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The operating parameters of high-pressure grinding roller (HPGR) is commonly obtained from a crushing test using small or semi-industrial HPGR. However, a large ore sample size is required, and the test is complex, hence the uptake of HPGR technology has been slow. A static pressure work index based on Bond’s third theory of comminution is proposed to determine the specific energy consumption of particle bed comminution of ore using an HPGR. A piston ballast test (PBT) has been conducted, and an equation established to predict the work index for three ore types, which can be subsequently used to estimate the HPGR circuit-specific energy consumption. The model has an error of 5.59%. This paper provides an experimental approach for determining the energy consumption and performance of an HPGR suitable for research and application.

This study has developed an efficient low-temperature resistant quartz collector, named KDB. The effect of KDB and the conventional collector sodium oleate (NaOL) on the reverse flotation behavior of hematite was investigated by flotation tests on pure minerals and binary mixed ores. On this basis, adsorption thermodynamics, surface tension determination, surface contact angle determination, and Fourier-transform infrared spectroscopy (FTIR) analysis were used to investigate the interaction mechanism of the two collectors at different temperatures. The results showed that both can enhance hematite reverse flotation at room temperature, and that the collection performance of KDB is stronger than that of NaOL. At low temperatures, the collection performance of KDB still obtained better flotation indices compared with NaOL. The binary mixed ore flotation test showed that, at 15°C, the grade and recovery with KDB as the collector was improved by 10.77% and 14.32% compared with those of NaOL, respectively. The contact angle of the quartz surface under the KDB system at 15°C is 55.56° higher than that of NaOL. The FTIR analysis showed that KDB can significantly enhance the hydrophobicity of quartz, and that the adsorption strength on the quartz surface at low temperatures is much higher than that of NaOL.

The lifespan of refractory linings is a major industrial concern for safety, on-line availability, and financial reasons. In copper smelting, batchwise operating matte converters are the furnaces that pose the greatest challenge when it comes to refractory wear and lining life. In this work, the structure and morphology of used magnesia–chrome bricks were studied using X-ray computed tomography and mineralogical techniques. The bricks were taken from various locations of an end-of-life brick lining of an industrial Peirce–Smith converter, after a normal campaign at Boliden Harjavalta smelter (Finland). The results show that it is possible to visualize in 3D, e.g., porosity, metal-containing phases, and refractory magnesia in the used bricks. Different digital images, such as cross-sections and average volume fractions, were used as a non-destructive method to characterize the bricks’ internal structure. The metal/matte infiltration in the open porosity was found to differ based on the location in the converter, with some bricks having no metal/matte infiltration and the tuyere line showing metal/matte infiltration at a depth of about 100 mm from the hot face.

The employment of ANSYS finite element analysis software facilitated the examination of temperature and stress distributions within FeMnSiCrNi shape memory alloy coatings subjected to single-pass and multi-pass laser alloying. The findings from the simulation demonstrated that the fusion zone in the track created by a single laser pass adopts a semi-spoon configuration with a circular area at its center. Following the alloyed coating's return to ambient temperature, the core region of the substrate experiences a transition in transverse residual stress, starting with compressive stress at the center and gradually shifting to tensile stress towards the edges. In the direction of laser movement, the longitudinal residual stress within the coating undergoes a pattern of changing from compressive to tensile, and then back to compressive stress. During the multi-pass laser alloying process for FeMnSi shape memory alloys, the procedure mimics sequential heating phases, peaking at a temperature of 2467°C.

A combined hydrometallurgical and pyrometallurgical process is proposed for the treatment of jarosite residue from zinc hydrometallurgy. The main steps of the proposed process include Ca(OH)₂ leaching for the ammonium component, biomass magnetization roasting, and magnetic separation. The optimal conditions for Ca(OH)₂ leaching were determined as follows: Ca(OH)₂ dosage of 25%, L/S ratio of 15, leaching temperature of 70°C, and leaching time of 60 min, resulting in a 96.27% ammonia jarosite decomposition rate. During the biomass roasting process, with corn cob as the reductant, the biomass at a ratio of 0.75, and roasting at 800°C for 90 min, a reduction rate of 43.61% was achieved. Magnetic separation was then performed, resulting in a magnetic concentrate with an iron grade of 67.56% and iron recovery of 83.20%. SEM-EDS analysis showed reduction products with abundant microcracks and a loose structure. Research on the use of biomass as an alternative reductant for magnetization roasting is of great significance for emission reduction and green production.

The iron-based shape memory alloys have found applications in the pharmaceutical and aerospace industries for their light weight and excellent shape memory effects. The shape memory effects and corrosion properties are significantly influenced by additives and heat treatments. Vacuum arc remelting was employed to prepare Fe-10Mn-6Si-4Ni-7Cr-0.3C-mTi/nNb (m = 0.1, 0.3, 0.5, 0.7, n = 0.05, 0.1, 0.3, 0.5) shape memory alloys. The samples were hot-rolled at 1100°C and solution heat-treated at 1150°C for 1 h. The shape memory effect, microstructure, and corrosion performance of Fe-10Mn-6Si-4Ni-7Cr-0.3C-mTi/nNb were analyzed at higher aging temperatures. The microstructural investigations indicate that large amounts of TiC, NbC, Cr₂₃C₆, and Cr₇C₃ phases are precipitated when aged at 800°C, leading to improvement of the shape memory effect of the alloys. The shape recovery ratio reaches 89.9%, 89.5%, 91.1%, and 74.4% for the alloys with 0.1 Ti, 0.3 Ti, 0.5 Ti, and 0.7Ti additions, respectively, at 800°C aging temperature under 3% bending strain. The aging at 500°C increased the shape memory effect by 20–30%, while further aging at 700°C only improved it by a further 10–20%. The shape recovery ratio of alloys with 0.05 Nb and 0.1 Nb reached a maximum of 88.6% and 88.4%, respectively, when aged at 900°C, while, when aged at 800°C, 0.3 Nb and 0.5 Nb reached 83.7%, and 82.9%, respectively. The shape recovery ratio of the alloys with Nb was increased by about 5–30% compared to that with no Nb. The addition of Ti/nNb and aging at higher temperatures improved the corrosion resistance in 3.5-wt.% NaCl solution owing to the formation of Ti/Nb carbide more easily than Cr carbide, leaving a higher content of Cr in the matrix of the alloys.

The microstructural evolution, mechanical properties, and bio-corrosion behavior of Ti-6Al-4V alloys processed by cold rolling and annealing were investigated to address the need for improved biomedical implants. This study aimed to determine and compare these properties in cold-rolled and annealed cold-rolled SLM-fabricated Ti-6Al-4V specimens. The specimens AMCR01 and AMCR02 revealed elongated grains due to cold rolling and phase compositions of 73% α-Ti and 27% β-Ti in AMCR01, and 87% α-Ti and 13% β-Ti in AMCR02, with inhomogeneous β-Ti clustering. Microhardness tests showed increased hardness in cold-rolled specimens, while tensile tests indicated enhanced strength compared to annealed specimens, which exhibited reduced strength due to grain enlargement. Fractography revealed combined ductile and brittle fracture modes in both conditions. Immersion corrosion tests in SBF solution demonstrated enhanced corrosion resistance with an increased rolling reduction ratio, with annealed specimens showing the lowest corrosion rate. The surface morphology supported these findings, indicating the augmenting effect of cold rolling and annealing on corrosion resistance.

(1 − x)(Bi_0.85La_0.15)FeO₃₋xPbTiO₃(BLF-xPT, x = 0.38, 0.40, 0.415 and 0.43) piezoelectric functional gradient ceramic actuators in disk and bar shapes were fabricated by the tape casting method where the gradient distribution was arranged according to d₃₃. Electric-induced displacement of about 2.38 μm was achieved in the center of the gradient disk actuator along the thickness direction, nearly three times higher than single-component ceramic, with bending displacement of about 17.05 μm occurring at the tip of gradient bar actuator. The simulation of modal analysis and admittance spectrum demonstrated that the bar actuator could produce the bending vibration at 1039 Hz and thus produce enlarged displacement due to the bending deformation of gradient structure. Furthermore, the harmonic response analysis indicated that the maximum stress at the clamped side is of about 344 MPa in the gradient bar actuator under voltage of 220 V at the resonance condition, revealing 12% reduction relative to the bulk bar actuators. Moreover, the lowest stress area at the interfaces between ceramic and metal for gradient bar actuator is relatively larger than that for bulk bar actuators. Our results indicated that gradient piezoelectric actuators with large displacement and low vibration frequency have great potential for underwater acoustic applications.

Lithium sulfide was produced in a plasma system by the reaction of plasma-ionized sulfur with lithium metal. Thermodynamic calculations and optical emission spectroscopy were used to investigate the chemical behavior and reaction mechanism of lithium metal in sulfur plasma atmosphere. The effects of radiofrequency (RF) power and radiofrequency (RF) time on the properties of lithium sulfide prepared by the cold plasma method were investigated. The macroscopic morphology, microscopic morphology, elemental distribution and phase of the sulfide product (lithium sulfide) were further tested and analyzed. The results show that under the conditions of power ≥ 210 W and time ≥ 15 min, Li₂S₂-free lithium sulfide with high purity is generated; with the enhancement of power, lithium oxide is transformed into lithium sulfide. Subsequently, its electrochemical performance as a battery anode was tested. The test obtained: the specific capacity of charging is up to 216.9 mAh/g, and the specific capacity of discharging is up to 182.8 mAh/g; the impedance has a double capacitance to resist arcing, which can be carried out normally in the charging and discharging process, and it has a certain degree of electrochemical performance.