Redox-active polymers with electrochemical reversibility and rapid electrode reaction rates are employed to develop organic electrode-active materials employed in organic batteries, based on their selfexchange reactions in polymer layers. Negative charging of the electroneutral redox polymers results in a significant increase in basicity to allow protonation of each redox-active site in the polymer. Since most of the hydrogenated products are no longer redox-active, aprotic battery electrolytes are employed to avoid the hydrogenation in organic batteries. On the other hand, organic compounds that undergo reversible hydrogenation, such as toluene to yield methylcyclohexane, have been studied as hydrogen storage materials. However, the hydrogenation with hydrogen gas usually proceeds via a highly energy consuming process. We anticipated that electrolytic hydrogenation of the redox-active molecules would provide a much simpler process. We have found that ketone-containing polymers stored hydrogen via the electrolytic process in the presence of water at room temperature. The resulting alcohol polymer evolved hydrogen gas by warming under mild conditions with an iridium catalyst. The hydrogenation/dehydrogenation cycle was accomplished throughout the polymer layer, meaning that all of the ketone groups in the polymer were equilibrated with the hydrogen gas according to > C = O + H₂ ⇄ > CH-OH in the presence of the iridium catalyst. The reversible hydrogenation/dehydrogenation was extended to various types of organic groups in the polymer, providing many types of the hydrogen carrier polymers as a new class of energy-related functional polymers. The easy handling and moldable nature of the organic polymers indicate the feasibility of applying them as pocketable hydrogen carriers.

Epochs of human civilization are marked by the sources of materials used at the periods, namely: Stone Age, Bronze Age, Iron Age and Silicon Age. The materials used at these eras were mined and can be linked to the development of mining for the benefit of society. The same epochs are indications of advances in Materials Science and Engineering. We are now in the Smart or Intelligent Materials age. One of the key drivers of the Smart Materials era is sustainable development. To achieve sustainable development, the G8 countries agreed on the 3R Initiative at the Sea Island Summit in June 2004 that was launched at the Ministerial Conference in Tokyo in 2005. The 3Rs concept for sustainable development refers to Reduce, Reuse and Recycle and it is now extended to 4Rs to include “Recover”. There is potential to further extend the 4Rs concept to 5Rs to include Reprocess. Achieving the objectives of 5Rs within the Sustainable Development Goals of the United Nations involves a critical look at how renewable energy and Smart or Intelligent materials are developed. A critical source of Smart materials and renewable energy resources is mining. Unfortunately, mining is now considered intolerable and antagonistic to sustainable development in the context of environmental friendliness and its contribution to fossil fuel use consequences. Intelligent mining ensures sustainable resource recovery and processing and will make critical materials availability for Smart materials and renewable energy development. Regrettably, mining currently faces aggressive challenges with a bleak future in accomplishing these objectives.

For the past 5 years, Montana Tech has coordinated eff orts with Chevron Phillips Chemical to determine how the organic depressant, disodium carboxymethyl trithiocarbonate (Orfom^® D8 depressant), works to separate chalcopyrite from molybdenite during cleaner flotation of a bulk sulfide concentrate. Pure minerals were studied by cyclic voltammetry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, zeta potential and adsorption density. Results illustrated that Orfom^® D8 was specific for chalcopyrite by chemisorbing electrochemically through its thiol functionality (CSS^-) thereby allowing the carboxylate group (COO^-) to extend into solution and cause depression. Density Function Theory via molecular orbital modeling corroborated the results. Flotation results obtained with Orfom^® D8 using laboratory simple kinetic tests (SKT), bench-scale experiments, and industrial plant trials revealed grade and recovery of both Cu and Mo were better than those obtained with the most common inorganic depressant, NaSH. Replacing NaSH with Orfom^® D8 in Cu-Mo flotation is therefore recommended and would simultaneously address mining sustainability issues.

Cyclodextrins (CDs) are well-known macrocyclic compounds in the fields of supramolecular and molecular recognition. For use as separation and adsorption materials, the water-soluble CDs must be modified into solid forms. Hybrid polymers consisting of amorphous silica and modified α- or β-CDs (propyl-modified α-CD, butyl-modified β-CD, and ethylenediamine modified-βCD), designated as propyl-α-CDP (2), butyl-β-CDP (3), and EDA-β-CDP (4), respectively, were prepared, and their adsorption capacities for CO₂, CH₄, and H₂ were evaluated. The α-CDP (1), which was derived from α-CD shows no adsorption capability for all gases examined. On the other hand, compound 2 exhibited the maximum CO₂ adsorption of about 18.0 ml at ～500 kPa. Compound 4 adsorbed the maximum amounts of CH₄ and H₂ (about 7.5 and 4.0 ml, respectively). In contrast, the 3 demonstrated almost no adsorption capability for CH₄ or H₂ molecules, adsorbing only CO₂ gas.

Ag nanofiber (NF)-based networks have attracted significant attention as next-generation flexible conductive materials. Ag NFs with high aspect ratios decrease the number density required for percolation; hence, they form qualitatively superior conductive films. Previously, we developed a novel method for fabricating Ag NFs via Pt nanoparticle-assisted hydrogen-free reduction of Ag⁺- containing polymers. This method enables rapid preparation of Ag NFs in high yields. Electrospinning was utilized for producing Ag⁺containing precursor NFs. Nevertheless, it was diffi cult to achieve Ag NFs with high aspect ratios due to fiber discontinuity resulting from the limited amount of Ag⁺ in the electrospinning solution. In this study, in order to improve the previous method, highly concentrated AgNO₃-containing polymer NFs were produced using solution blowspinning instead of electrospinning. Ag NFs with ultrahigh aspect ratios of over 10⁵ were fabricated via catalytic reduction of solution blowspun AgNO₃-containing polymer NFs. Ag NF networks with low sheet resistance were produced, thereby demonstrating their potential applicability as flexible transparent electrodes and transparent film heaters.

The Zone 5 Cu-Ag deposit is the most consistently (for ～4.2 km) mineralized deposit in the Khoemacau district in northwestern Botswana, with an underground mineable resource of ～100 Mt grading 2 % Cu and 21 g/t Ag. The deposit consists of a redox-buffered metal-zoned ore body hosted preferentially by chemically reduced meta-sediments overlying oxidized hematite-bearing arkosic sandstone. Ore-grade mineralization is typically hosted in variably deformed quartz-calcite veins, along metamorphic cleavage, along bedding, in shear fabric, and in folds. Geochemical assay data established during exploration indicates widespread signifi cant concentrations of Ag, correlating positively with Cu. In this study, we apply a Bruker M4 TORNADO micro-X-ray fluorescence (μXRF) scanner for multi-element mapping in selected highgrade drill core samples, with particular focus on Ag partitioning. Collection of μXRF data was followed by microscopic and SEM-EDS observations to validate results. The μXRF data coupled with petrographic results indicate: i) μXRF multi-elemental mapping on the Zone 5 drill core samples was very eff ective and can be applied as a fi rst order geochemical analytical tool for characterizing mineralization and targeting important sections of the core, ii) silicification contributed to cleavage formation, which later became important ore trap site, and iii) Ag is closely associated with Cu and Fe. SEM-EDS results show that native silver and stromeyerite in part co-precipitated with hematite post Cu-(Fe)-sulfi de deposition.

In the present work, the fine grinding of limestone was performed by using a super centrifugal mill (SC-mill), a type of bead mill. The feed sample contained limestone particles below 75 μm in size ground by a crusher mill with a feed slurry density of 30 mass%. The eff ects of operational grinding conditions in the bead mill including rotor speed, grinding time, grinding bead size, and mass of the grinding beads on the fine grindability of limestone were investigated, as well as the wear of the grinding beads. The fine grindability was evaluated through the mass of products below 1 μm measured using laser diff raction and scattering. The bead wear was investigated through the mass loss of zirconia beads measured using inductively coupled plasma mass spectrometry. In the results, the mass of the fine products and bead wear were found to be proportionally related, and expressed as a function of the operational grinding conditions.

Aiming to suppress global warming, Japan has set a goal of reducing CO₂ emissions to zero by 2050. In order to achieve this goal, production of hydrogen from renewable energy by water electrolysis and obtaining electrical energy from fuel cells is regarded as an important system. Although polymer electrolyte fuel cell (PEFC) systems has already commercialized for home and fuel cell vehicles, their high cost due to the use of Pt as electrode catalysts has hindered their widespread use. Therefore, in this study, we synthesized molybdenum nitride and investigated the oxygen reduction activity with the aim of developing a Pt-free cathode catalyst. First, molybdenum nitride was obtained by calcining molybdenum sulfide under NH₃ flow. As a result, Mo₅O₆ obtained by calcination at 750°C showed the highest oxygen reduction activity. Next, (NH₄)₆Mo₇O₂₄·4H₂O which contains nitrogen was calcined under NH₃ flow to prepare molybdenum nitride. Then, MoN calcined at 800°C showed higher oxygen reduction activity than any molybdenum nitride. Since Mo is much cheaper than Pt, Mo nitrides made from (NH₄)₆Mo₇O₂₄·4H₂O are considered to be useful as cathode catalysts for fuel cells.

This study aimed at elucidating the effect of annealing on the positive temperature coefficient characteristics of polyethylene/carbon black (PE/CB) composites. The PE/CB composite was annealed at 140, 150 or 160°C, and the temperature-dependence of its resistance was measured. The internal morphologies of the PE/CB composites with different annealing temperatures were observed using a scanning electron microscope, to verify the optimum annealing conditions for obtaining highly reproducible temperature dependence of resistance. It was shown that the resistance in the PE/CB composite increased with the percentage of inside cracks, which was closely related to the reproducibility of the temperature dependence. Finally, the optimum annealing temperature for the targeted PE/CB composite was estimated to be 150°C.

In this study, a combined process consisting of salt roasting and acid leaching was conducted to recover copper per sulphide concentrate with 43.5% of chalcopyrite. The chalcopyrite concentrate was roasted in the absence and the presence of potassium chloride (mass ratio of concentrate:KCl from 1:0.5 to 1:0.9) at various temperatures (400-600°C) and different roasting times (1-4 hours) under air atmosphere. The roasted concentrate was dissolved in sulphuric acid solution (60 g/L) with a solid-liquid ratio of 1:8 at an ambient temperature for 2 hours. The chalcopyrite concentrate, roasted samples, and leached residues were analyzed using atomic absorption spectrometry, UV-VIS spectrophotometer, and X-ray diffractometer. Thermogravimetry and differential thermal analyses were applied on the chalcopyrite concentrate and the concentrate with KCl up to 1000°C. Results showed that about 80% and 90% of chalcopyrite decomposed under the conditions with the copper concentrate:KCl ratio of 1:0.6, roasting time of 2 hours at 500°C and 550°C, respectively. The DTA-TG analyses revealed variant phase regions associated with chalcopyrite decomposition through the roasting. Copper dissolution with the sulphuric acid solution from the roasted concentrates was over 99.7% and 99.0% under the determined conditions. The thermodynamic stability of chalcopyrite with KCl was discussed by calculating Gibb's free energy.

Fast data transmission is becoming a key parameter in mine planning, operation, and safety. Therefore WSNs (wireless sensor networks) is taking a leading role in underground mine environment communication.WSNs can measure mine environmental parameters by sensors to provide quick and detailed communication for comprehensive assessment of the situation, during both regular operations and emergency situations.Nowadays, WSNs are developing very fast, getting more compact, energy and cost-efficient. On the other hand, underground mines have very specific working conditions characterized by narrow spaces, dynamic environments, and high humidity. This demands WSN nodes to be specifi cally arranged to be functioning efficiently considering limited throughput and energy resources. Wi-Fi Direct is a wireless connection type used in WSN and supported by many manufacturers around the world. This research will consider using Wi-Fi Direct and ad hoc networks for WSN and will analyze the deployment of WSN nodes in underground mine environments. The physical experiment measuring the performance of deterministic Wi-Fi Direct mode node deployment in Osarizawa experimental underground mine was conducted. The experiment indicated that the data packets can be sent without loss to a distance up to a 140 m in a straight tunnel with 4 m² crosssection area. The obtained results were applied to planned WSN node deployment at Tishinskiy mine site in East Kazakhstan.

In this study, polyvinyl chloride (PVC) was pyrolyzed with sodium hydroxide (NaOH) to capture the generated hydrogen chloride (HCl) gas as sodium chloride (NaCl) and carbonize the organic contents to generate fuel gases such as hydrogen (H₂) and methane (CH₄). In addition, the pyrolysis behavior of PVC with NaOH, and its application to copper recovery from thin PVC-coated tinned copper multiwire cables were examined. With an increase in temperature, the PVC released HCl gas at approximately 300°C and underwent carbonization to generate fuel gases at approximately 500°C. Upon immersing the PVC in a NaOH solution, it was converted into a powdered carbonaceous material; therefore, the amount of HCl gas decreased by being captured as NaCl, whereas the amount of fuel gases generated increased by pyrolysis. At a heating temperature of 500°C, the PVC coating of the tinned copper wire was removed via the formation of a carbonaceous material and sodium salts after the addition of distilled water. The results suggest that this environmentally friendly and eff ective process for capturing HCl gas as NaCl and converting the covered PVC into carbonaceous materials and fuel gases is suitable for PVC treatment, and the proposed approach can be applied to copper recovery from multiwire tinned copper cables through pyrolysis with NaOH.

This paper proposes a method to estimate the particle (rock) size distribution of a muckpile using Deep Learning based on 3D shape information given by 3D photogrammetry. Optimization of blasting is crucial to increase the productivity of mining operations. However, since the internal structure of the ground (bedrock) is usually unknown, it is difficult to set the appropriate parameters, amounts of explosives, blasting location and timing. In order to solve the problem, research has been carried out to design and analyze the blasting procedures by measuring the particle size distribution after the blast. Ordinary works focus on developing accurate measurement methods of particle size distribution for the analysis. We aim to increase the measurement accuracy by combining 3D photogrammetry and Deep Learning for 3D shape data. The 3D muckpile model is generated using Structure from Motion (SfM), which is a reconstruction method that can generate 3D point clouds of the target object from multi-view images. The particle size distribution of muckpiles is estimated by using Deep Learning. The proposed network consists of “Local Module” that learns the local shape of rock and “Global Module” that learns the shape of the entire muckpile. From the experiments, it can be said that the fragmentation of the actual muckpiles can be effectively estimated by using the proposed method.

Carbon fiber reinforced plastic (CFRP) is a composite material made of carbon fibers and resin, and is widely used because of its light weight, corrosion resistance, and durability. However, its excellent properties make it difficult to recycle, and most of the CFRP waste is landfilled. A new recycling technology to recover the carbon fiber from waste CFRP is desired. In this study, a new method to decompose the resin part by heating waste CFRP with sodium hydroxide (NaOH) to recover the carbon fibers with high strength was investigated. Waste CFRP was heated with NaOH under nitrogen atmosphere at 200-600℃ for 0-90 min, then washed with distilled water, and sieved to recover the high- strength carbon fiber. By heating without NaOH, it is diffi cult to separate the fiber from resin. By heating with NaOH, carbon fiber with high strength can be recovered at 250-350℃ by hydrolysis reaction of resin with NaOH and distilled water, while those with low strength at higher than 400℃, due to the pyrolysis reaction of resin and carbon fiber. By immersing the CFRP into NaOH at 300℃, long length carbon fiber with high strength can be recovered.

Gold is used in various fields and is a rare resource in nature. Recovery of gold from domestic wastes is desired in Japan. Bamboo is an abundant biomass resource in Japan, and the promotion of its utilization is desired. In our previous studies, sulfur-impregnated carbonaceous adsorbent with high heavy metal removal has been prepared from biomass resources using sulfur with a high affinity for heavy metals. In this study, sulfur-impregnated carbonaceous bamboo was prepared from bamboo powder by pyrolyzing at 800°C with sulfur under N₂ atmosphere for recovering gold from strong acidic solution. Gold could be recovered from strong acidic solution by precipitation of gold metals on the surface of sulfur-impregnated carbonaceous bamboo, while little amount of gold was recovered using raw bamboo powder and non-sulfur-impregnated carbonaceous bamboo. The adsorption and reduction reaction of gold on the surface of sulfur-impregnated carbonaceous bamboo occurred rapidly, and it was observed that gold particles were larger as the reaction time increased. Gold was precipitated as smaller particles on the surface of sulfur-impregnated carbonaceous bamboo than those on the surface of activated carbon.

In this study, we aim to prepare a highly selective fluorine adsorbent by mechanochemical treatment from two types of titanium oxides, rutile and anatase. Fluorine adsorption of the products from rutile and anatase by mechanochemical treatment increased for 60 min regardless of the ball diameter used in mechanochemical treatment, and fluorine adsorption of the products from rutile and anatase were 1.5 and 2.0 times higher than those of raw materials, respectively. With decreasing pH to 2-3, fluorine adsorption on products increased to the maximum at pH 2-3. The products can remove fluoride ion in seawater at pH 2, and fluorine adsorption behavior followed Langmuir model better than Freundlich model. Maximum adsorption amount of fluoride ion by products from rutile and anatase were 0.096 and 0.125 mmol/g, respectively. Regardless of the temperature the adsorption rates of products from rutile and anatase follow the pseudo-second order kinetic model than the pseudo-first order kinetics model. The adsorption on the products from rutile and anatase are the endothermic nature of the adsorption process and spontaneous reaction.

The adoption of hyperspectral imaging has had positive feedback in multiple industries, especially those heavily reliant on the visual analysis of subjects. Reasons for such are primarily due to the high accuracies achievable from processing high dimensional data. Nevertheless, hyperspectral data is said to possess a ‘dimensionality curse’. This phenomenon, deems it computationally demanding and difficult to employ in rapid field investigations such as the use of drone-mounted spectral cameras to distinguish rocks. To counter this, this study proposes the employment of a method of reducing the number of dimensions used to highlight the most characteristic feature bands referred to as Neighbourhood Component Analysis(NCA). NCA aided in disregarding redundant bands from 204 dimensionalities, to a still highly capable 5 bands dimensionality, which coincides with the current production of 5-band detection drones. To process this data, several machine learning(ML) algorithms were run in order to perform spectral classification of rocks based on the 5 NCA defined bands. This study’s novel findings show that one is able to acquire with NCA and ML, 5 bands, with a post-optimization average global accuracy of 95.4%. Such capabilities are highly sufficient considering the magnitude of the dimensionality reduction combined with the potential field drone applicability.

An earthquake-triggered landslide often generates the high-water content sludge due to excessive rainfall intensity. In general, the sludge is disposed of in the dumping area. Meanwhile, Indonesia is known as a leading country for the palm oil plantation. The production, however, remains the agricultural waste, socalled Empty Fruit Bunch (EFB). EFB contains the fibrous material which is perceived to absorb the water. In this work, instead of proceeding with the sludge removal, the recycling is proposed by applying the Fiber-Cement Stabilized Soil (FCSS) method. FCSS method is a soil recycling method that performs the mixing condition of the sludge, cement, and fiber material. Moreover, the EFB is used as the fiber material. The mixing condition is designed with various amounts of each material to investigate the mechanical properties of the sludge reinforced by EFB. Thus, the Unconfined Compression Strength (UCS) test and permeability test are conducted.

This paper describes the piezoelectric properties of LiM-doped (M = V, Nb, Ta, or Zr) aluminum nitride ((Li_yM_1-y)_xAl_1-xN) films with respect to the composition ratio of Li and M. Films of (Li_yM_1-y)_xAl_1-xN were prepared by a radio frequency magnetron sputtering method and characterized by crystal structure, as well as electrical properties such as the piezoelectric coefficient d₃₃ and resistivity ρ. The films for M = Nb with x = 0.13-0.20 and y = 0.41-0.49 showed |d₃₃| = 8.26-9.54 pC/N, which were 21-38% larger than non-doped AlN. On the other hand, the films for M = V, Ta, and Zr exhibited a decrease in piezoelectricity. The piezoelectric properties in (Li_yM_1-y)_xAl_1-xN films against M can be mainly explained by the combination of the following factors: crystallinity, lattice parameter ratio c/a, ρ, orientation degree, and polarity inversion. This study revealed that the composition ratio of Li and M gives (Li_yM_1-y)_xAl_1-xN films different behaviors on physical properties and the films for M = Nb with similar stoichiometric compositions (y～0.5) are promising candidates as piezoelectric materials for micro-electro-mechanical systems.

In this paper, the removal processes for silicon (Si), aluminum (Al) and phosphorus (P) impurities from low-grade iron ore, in which hematite (Fe₂O₃), goethite (FeO(OH)), and quartz (SiO₂) are the main mineral constituents, have been presented. The reverse froth flotation process was applied to remove silicon and aluminum impurities from the iron ore using dodecyltrimethylammonium bromide (DTAB) and dodecylamine acetate (DAA) cationic collectors at a broad slurry pH ranging from 2 to 12. Whereas alkaline roasting followed by a water washing process was employed to remove phosphorus impurity from the iron ore under the various sodium hydroxide concentrations, different roasting temperatures, and prolonged varying times. Results showed that the maximum removal rate of SiO₂ and Al₂O₃ achieved were 58.3% and 31.0% via reverse froth flotation using DTAB collector at pH 12, whereas 38.7% SiO₂ and 10.0% Al₂O₃ with DAA collector. The level of total (SiO₂+Al₂O₃) impurities in the tailing as iron ore product from the reverse flotation was reduced from 7.4 mass% to 4.4 mass% as the initial level. On the other hand, about 61% of phosphorus in the iron ore was removed by the combined alkaline roasting and water washing at the conditions optimized as 50 g/kg-ore NaOH at 300°C for 0.5 h. The grade of phosphorus impurity reached 0.04 mass% from 0.09 mass% (initial grade). Simultaneously, the iron grade and level of SiO₂+Al₂O₃ impurity in the iron ore product from reverse flotation of the low-grade iron ore with DTAB collector reached 60.0 mass% and 4.4 mass%, which are acceptable levels for ironmaking.

Recent technological advancements are raising the demand for valuable and critical metals. In a quest to find new resources, cobalt-rich ferromanganese crust (CRFC) is considered as a new alternative since it contains various valuable metals, including cobalt (Co), nickel (Ni), and manganese (Mn). The aim of this work was to investigate the efficiency of (1) the enhanced gravity separation by the Falcon concentrator and (2) the reverse flotation to enrich valuable metals from CRFC. The main finding of this research was that Mn, Co, and Ni could be enriched by combining the enhanced gravity separation and the reverse flotation after carefully controlling the particle size of the sample.

Passivation behavior of high silver containing copper anodes was investigated using slowly cooled Cu- 1%Ag anodes of different lead (Pb) concentrations. The addition of Pb distributes silver in the Pb phase and reduces the amount of silver that is solidly soluble in copper and, thus, generates a fine silver powder on the anode surface which is a main contributing factor of passivation. Electrorefining experiments were conducted using a synthetic electrolyte containing 40 g/L Cu²⁺ and 180 g/L H₂SO₄, at 60°C. SEM-EDS analysis was used to study the resulting anode slime and showed that increasing Pb content altered the anode slime structure from fine and compact to porous and less adherent to the anode surface. Utilizing a Cu-1%Ag0.2%Pb anode yielded the longest passivation time with a low and stable cell voltage of 0.1V. The slime morphology was characterized by precipitated metallic silver particles either as inclusion or loosely present on the surface of the abundant complex Cu-Ag-Pb sulfate type of compounds. Because of the economic importance of silver recovery from the anode slime, understanding its behavior during electrorefining will enable operating with high impurity anodes especially in secondary copper processing where metallic impurities can result from e-waste and copper alloy scrap.

Blast furnace (BF) slag, one of the by-products of iron- and steel-making plants, was converted into the product including hydrogarnet using the alkali fusion method for HCl gas removal. The slag with diameters of less than 2 mm was transformed into the alkali-fused slag with reactive phases via alkali fusion using sodium hydroxide at 600°C for 6 h, after which the fused slag was added to distilled water and stirred at room temperature to prepare the precursor to synthesize the product including a hydrogarnet by heating at 80-160°C. The product could remove HCl gas at high temperature (800°C), and Cl fixation in the product follows the pseudo-first-order kinetics model rather than the pseudo-second-order kinetics model. These results suggest that a novel product able to remove HCl gas at high temperature can be synthesized from BF slag via alkali fusion.