Matte Smelting Process Research Articles

Selective alkaline leaching of antimony from Low-grade refractory gold ores and process optimization

To eliminate the adverse effect of antimony on extracting of gold in matte smelting process from Sb-bearing refractory gold ores, the sodium sulfide leaching method was proposed to selectively remove antimony in advance. On the basis of the analysis and characterization of raw materials (XRD, SEM-EDS, mineralogical phase analysis, etc.), it can be detected that the antimony in refractory gold ores is mainly in form of stibnite with small quantities of oxides, and the gold is mainly wrapped up in sulfides and silicates. The effects of sodium sulfide and sodium hydroxide concentration, temperature, leaching time and liquid–solid ratio on the extraction rate of antimony and gold were discussed. Furthermore, the response surface method was applied to distinguish the interaction influence of process parameters on the antimony and gold extraction rate. It is detected that the polysulfides and thiosulfates are the main cause of associated leaching of gold. Furthermore, the regression equation model is established adopting the antimony extraction rate as response value, and it can be deduced that the relevance degree is Na2S concentration > temperature > NaOH concentration. Accordingly, the optimized process results are determined as follows: the extraction rates of antimony and gold reach 94.15% and 3.37%, respectively, under Na2S concentration of 85.66 g/L, NaOH concentration of 45.5 g/L, liquid–solid ratio of 1.5, leaching at 90 °C for 5 min, which are very consistent with the predicted values of the regression equation, proving the feasibility of the proposed optimization model.

Comprehensive use of raw materials through optimization of the concentration and metallurgical complex of Norilsk division

Using a concentration process introduced in 2016, Talnakh Concentrator produces copper and nickel-pyrrhotite concentrates by processing high-grade and cupriferous ores. Dump tailings comprise rock tailings separated at the early process stage and low-nickel pyrrhotite product obtained at the final concentration stage. The predominant mineral found in the ores processed by Talnakh Concentrator includes pyrrhotite, which in most cases contains nickel. Low-nickel pyrrhotite product contains pyrrhotite that bears maximum Ni 0.4% in the form of impurity. Another feature characterizing the pyrrhotites found in Norilsk is the presence of isomorphic inclusions of platinum group metals. Aimed at a more comprehensive use of raw materials, in 2018 Talnakh Concentrator introduced a process for repreparation of low-nickel pyrrhotite concentrate. A low-grade flotation concentrate is obtained with Ni 0.8÷1.2%, which is then sent to the hydrometallurgical circuit of Nadezhda Metallurgical Plant named after B.I. Kolesnikov (NMP). Being a sulphide, pyrrhotite enhances the autogenic performance of matte smelting process. The nickel concentrate produced by Norilsk Concentrator from disseminated and cupriferous ores is a low-energy material containing 15–17% of sulphur. So the heat generated during its oxidation flash smelting is insufficient to maintain the heat balance of the furnace. The nickel concentrate produced by Norilsk Concentrator is processed mixed with Ni-containing burden, which lowers the total heat balance of the flash smelting furnaces at NMP. In 2021, a process was introduced when a part of the tailings from the low-nickel pyrrhotite concentrate line of Talnakh Concentrator is used to recover high-pyrrhotite concentrate to be added to the nickel concentrate produced by Norilsk Concentrator in order to improve th e latter’s energy performance.

Smelting Experiments with Chalcopyrite Ore based on Evidence from the Eastern Alps

In order to assess the fractionation of copper isotopes during smelting under reconstructed conditions, smelting experiments with chalcopyrite ore were conducted in built furnaces based on archaeometallurgical evidence from the Bronze Age Eastern Alps and ethnographic examples from Nepal. Two experimental series, S2 and S4 were chosen for analysis. Each series consisted of a number of roasting and smelting experiments with different experimental parameters, and both series yielded metallic copper. Each type of experiment, their outcomes, and observations made during them are described in detail to facilitate future experimental work. Both series differ significantly in their outcome. XRD analyses and chemical analyses were carried out to reveal the reasons for the observed differences. The chemistry of the obtained matte shows that roasting is pivotal for a successful smelting process and that two cycles of matte roasting and subsequent smelting can be sufficient to remove most of the sulphur and iron from the matte. Furthermore, different conditions in the shaft furnaces resulted in a more efficient oxidation of iron in series S4. During the subsequent smelting of the matte in the pit furnace, it was possible to extract larger amounts of metallic copper and sponge copper, as well as to produce a thin well-melted plate-like slag. The pit furnace did not always show clear traces of metallurgical activity and thus might not be identifiable in the archaeological records without chemical analysis of the pit lining and surrounding soil. Although more trials are needed to replicate the process, these experiments give a strong hint towards the reconstruction of the matte smelting process in the Bronze Age alpine area.

Copper production and supra-regional exchange networks – Cu-matte smelting in the Balkans between 2000 and 1500 BC

The Balkan Peninsula played a crucial role for the introduction of metallurgy during the Copper Age and numerous archaeometallurgical examinations have delivered highly interesting insights on this topic. However, there is a lack of systematic analytical research on copper ore smelting and metal exchange for the later Bronze Age. In this paper we focus on the first archaeometallurgical results of slags from the sites Ružana, Trnjane and Čoka Njica, Eastern Serbia, complimented by the discussion of XRF and lead isotope analyses carried out on 28 copper-based artefacts. Importantly, radiocarbon dating from these sites points to copper production already being undertaken at the end of the Early Bronze Age (19th–18th centuries BC), more than 500 years earlier than previously assumed. This enables us to investigate the flow of metal during the 1st half of the 2nd millennium BC. The analyses of the metallurgical slags indicate a copper matte smelting process in small open pit furnaces and the use of local sulfidic copper ore sources. The fact that these intensive smelting activities in Eastern Serbia can be paralleled with the early production hotspots in central Europe e.g. on the Hochkönig (Mitterberg mining areas) sheds new light on the development of copper based metallurgy in Europe. At the same time, the evidence from Eastern Serbia shows that this area was a source of raw material for copper and bronze alloys providing a regional and supra-regional perspective. Furthermore, our analyses revealed the remarkable result, that by the start of the Middle Bronze Age (ca. 1700 BC) copper from the Northern Italian mining areas in the Trentino region also reached the western and central Balkans.

Tracking Alpine copper—analysis of Late Bronze Age copper ingot hoard from South Bohemia

We present the results of a complex archaeometric study of Late Bronze Age copper ingots from the Stare Hodějovice hoard (South Bohemia). In order to understand the origin of the copper and describe the metallurgical process, we use modern analytical methods (metallography analyses, major/trace element and lead isotope analyses) to describe the samples. Within this study, a representative dataset of trace element composition and lead isotope ratios of non-alloyed and non-recycled corpus of copper ingots from the Late Bronze Age was created. We assume that most of the ingots were not altered by alloying, mixing or recycling. Based on lead isotope ratios and major/trace element composition, we suppose that the origin of the copper could be mostly Alpine ores from the Trentino and Mitterberg regions and possibly the Valais region. By this study, it was proved that copper smelted by a matte smelting process was transported in the form of flat or plano-convex ingots from multiple sources to South Bohemia, where it was subsequently refined and alloyed. Obtained analytical results refute the idea of prevailing copper recycling in the Late Bronze Age.

Application of novel big data processing techniques in process industries

Modern process engineering industry offers great opportunities for harvesting tremendous amounts of data, both structured and unstructured. However, significant volumes of information as well as frequently encountered inconsistencies, missing values and other discrepancies render data processing with traditional tools rather inefficient. New software solutions are being constantly developed to address this challenge, yet, as regards analytics of actual industry related data, adaptation of these instruments has been comparatively limited so far. Consequently, within the limits of this work, applicability of novel analytical instruments in the context of process engineering industry is studied for both structured and unstructured data processing. In the former case, the data describing the copper matte smelting process is analysed focusing on identification of interdependencies between key process parameters and products' properties, while in the latter case, a collection of relevant scientific articles is investigated with a view to extracting key concepts and determining major relations among them.

Application of novel big data processing techniques in process industries

Modern process engineering industry offers great opportunities for harvesting tremendous amounts of data, both structured and unstructured. However, significant volumes of information as well as frequently encountered inconsistencies, missing values and other discrepancies render data processing with traditional tools rather inefficient. New software solutions are being constantly developed to address this challenge, yet, as regards analytics of actual industry related data, adaptation of these instruments has been comparatively limited so far. Consequently, within the limits of this work, applicability of novel analytical instruments in the context of process engineering industry is studied for both structured and unstructured data processing. In the former case, the data describing the copper matte smelting process is analysed focusing on identification of interdependencies between key process parameters and products' properties, while in the latter case, a collection of relevant scientific articles is investigated with a view to extracting key concepts and determining major relations among them.

Behavior of Waste Printed Circuit Board (WPCB) Materials in the Copper Matte Smelting Process

The amount of waste electrical and electronic equipment (WEEE) in the world has grown rapidly during recent decades, and with the depletion of primary ores, there is urgent need for industries to study new sources for metals. Waste printed circuit boards (WPCB) are a part of WEEE, which have a higher concentration of copper and precious metals when compared to primary ore sources. PCB materials can be processed using pyrometallurgical routes, and some industrial processes, such as copper flash smelting, have utilized this type of waste in limited amounts for years. For the purpose of recycling these materials through smelting processes, this work studied the behavior of WPCB scrap when dropped on top of molten slag. A series of experiments was carried out during this research at a temperature of 1350 °C, in an inert atmosphere with different melting times. The time required for complete melting of the PCB pieces was 2–5 min, after which molten alloy droplets containing Cu, Pb, Sn, Ni, Au, and Ag formed and started descending toward the bottom of the crucible. The ceramic fraction of the PCB material mixed with slag and the polymer fraction was pyrolyzed during the high-temperature experiments. The results give an understanding of PCB melting behavior and their use as a part of the smelting furnace feed mixture. However, more research is needed to fully understand how the different elements affect the process as the amount of PCB in the feed increases. The physical behavior and distribution of PCB materials in fayalite slag during the smelting process are outlined, and the results of this work form a basis for future studies about the chemical reaction behavior and kinetics when PCB materials are introduced into the copper smelting process.

Self-Assembly of Metal Oxide Nanoparticles in Liquid Metal toward Nucleation Control for Graphene Single-Crystal Arrays

Summary We have achieved the spontaneous assembly of alumina nanoparticles on a liquid metal surface and further synthesized a very-large-scale graphene single-crystal array. The effective electrical field established as a result of the electrical charge of the alumina nanoparticles in the liquid metal ensures the ordered self-assembly of the alumina islands and lays the foundation for precise spatial control of graphene nucleation, leading to the formation of graphene single-crystal arrays. In addition, controlling the density of the alumina in the liquid metal can precisely tune the periodicity of the arrays. This simple strategy, which is unlike the usual solid/aqueous solution system, opens up new territory for nanoparticle assembly. Focusing on the origin of the nanoparticle interaction that drives the self-assembly of ordered structure in the liquid metal system is a promising avenue for triggering more interesting applications.

New Slag for Nickel Matte Smelting Process and Subsequent Fe Extraction

Large quantities of residual slag with high Fe content are left behind in pyrometallurgical nickel processing. How to separate and recover iron from the high fayalite residue is still a problem because iron mainly exists as iron-magnesium silicate in slag. This article suggests that the slag for nickel smelting is adjusted by increasing the amount of lime, partly instead of quartz, to form liable reduction compounds for subsequent Fe extraction. Based on the thermodynamic analysis and phase diagram of the FeO-SiO2-CaO-MgO slag system, the new slag composition was chosen, the suitable melting point of relevant slags was measured, and the phase change was observed. The new slag with a composition of 7 to 9 pct MgO, 10 to 15 pct CaO and 1.5 to 1.8 Fe/SiO2 was found to work well for nickel matte smelting. With the increase of CaO and decrease of SiO2 content in slag, Ca(Fe, Mg)Si2O6 and Mg(Ca)Fe2O4 are the main existing phases instead of (Fe, Mg)2SiO4 in the residual smelting slag. More than 50 pct of Fe-containing phases are in the form of MgFe2O4 when 15 pct CaO is added, which is what we want because the MgFe2O4 is much better for magnetic separation and reduction than the original (Fe, Mg)2SiO4. In this way, Fe can be much more easily extracted from residual slag and have multipurpose benefits.

Influence of copper slag and metakaolin on the durability of self compacting concrete

Now-a-days, researchers are endeavoring to discover new substitute materials to elucidate the scarcity of natural aggregates in the construction industry. One such alternative is copper slag (CS) obtained as byproduct during the matte smelting process of copper metal. The present investigation is aimed to assess the durability of self compacting concrete (SCC) incorporating copper slag (CS) as fine aggregates and metakaolin (MK) as substitute to fly ash (FA). A total of seven concrete mixes were prepared. The control concrete contains 60% ordinary portland cement (OPC), 40% FA and 0% CS whereas other six mixes contains constant percentage of 60% OPC, 30% FA, 10% MK with different proportions of CS from 0% to 100%. Results revealed that fresh properties declined with inclusion of MK although escalated with increment of CS content. All SCC mixes exhibited higher compressive and splitting tensile strength in comparison to control concrete. The minimum carbonation depth was marked for 100% CS substitution with 10% MK as replacement to FA. The maximum electrical resistivity and resistance to sulfate attack were obtained for 20% CS substitution while UPV values of whole mixes were under the excellent quality of concrete beyond 7 days of curing. On full replacement of sand by CS with 10% MK, initial surface absorption and sorptivity were significantly lower than control concrete at each curing period. This study suggests that CS together with MK can be a potential substitute to natural sand in the construction sector to overcome the scarcity.

Mechanical Properties and Durability of Concrete with Water Cooled Copper Slag Aggregate

Copper slag is a voluminous waste material obtained during the manufacturing of copper (matte smelting process). As its disposal becomes a concern for environmental protection agencies and governments, possible alternative outlets for this waste material are needed. The paper presents a laboratory study on CEM-II concrete mixes, containing water-cooled copper slag waste material for a partial or full replacement of fine concrete aggregate. A series of tests were performed at two different water to cement ratios, to determine the workability, cube compressive strength, indirect tensile strength, static modulus of elasticity, and a number of durability-related characteristics (water absorption, accelerated corrosion, carbonation, alkali-silica reaction). The results showed that water-cooled copper slag had variable effects on the resulting fresh or hardened concrete properties, depending on the sand replacement level and water to cement ratio. However the measured strength values were likely to be linked to the usual variability of concrete batches, rather than a significant effect of the copper slag aggregate. This hypothesis was further supported by statistical analysis. Concerning the durability related characteristics, the overall performance of the concrete containing copper-slag was in most cases similar or better than that of normal concrete with natural sand aggregate. Based on the results water-cooled copper slag can therefore be considered to be a suitable fine aggregate for concrete. This shows promise for developing an additional viable solution to tackle the issue of copper slag waste.

Dimensional Analysis of Average Diameter of Bubbles for Bottom Blown Oxygen Copper Furnace

Average diameter of bubbles is important in copper furnace. Based on the principle of similarity, a slice water model of a furnace with bottom-blown oxygen in matte-smelting process was established. A high-speed camera was used to record images continuously and clearer pictures were selected for treatment. Finally, image processing software was used for obtaining the average diameter of the bubbles. The effects of different injection conditions and equipment factors such as the diameter of nozzle, the nozzle installing angle, and gas velocity on the average diameter of bubbles were studied with cold water model experiment, exploring the dispersion and disintegration rules of bubbles. According to experimental data and Buckingham’s theorem, by using dimensional analysis method, an empirical formula on average diameter of bubbles was established (dB=0.41666d0.29374θ-0.46572v-0.16725). It can be seen from the formula that nozzle installing angle and diameter of nozzle make the most impact on the average diameter of bubbles in bottom blown oxygen copper furnace.

Furnace structure analysis for copper flash continuous smelting based on numerical simulation

According to the innate characteristic of four types of furnace, the copper flash continuous smelting (CFCS) furnace can be considered a synthetic reactor of two relatively independent processes: flash matte smelting process (FMSP) and copper continuous converting process (CCCP). Then, the CFCS thermodynamic model was proposed by establishing the multi-phase equilibrium model of FMSP and the local-equilibrium model of CCCP, respectively, and by combining them through the smelting intermediates. Subsequently, the influences of the furnace structures were investigated using the model on the formation of blister copper, the Fe3O4 behavior, the copper loss in slag and the copper recovery rate. The results show that the type D furnace, with double flues and a slag partition wall, is an ideal CFCS reactor compared with the other three types furnaces. For CFCS, it is effective to design a partition wall in the furnace to make FMSP and CCCP perform in two relatively independent zones, respectively, and to make smelting gas and converting gas discharge from respective flues.

Zinc recovery from the water-jacket furnace flue dusts by leaching and electrowinning in a SEC-CCS cell

Zinc containing flue dusts generated during a copper matte smelting process in a water-jacket furnace was leached in a zinc electrowinning return solution at 55 °C. Ninety percent of the metal was dissolved after 2 h of treatment. The leaching residues contained near 43 wt.% PbSO 4. Iron was removed from leaching solutions by precipitation using a saturated lime solution at pH 3–4. The precipitate formed mainly consisted of gypsum CaSO 4.2H 2O. Iron and magnesium co-precipitated into a chloro-hydroxide compound. No zinc compound had co-precipitated during iron removal. Copper and germanium contents lower than 10 mg/l were achieved by solvent extraction using 10% LIX 64N and cementation. Cobalt contents lower than 1 mg/l in the solution were achieved by cementation on zinc granules for 2 h at 72 to 82 °C in presence of antimony. Cadmium contents of solutions were reduced to 10 mg/l by cementation on zinc granules at room temperature. Electrons transfer regime was identified as a limiting step during zinc electrolysis in a symmetric electrolysis current–continuous circulating system, SEC-CCS. Electrolysis current efficiency higher than 94% and 3.5 kWh/kg of specific energy consumption was achieved under 500–600 A/m 2 at 35 to 40 °C in the presence of gelatine.

Characterization of products emanating from conventional and microwave energy roasting of chalcopyrite (CuFeS2) concentrate

Chalcopyrite concentrate (83% CuFeS2, 3% FeS2 and 14% ZnS) which is a typical feed to the matte smelting process for copper extraction via pyro metallurgical route has been roasted with microwaves. Comparison of mineralogical phases obtained was made with the case of conventional roasting. Resulting calcines were characterised with Mossbauer spectroscopy and XRD. It was observed that complete oxidation (dead roasting) of the chalcopyrite was achieved after 10 min with microwaves while 20 min were required in the conventional route. The mineralogical phases found in the deadroasted calcines produced from microwave roasting of this chalcopyrite concentrate were the hematite (Fe203), franklinite (ZnFe2O4), copper-rich ferrite (Cu1−x Zn x Fe2O4, x≤0.5), and copper ferrite (CuFe2O4). The findings of this work indicated that it was technologically feasible to oxidize the chalcopyrite with microwaves using a 2.45 GHz multimode applicator.

A thermodynamic model of nickel smelting and direct high-grade nickel matte smelting processes: Part I. Model development and validation

A thermodynamic model has been developed to predict the distribution behavior of Ni, Cu, Co, Fe, S, As, Sb, and Bi in the Outokumpu flash-smelting process, the Outokumpu direct high-grade matte smelting process, and the INCO flash-smelting process. In this model, as many as 16 elements (Ni, Cu, Co, Fe, As, Sb, Bi, S, O, Al, Ca, Mg, Si, N, C, and H) are considered, and two nickel sulfide species are used to allow for modeling of sulfur-deficient mattes. The compositions of the matte, slag, and gaseous phases in equilibrium are calculated using Gibbs free energies of formation and the activity coefficients of the components derived from the experimental data. The model predictions are compared with the known industrial data from the Kalgoorlie Nickel Smelter (Kalgoorlie, Australia), the Outokumpu Harjavalta Nickel Smelter (Harjavalta, Finland), the INCO Metals Company (Sudbury, Canada), and from a number of experimental data. An excellent agreement is obtained. It was found that the distribution behaviors of Ni, Co, Cu, Fe, S, As, Sb, and Bi in the nickel smelting furnace depend on process parameters such as the smelting temperature, matte grade, and partial pressure of oxygen in the process.

Some Experiments in Prehistoric Copper Smelting

It is demonstrated that workable metallic copper can be produced by a simple two-stage process from chalcopyrite ore. This simpler process could have been in use before the more complicated multi-stage matte smelting process described in the historical documents on early technology. The simpler process would probably have been operable by any society in prehistory which possessed two-tiered pottery kilns. This simpler process may have been supplanted before recorded history by the matte smelting process because the latter permits recovery of precious metals (gold and silver).