zinc and trapping of sublimates to produce zinc oxides. Moreover, before igniting a reliable, reducing agent and pyrolysis products of polyethylene wastes (synthetic reducing agent), gaseous fuel is burned in the working volume of the furnace. This study will increase the intensity of the processes of sublimation of zinc and reduction of iron, increase the degree of utilization of polymer waste.

The article deals with the problem of reducing copper losses from waste slags. A comprehensive solution to the problem with the use of physicochemical methods of influence on the melt is proposed. It is shown that the success of the depletion process depends on the sulfiding of oxidized copper compounds, the reduction of magnetite in the slag to wustite, and the creation of conditions for the coalescence of fine drops of matte. Creating these conditions makes it possible to reduce the residual concentration of copper to the level applied. This can be obtained poor matte, which is processed by pouring them into a melting furnace. Depleted slag is waste products and can be implemented in the construction industry. In fact, this makes it possible to abandon the creation of slag heaps.

Thermodynamic analysis and experimental research of the chlorination of nickel ferrite (NiFe 2 O 4) by gaseous chlorine in the presence of added C, BaS, S and NaCl in the temperature range from 300 to 900aeC are given in this paper. Nickel ferrite chlorination in the presence of BaS and CaCl 2 was carried out in the temperature range from 750 to 950aeC. The presence of added C, BaS, S and NaCl intensifies the chlorination process of nickel ferrite by gaseous chlorine and reduces the temperature the reaction begins at from 700 to 300aeC. It is concluded that the process of nickel chlorination without additives is chemically controlled, whereas it is diffusion controlled in the presence of addi-Lately, the chlorination processes of various compounds (oxides, silicates, titanates) have been studied more and more [1]: thermodynamic analysis and experimental research of the chlorination of nickel silicate and nickel oxide by gaseous chlorine and calcium chloride with and without carbon, BaS, S and NaCl being added as activators are discussed in previous paper [2, 3]. This paper aims to investigate the possibilities of intensifying the process in the presence of added coal, BaS, S and NaCl and the conditions of selective chlorination of nickel and iron from nickel ferrite. The authors have also pointed out the complexity of the chlorination process and possible mechanisms of intensifying the process in the presence of the mentioned additives. Thermodynamic analysis Nickel ferrite chlorination by gaseous chlorine with and without added C, BaS, NaCl and S can be expressed by the following reactions: NiFe 2 O 4 (s)π4 Cl 2 (g)ΩNiCl 2 (s) π2 FeCl 3 (g)π2 O 2 (g) (1) 1 tives. The chlorination of nickel ferrite by calcium chloride, i.e., gaseous hydrochloric acid, is intensified in the presence of 7.5 mass % of CaCl 2 and 2 mass % of BaS in nickel ferrite, and temperature range from 750 to 950aeC. The results obtained in thermodynamic analysis are in good agreement with the experimental ones.

The article discusses an innovative method of reducing the loss of gold with waste cyanide solutions. To conduct this study, chemical reagents were used that allow the removal of harmful impurities and create the optimal conditions for the complete leaching of gold-bearing ores. The results show that the introduction of this technology in industry will increase their productivity.

The article considers the inevitability of copper losses with slag and the possibility of reducing them by various methods and using local secondary technogenic formations. It has been established that the developed and widely used in industry technologies for decopperizing of slag only partially solve the problem and lead to significant irretrievable losses of metal with dump slag. The main factors affecting the magnitude of the losses are established and suggestions for reducing their negative impact are recommended. The use of perfect mixing devices is recommended, as in this case, it is possible to achieve a maximum reduction in the residual concentration of copper in the waste slag. Together, it is possible to achieve an increase in the complexity of the use of raw materials with the organization and implementation of low-waste technology.

The splash event produced by a falling drop impinging on a bath of liquid was studied to enable a more fundamental understanding of the mechanisms of splash formation.

An experimental method involving the use of a high speed photographic technique was developed to enable discrete splash events to be recorded at different time intervals.  The effect of varying impact velocity, liqiid viscosity and surface tension on the splash event was studied.

The aspects of the splash event that pertained to the projection of liquid above the liquid surface were monitored as a function of the experimental variables.  Such aspects included the cavity depth, the Rayleigh jet behaviour and the extruded crown behaviour.

Depending on the impact velocity of the falling drop, different shaped Rayleigh jets formed which varied in their manner of break up.  Such changes in the Rayleigh jet behaviour could be related to the curvature of the interfacial cavity produced by the impact of the falling drop.  As the impact velocity increased, the maximum height of the extruded crown increased.  If the impact velocity exceeded a critical value, break up the crown occurred.  Increasing liquid viscosity had the effect of dissipating the energy of the system and hence producing less splash.  Such viscous effects were quantified by the use of an energy balance.  For liquids of lowrr surface tension, there was evidence to suggest that a greater proportion of the incoming energy to the splash event was transferred to the extruded crown rather than to the cavity.  Consequently, the spalsh produced from the break up and extrusion of the crown became more significant.

A knowledge of the size of bubbles reaching the liquid surface woupd assist in predicting the splashing behaviour of an industrial process which utilised gas injection.

The major item of concern of this work was to recover bronze alloys meeting DIN 1617 as specified applying combined hydrometallurgical and pyrometallurgical treatments. The hydrometallurgical leaching process utilizes hydrogen peroxide in ammonia to dissolve copper selectively. Lead and tin are then leached with hydrochloric acid in hot conditions. Lead chloride precipitates by cooling. Lead chloride so leached is converted into carbonate by leaching with sodium carbonate solution. Copper, lead and tin metals are recovered from the leach products by thermal reduction. Pyrometallurgical treatment involves melting with a carbon/alkali borate flux at 1150-1300°C for controlling slag quantity. Parameters affecting the recovery efficiency of the investigated methods, such as time, temperature, hydrogen peroxide concentration, and stoichiometric ratio of the leachants are given. Results obtained show that melting of bronze turnings failed to recover standard bronze alloys due to thermal volatilization of tin and escape of lead into the slag. Combined hydrometallurgical processes are significant for recovering metals as well as bronze alloys from the turnings. Hydrogen peroxide assists dissolution of the metals originally present in the scrap. Metals entering the slag are recycled in the same manner. Free metals are recovered from the leached products by thermal reduction with hydrogen or spent active carbon. The activation energy of the latter process amounts to 83.6, 12.7 and 51.73 kJ/mol for copper, lead and tin respectively. The maximum recovery efficiency of the suggested method amounts to 98.7%. A preliminary economic evaluation suggests that the process could be economically feasible.

The article considers problems of reduction of magnetite with forming bivalent iron after converting copper mattes in horizontal converters. So, it has been showed what methods of reduction of magnetite until ferrous ions with different reducing agents. The magnetite in the slag is reduced with carbonaceous materials or other solid reductants. While the slag is mixed with a water cooled, metal-bladed mechanical stirrer, the reductant is reacted with the slag. As a result of stirring the reductant into the slag, the rate of magnetite reduction is highly accelerated. With the reduction, the copper separates into a copper phase as either immiscible copper, copper sulfide, or a copper-iron-sulfide matte, depending upon the initial composition of the slag.

The major item of concern of this work was to recover bronze alloys meeting DIN 1617 as specified applying combined hydrometallurgical and pyrometallurgical treatments. The hydrometallurgical leaching process utilizes hydrogen peroxide in ammonia to dissolve copper selectively. Lead and tin are then leached with hydrochloric acid in hot conditions. Lead chloride precipitates by cooling. Lead chloride so leached is converted into carbonate by leaching with sodium carbonate solution. Copper, lead and tin metals are recovered from the leach products by thermal reduction. Pyrometallurgical treatment involves melting with a carbon/alkali borate flux at 1150-1300°C for controlling slag quantity. Parameters affecting the recovery efficiency of the investigated methods, such as time, temperature, hydrogen peroxide concentration, and stoichiometric ratio of the leachants are given. Results obtained show that melting of bronze turnings failed to recover standard bronze alloys due to thermal volatilization of tin and escape of lead into the slag. Combined hydrometallurgical processes are significant for recovering metals as well as bronze alloys from the turnings. Hydrogen peroxide assists dissolution of the metals originally present in the scrap. Metals entering the slag are recycled in the same manner. Free metals are recovered from the leached products by thermal reduction with hydrogen or spent active carbon. The activation energy of the latter process amounts to 83.6, 12.7 and 51.73 kJ/mol for copper, lead and tin respectively. The maximum recovery efficiency of the suggested method amounts to 98.7%. A preliminary economic evaluation suggests that the process could be economically feasible.

The article discusses the problems of studying the properties of copper slag and the factors affecting them. The laws of change of slag properties at different temperatures are shown. Accordingly, the main properties of copper slags are their density, viscosity and surface tension. Based on the properties of the slag, they show the laws of dispersion of matte droplets. The laws of leakage of matte droplets from a layer of high-temperature liquid slag and their mathematical expressions are given.

Refractory linings of metallurgical furnaces have two main purposes: to control the heat flow, and to contain high temperature liquids (metal and slag). Through a proper management of heat flows, a layer of slag called freeze lining crystallizes on the internal walls of the furnace thereby protecting the bricks from the very corrosive high temperature liquid slag. The thickness, stability and properties of this frozen slag are key parameters for the performance of a safe and stable process. In situ observations of the crystallization process during furnace operations are very difficult. To overcome this difficulty, the present work proposes a combination of heat flow monitoring, numerical modeling of heat transfer and the mineralogical characterization of the residual freeze lining after the furnace operation. The combination of these tools helps with the management of the process and the understanding of how to preserve the thermal balance of the furnace and the stability of the refractory lining. Within a pilot furnace freeze lining, physical and chemical properties change depending on the operation parameters. The thickness of the free lining is one of the most important process variables to follow-up. An inverse heat transfer issue is solved using the software FLUENT in a simplified 2-D axisymmetric geometry of the furnace. After completion of the pilot, the freeze lining of the furnace is analyzed and characterized. All the significant evolutions in the operating parameters (temperature variations, slag chemistry changes) are recorded within the oxide layers of the skull. Additionally to characterization, the crystallization paths that occurred during the process can be calculated using thermodynamic equilibrium computations. This work provides a multi-disciplinary approach to understand usually unobservable phenomena within the furnace, allowing an estimation of the thickness, and physical and chemical properties of the freeze lining inside furnace.

Among the rare earth minerals, fluorides, phosphates, and oxides have received attention from the rare earth industry. Traditional methods of decomposition of these minerals, usually alkaline or acid processes, involve several operations. Another possibility to obtain lanthanide chlorides or oxychlorides is reacting the mineral with chlorinating agents, such as gaseous chlorine, hydrogen chloride, thionyl chloride, and carbon tetrachloride, reducing the operation costs and making the process less complicated. In this context, we investigated the decomposition of xenotime using carbon tetrachloride at temperatures from 873 to 1173 K and kinetic and mechanistic studies have been performed. Powder X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectrometry, ultra-violet/ visible spectroscopy, and thermal analysis techniques were used in this study. The results showed that the reaction follows the shrinking-unreacted-core model with formation of a product layer (lanthanide oxychloride), confirmed by powder X-ray diffraction. Moreover, microstructural changes of xenotime grains during the chlorination reaction were verified.

Metallic ore grades are falling globally as the higher grade reserves are exploited first and are progressively depleted. At the same time, the demand for primary metals extracted from these ores is expected to increase, despite increased levels of dematerialisation and recycling. Sustainability concerns have highlighted the need to meet these demands while at the same time minimising resource consumption and environmental emissions. A study was therefore undertaken using life cycle assessment methodology to examine various alternative processing routes for extracting metal from low grade ores (down to 0.1% metal), particularly those of copper and nickel, in terms of their life cycle-based energy consumption (embodied energy) and greenhouse gas emissions. The processing routes examined included conventional concentrating and smelting, direct ore smelting, heap leaching, pressure leaching and in situ leaching. This paper presents the results of this study.

The reaction of single sintered pellets of alpha-Nb2O5 with chlorine and carbon monoxide was studied in the temperature range from 773 K to 1073 K using a thermogravimetric apparatus. The rate controlling step of the reaction was determined from experiments carried out at variable gas flow rates, gas composition, surface geometry, pellet porosity and temperature. The vapor phase transport reaction can be written as:
Nb2O5 (s) + 3Cl2 (g) + 3CO (g) = 2 NbOCl3 (g) + 3 CO2 (g)
Up to 60% conversion, the amount of volatilized product was found to be directly proportional to the time reaction. The external surface area of the pellets remains unchanged up to this stage while the intergranular morphology changes.
These results were compared with reaction rates of commercial pyrochlore concentrate in order to establish the fundamental reaction stages of the process of extraction of Nb2O5 from pyrochlore.