8TH INTL. SYMP. ON SUSTAINABLE NON-FERROUS SMELTING & HYDRO/ELECTROCHEMICAL PROCESSING
Editors: F. Kongoli, J. Antrekowitsch, T. Okura, Z. Wang, L. Liu, L. Guo, J. Ripke, E. Souza.

LI Dong—bo，LIANG Shuai—biao

Based on the latest operating practices of copper smelting technology, as well as confronting problems and challenges，a new eco—friendly and short—circuit copper production technology is presented in this thesis. Compared with traditional process of copper pyrometallurgy, smelting-converting-fire refining, the smelting slag is cooled slowly and then mineral processing, the process is long. Three furnaces are used in this process to replace the traditional pyrometallurgical process. The copper smelting furnace, anode—producing furnaces and CR(comprehensive recovery) furnace，which are connected integratedly．It is outstandingly featured with greatly shortened smelting process flow，high comprehensive recovery of valuable metals，high energy efficiency and good environmental performance，which provides a new route for upgrading copper smelting technology．

This paper presents that the CO₂ footprint of cement can be reduced significantly by blending Portland cement clinker with thermally activated (calcined) clays (CCs). Investigations on pure meta phases obtained via calcination of kaolin, montmorillonite, illite and muscovite reveal that they increase water demand and decrease workability of the cement. The effect depends on fineness and internal porosity of the calcined clay and the chemical composition of the native clay, with illite and kaolin behaving much less favorably than montmorillonite or muscovite. A comparison of three industrial calcined samples of mixed layer clays originating from natural clay deposits in Germany, India and China confirmed the increased water demand of composite cements holding up to 40 wt. % of these calcined clays. The increase in water demand correlates well with the amorphous part and the content of meta kaolin in the calcined mixed layer clay. For one sample holding ~ 50 % meta kaolin, an increase in superplasticizer dosage of ~ 400 % as compared to neat OPC was recorded. Whereas, a high content of meta kaolin proved to be favorable with respect to early strength development as a result of its high pozzolanic reactivity. It can be concluded that calcined clays offer the potential of significant CO₂ reduction in cement manufacture, however this comes at the price of higher admixture dosages for superplasticizers. Still, a substantial savings in CO₂ emission can be realized, and the cement industry can progress into an era of more eco-friendly binders.

In Europe, construction including heating & coaling of buildings amounts for 40
% of total CO2 emission and hence presents by far the largest source of CO2
release. Globally, a similar situation exists. The paper presents current steps in
the construction industry to dramatically reduce its CO2 footprint which include:
1) Migrate to low or zero carbon binders by replacing Portland cement clinker
with calcined clay, slag etc. Currently, cement manufacture accounts for ~ 8
% of total global CO2 emission, just behind coal, oil and gas.
2) Capture CO2 released in cement plants and utilize for concrete hardening
or dispose on CCS wells.
3) Identify CO2 stable new cements which can be used on CCS wells
4) Make highly effective thermal insulation materials mandatory on buildings.
5) Introduce concepts for mega cities to avoid unnecessary heat-up by having
plants on facades, roofs, etc. to provide a sun shelter and absorb CO2.
6) Switch from heating using fossil fuel to “green” energy including solar,
geothermal and wind energy.
7) Discourage the use of wood in construction, as we need more trees as a
natural sink for CO2.
These measures require a complete reset of our current construction processes
and will result in a huge transformation of this industry.

FLOGEN Technologies Inc. has developed an integrated Design/Decision-Making/Control/Optimization/Automation System for Pierce Smith Converters (offline and on-line) that combines several needs on supply side (in origin and from previous reactors), on production side, on metal sales side and on financial side. It supports cost prediction and cost follow up on the energy and consumables side and is integrated with databases that manages numerous types of essays.
The system instantaneously makes a complete optimization of all raw materials, including limestone, silica, enriched air volumes etc, to achieve specific targets according to the needs of the company. The results indicate the possibility to decrease the amount of silica used as a flux, minimize the slag and copper blowing time, maximize the use of reverts, minimize slag volume, and decrease copper losses in the slag. The system finds the optimum of the charge among various scenarios while the main process parameters (such as bath temperature, sulfur content in the blister and copper in the slag) are calculated during the operation, providing a clearer overview of the process, and supporting the determination of slag and copper blowing end point. The presentation will describe some of these achievements.
CONTOP system was also successfully used to determine the annual procurement strategies by predicting various raw material cost-based scenarios related to productivity and fuel consumption in short- and long-term future.
CONTOP increased productivity and reduced cost up to the highest designed limit of the technology. CONTOP also changed the way of operating from a reactive wait-the-lab-results-approach to a proactive forecast-and-act approach.

New ore-processing plant projects often face problems in processing more complex and fine-grained minerals, resulting in additional costs and lengthening the crushing and grinding schemes to sufficiently unlocking. This trend could lead to an increase in energy consumption by a factor of 4 or more by 2030 compared to today. Already today about 2% of the electricity produced worldwide is used for this purpose. Thus, reduction of specific electric power consumption in processes of disintegration and enrichment of mineral raw materials is the actual task, taking into account the tendency to economy of natural resources, and also decrease impact on environment at processing of mineral raw materials [1-2].
One of decision way of problem is selective disintegration. A reasonable application of selective disintegration would not only allow the rock mass to be broken down to the required size, but also preconcentration at the classification stage to produce a pre-concentrate and to discharge the waste rock to the tailings [3-4].
Gold ores from the Bamskoe deposit were chosen as the object of study. Analysis of the material and chemical composition was carried out using atomic absorption, X-ray fluorescence method (Shimadzu EDX-7000). For mineralogical studies, optical methods of analysis, electron microscopy etc. were used in the work. Morphometric indicators were studied using computed tomography (SkyScan-1173 microtomograph). Experimental investigations were carried out on various installations: jaw crusher, roller crusher, impact crusher, ball mill, JK Drop Weight tester, Bond impact test, Bond ball and rod mill, Mastersaizer laser diffractometer, etc.
Based on the strength and disintegration test data on mineralogical, textural and structural and physical properties of the minerals and on studies of ores crushing from the Bamskoe deposit in different types of crushers, it was found that rock-forming minerals are concentrated in large classes, especially in product of impact crushers (up to 81.85% of silica minerals in class - 4 + 2 mm).
Based on the data obtained on testing of strength properties and disintegration indices from mineralogical, textural and structural and physical-technological properties of minerals and studies conducted on crushing ores of the Bamsky deposit in different types of crushers, it was found that the products of all crushers are characterised by a predominance of -4+2 mm class. As silica-minerals are the main rock-forming minerals, it was decided to look at the distribution of Si by size classes. In analysing the distributions of silica minerals, it was found that the extraction of silica minerals was maximised for the -4+2 mm grain size class. However, the impact crusher products are characterised by the highest recovery of silica minerals in this class (up to 81.85%). These results suggest that the impact crusher at the crushing stage can selectively break down this type of mineral at the fusion boundaries.
This work was supported by the Russian Science Foundation (Рroject No. 19–17–00096).

Conservation and reuse of natural resources in the construction industry are becoming crucial to maintain sustainable and environmentally friendly construction. The use of recycled aggregates (RA) and treated wastewater (TWW) in concrete has been widely studied in the literature over the past years. It has already been shown that replacing 20% to 30% of natural aggregates with RA and replacing TWW with tap water have negligible effects on the mechanical and durability properties of concrete [1-4]. However, only a limited number of studies were conducted to study the combined effect of using RA and TWW combined in concrete. In a study conducted by Tenjhay et al. [5], it was concluded that the use of RA and TWW combined in concrete is possible after additional research is conducted to study the durability. Therefore, the main aim of this study was to evaluate the mechanical properties and durability characteristics of concrete developed using 20% recycled aggregate and secondary treated wastewater subjected to different exposure conditions of tap water, treated wastewater, and salt water. Overall, the results showed that the use of 20% RA and TWW is only substantial on mechanical properties when concrete is exposed to either TWW or SW. The durability results on the other hand showed that all the mixes were considered durable in terms of chloride ion penetration (RCPT & resistivity results), however, additional tests are necessary to precisely study the impact of different variables on concrete durability.

The inability to extract nanoparticle size of gold is one of the reasons for the high losses of valuable components with tailings during benefication of gold-bearing ores. A promising direction for the development of technologies for processing of noble raw materials is the use of various methods of physical and energy impacts on raw materials and enrichment products. Examples of such effects may be microwave [1], electric pulse [2], magnetic pulse, electrochemical, ultrasonic and other types of effects. Such research in the field of microwave treatment application was conducted in the field of auxiliary beneficiation processes (drying), ore preparation (crushing and milling) and metallurgical processing (leaching, sintering) [3-4].
Flotation experiments were carried out on Laarmann Flotation Bench Test Machine. Elemental composition analysis was carried out using Shimadzu EDX 7000 X-ray fluorescence analyzer. Determination of gold content in the sample was carried out using atomic absorption analysis, the content of organic carbon was determined on the analyzer of organic carbon TOC-L, firm Shimadzu. For microwave treatment of samples a laboratory microwave oven was used. Analysis of products after microwave treatment was carried out using MV 2300 scanning electron microscopy, CamScan and a Mastersizer 2000 particle size analyzer from Malvern Instruments.
For the investigated ores it was obtained that the main ore minerals are pyrite and arsenopyrite, barite, chalcopyrite and other minerals are present in insignificant amounts, the main rock-forming minerals are quartz, mica, carbonates and clay-sericite minerals. Contrasting surface properties of minerals with similar technological properties can be increased by applying different energy effects (MEMI, MIO, microwave, electrochemical treatment, etc.) at successive stages of raw material transformation, by regulating slurry conditioning conditions (duration and intensity of mixing, thermal treatment of slurry), as well as by developing and using selective reagent regimes. The analysis of obtained data confirms the possibility of enlarging low-dimensional noble metal particles using microwave treatment.
On the basis of conducted research, the technology of extraction of low-dimensional structures of noble and non-ferrous metals based on application of physical and energy impact methods and application of flotation methods of extraction of valuable components with a modified "carrier" was developed. It was determined that pyrite predominates in carbonaceous flotation tails, arsenic content in the tails is 0.04%. Microwave treatment of carbonaceous tailings with furnace power of 1000 W and treatment time of 12-15 minutes for enlargement of nanoparticle size of gold to the size of a few microns was substantiated.
This work was supported by the Russian Science Foundation (Рroject No. 19–17–00096).

Globally, we have established the sustainable development aim with an emphasis on social inequities reduction, economic growth, and the security of food, water, energy, and the environment as well as against global warming and climate change.
Coal is one of essential resources to provide economic and energy demands of Mongolia. Hence, a transition to clean innovative coal technologies that reduce CO2 emissions is urgently needed in order to satisfy global environmental requirements as well as to achieve sustainable economic growth and energy security of Mongolia. Clean coal technologies including pyrolysis, gasification, and chemical catalytic conversions, can process coal at molecular level and convert it into high efficiency electricity, hydrogen, synthetic natural gas, liquid fuels and various kinds of chemical products [1].
Furthermore, mining and mineral processing plants have been developed as a leading sector of the economy, production that uses natural resources dominates, and the amount of waste and piles increases every year, causing some environmental and social issues. In Mongolia, 54.4-56.2 million tons of waste generates annually from the processing plant of Erdenet and Oyutolgoi companies, which produce copper concentrate, continue to accumulate in tailings storage facility.
Accumulated waste has a unique mineral compositions and has the potential to become a source of various minerals, from which non-ferrous and rare precious metals, construction materials (sand, gravel, clay, sorghum, etc.) can be used. The practice of separating non-ferrous and rare metals into concentrates or pure metals by special enrichment methods is entering the industry. More recently, Mongolia has built its first-ever European high-tech metal powder plant, with annual capacity of 3,000 tons of powders of copper, brass, bronze, tin, and other metals [2].
Approximately 3 million tons of rare earth elements reserves have been determined in Mongolia, which accounts for 2.5% of the world's reserves. It is necessary to approve and implement the "Rare Earth Elements" National Program in Mongolia [3].
In the future, the rapid development of the modern industries in the form of "Coal-chemical complex", “Steel production complex”, and “Metallurgical complex” megaprojects as well as “Science and industrial parks” based on the global market is the effective and the progressive in many ways.

The industrial sector “metal production” is still one of the biggest emitters of fossil based anthropogenic carbon dioxide. While carbon carriers are often used as source of energy, also the chemical process, the reduction, in many cases requires carbon. [1] Examples are various shaft furnace technologies, rotary kilns, rotary hearth furnaces etc. Especially iron industry as well as zinc and copper recycling, lead and tin metallurgy and others consume huge amounts of carbon for reduction. Fresh biomass contains far too many volatiles and does not offer appropriate mechanical properties. Also standard pyrolysis produces a type of charcoal, which is still too reactive because of remaining volatiles and high porosity. The Chair of Nonferrous Metallurgy, Montanuniversitaet Leoben, has started to develop special charcoals out of various types of wood based biomass that offer characteristics which are closer to the one of metallurgical coke than common charcoals. These reducing agents were tested for zinc recycling in rotary kilns as well as in molten slags for other recycling processes. The tests done in lab- and technical scale showed promising results regarding a possible replacement of fossil carbon carriers by special pyrolyzed biomass. The paper describes advantages and disadvantages of the utilization of biomass in the above mentioned field. Furthermore, availability and differences in the quality of wooden biomass with focus on metallurgical application is discussed as well as the utilization of the generated pyrolysis gas [2, 3]. In general, it can be summarized that the use of special pyrolyzed biomass as reducing agent for different metallurgical processes is possible from the technical point of view and can contribute to minimize the CO2-emission from fossil carbon carriers. Especially in times of high CO2-credit prices such concepts for metal production can be also realized economically.

Mining with backfill has been used extensively in underground metal mines which is an important way to conduct the green and low-carbon mining operation. Backfill technologies can achieve both the maximum recovery ratio of underground mineral resources and the environment friendly disposal of mining wastes. This paper systematically reviews the recent development of mining with backfill methods, and the new technology application progresses were introduced from three aspects: high-efficiency and large-scale mining with backfill, continuous mining with backfill methods and how to reduce backfill costs in underground mining. Then the evolution and development of the mining technologies with backfill used in metal mine were introduced. The application and development trends of the whole process of backfill technology covering the preparation and transportation of tailings slurry, barricades design and the drainage of backfill slurry in the stope were analyzed. The mechanism of heterogeneous characteristics and self-weight consolidation behavior of tailings backfill slurry were analyzed, and comparisons between the traditional methods used for strength require-ment design of the backfill structure and the improved strength calculation-design methods for backfill in mine stopes were made. In addition, the in-situ monitoring methods of the backfill slurry to assess the field backfill quality were introduced. Based on the above research, it was obtained that the revolution of mining with backfill methods was the crucial path to achieve high-efficiency, large-scale and low-cost underground mining. The innovations on key points in the whole process of mine backfill were necessary measures for the stable preparation and utilization of high-quality underground backfill slurry. Most importantly, an in-depth study on the backfill mechanics of different mining methods was essential to ensure a safe, green, economical, and convenient application of mining with backfill. In the end, the research aspects and directions that should be focused on in the future were clarified. And the brief statement that accelerating the development of new technologies, new materials and new equipment for green and low-carbon backfill was the driving forces to promote the transformation and development of mine backfill was given.

Gipronickel Institute LLC, forming part of Norilsk Nickel MMC PJSC, has developed and patented the solid household and industrial waste management process based on the extensively used Vanukov furnace smelting technology. The process ensures complete destruction of poisonous and toxic compounds as a result of smelting in the actively stirred melt due to high temperatures exposure, the use of oxygen blast and rapid gas cooling. The following can be processed using this technology: stored unsorted solid domestic waste, newly formed unsorted solid household waste, organic part of sorted solid household waste, industrial waste, including chemical waste, and chemical warfare agents. The report presents a comparative analysis of the suggested method with familiar solid waste management processes, outcomes of new process technology pilot testing, and basic technical solutions for project implementation.

The assembled 3D and 4D computer models of T-x-y and T-x-y-z diagrams permit to verify and validate the data on phase equilibria and to design the microstructures of heterogeneous material, including the materials genome decoding. “Phase Diagram (PD) as a Tool of Materials Science”, http://ipms.bscnet.ru/labs/skkm.html , is focused on the following topics: concentration fields of different dimension with the different solidification schemes and microstructures, correction of PD graphics, multi-component systems polyhedration, 3- and 4-phase regions with the reaction type changing, competition of crystals with different dispersion in the invariant regrouping of masses, mathematical approximation of PD, assembling of PD computer models, 3D prototyping of the phase regions and concentration simplexes for the exploded PD and for the concentration complexes of the reciprocal quaternary systems, simulation of DTA spectra and X-ray analysis spectra in the training programs for specialists in the field of physics-chemical analysis. Computer models of PD are the wonderful addition for the thermodynamicaly assessed experimental PD.
This work was been performed under the program of fundamental research SB RAS (project 0270-2021-0002).

Municipal solid waste incineration (MSWI) is a widely implemented waste management option. Although MSWI reduces waste volume by 90%, it generates considerable incinerator residues, namely, bottom ash and fly ash – the latter posing a greater challenge on account of containing leachable heavy metals, chlorides, and organic contaminant. On the other hand, the bulk of the fly ash’s composition makes it a rich mineral source for silica and lime, and potentially well suited as a raw meal in cement production. This paper presents a study on the feasibility of making green cement using three of the incinerator by-products: incinerator heat, residue ashes and carbon dioxide. The green cement can be synthesized exclusively with incinerator residues at incinerator heat temperature of 1000°C. The cement paste is then activated by carbon dioxide to produce strength. Municipal solid waste incineration can be turned into a green cement production. Paste compacts prepared from this material displayed a high CO2 reactivity, achieving an average compressive strength of 53 MPa and an average CO2 uptake of 6.7 wt. % after only 2 hours of carbonation activation at 1.5 bar. QXRD and QEMSCAN results identified the reactive phases to be chloro-ellestadite (Ca10(SiO4)3(SO4)3Cl2) and γ-C2S, which, upon CO2 activation, formed a binding matrix comprised of gypsum, calcium-carbonate precipitates, and a Ca-Si intermix. Leaching tests deem this cement non-hazardous as the monitored heavy metal concentrations in the leachate were well below regulatory limits. Concrete specimens prepared from the cement displayed comparable performance to Portland cement concrete, while additionally demonstrating a viable approach for waste utilization, carbon emission reduction, and natural resource preservation.

In recent years, the “greening” of cement and concrete has taken on a different path with a sharper focus on reducing carbon footprint while enabling companies and countries to benefit from carbon credits. It is only in 2012 that the first academic paper on the use of biochar – the solid by-product of pyrolysis or gasification – was published. In the following 9 years, biochar concrete has taken an upward trajectory in terms of academic research and commercial consideration. Two of the key reasons accounting for this popularity are that biochar is potentially a carbon negative material from the life-cycle accounting perspective [1], and that biochar is a widely available material that has primarily been used in agriculture (for soil enhancement) and for water purification.
This talk aims to demystify the near-decade long development of this young field of research, and summarize the key milestones in the growth path of this sustainable construction material. The different technical ideas and scientific technique used to achieve these milestones will be elaborated. For example, it was found that coating polypropylene fibers with biochar, and deploying these fibers to reinforce mortar, decreases water sorptivity of the mortar by about 44%, and water penetration by about 62%. Correspondingly, it increases 7-day and 28-day compressive strength by about 11% and 4.3% respectively [2]. When biochar was deployed evenly in the mortar mix without any fibers, biochar reduces water penetration by about 58.8% and increases 7-day compressive strength by about 13.8% [3]. Methods used for these studies include ASTM C1585-04 (Standard Test Method for Measurement of Rate of Absorption of Water by Hydraulic-Cement Concretes) and different characterization methods, such as Fourier Transform Infrared analysis for studying the surface chemical species found on biochar, and Brunauer-Emmett-Teller method for measuring pore size distribution of mortar samples containing different quantities of biochar.
These efforts have created several important areas of research, including the potential of using biochar as a mean of enhancing accelerated carbonation curing of concrete; that is, using biochar to increase the total amount of CO₂ that can be removed from the atmosphere through the process of carbonation of the calcium hydroxide and calcium silicate hydrate found in curing mortar mixture [4]. Latest evidence for the effectiveness of specially made biochar in improving electromagnetic wave (GHz) shielding of mortar tiles and application of biochar concrete under extreme environmental conditions (for example, using biochar to reduce the infusion of sulfate and chloride ions into mortar submerged in aqueous medium [5], and for increasing the “crack-resistance” of concrete operating under high temperature [6]) will also be presented.
This talk will end by boldly charting the future directions of biochar concrete and how it can continue to stay abreast and relevant, by addressing some of the most challenging sustainability-related problems facing the construction industry the world over.

3D computer models for T-x-y diagrams of real systems FeO-SiO2-Fe2O3 and Mg2SiO4-CaAl2Si2O8-SiO2 and for their prototypes (with the expanded borders between the phase regions) have been elaborated [1-4]. Afterwards the 3D-puzzles of the exploded phase diagrams (PD) with the phase regions and with the clusters of phase regions as its elements have been printed. When preparing the technical specifications for the phase regions prototyping, the peculiarities of each region or the regions clusters have been thoroughly explained.
The T–x–y computer model for pseudo-ternary system Mg2SiO4–CaAl2Si2O8–SiO2 contains the immiscibility surface, five liquidus surfaces, 23 ruled surfaces, 4 horizontal complexes at the temperatures of invariant points, 20 phase regions. The calculation of crystallization paths was carried out. Using the diagrams of vertical and horizontal mass balances permit to analyze the crystallization stages and obtain the sets of microconstituents for the given mass centers.
The assembly of 3D model of phase diagram is the final stage of its study by the methods of thermal analysis and X-ray diffraction, and the correction of curvature of curves and surfaces in agreement with the thermodynamic parameters of components and new compounds. If there is the contradictory data, then different variants of PD are assembled. The PD computer model permits to compile the scheme of equilibrium crystallization in the concentration fields of various dimensions (point, line (curve) fragment and fragment of the concentration triangle plane) formed during orthogonal projection of all PD surfaces. This procedure is the main step in decoding the genotype of a heterogeneous material. The concentration fields with unique sets of micro-constituents are revealed as a result of calculation of the qualitative and quantitative composition of microstructure elements. In this case, a list of concentration fields with micro-constituents, which does not differ from the microconstituents of neighboring fields of smaller or the same dimension is compiled.
Analysis of two variants of FeO-SiO2-Fe2O3 PD showed that the presence of immiscibility surface of two melts does not affect the micro-constituents set of the heterogeneous ceramic materials of this system. In the case of application of the ultrafast cooling technology of initial melt and its heterogeneous states at various stages of crystallization, the final set of formed materials can be significantly expanded.
This work was been performed under the program of fundamental research SB RAS (project 0270-2021-0002) and it was partially supported by the RFBR project 19-38-90035.

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