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The article presents the results of the study of the effect of additive hydrogarnet sludge on the process of carboalumination desiliconization of aluminate solution. It is proved that type-ahead hydrogarnet sludge significantly intensifies the process of ultra-deep desiliconization due to the catalytic effect of the surface of the slurry in accordance with the theory of heterogeneous catalysis. A mathematical process model for the process of superdeep desiliconization in increased turnover hydrogarnet sludge is presented.

The predominant types of high-grade iron deposits in China include skarn, sedimentary metamorphic (banded iron-formation, BIF-type), continental/submarine volcanic-hosted and magmatic Fe-Ti-V oxide deposits. Based on a comprehensive review of current studies on these deposits, this paper suggests that the oxygen concentration in atmosphere played an important role for the formation of BIFs, whereas the tectonic setting and deep magmatic differentiation processes are more important for the other types. Notably, both high temperature and high pressure experiments and melt inclusion studies indicate that during the differentiation, high temperature magmas could develop iron-rich magma via liquid immiscibility but not pure oxide melt (“iron ore magma”). Fe-P melt could be generated directly by liquid immiscibility under hydrous and oxidized condition. The formation of high-grade iron deposits is mostly associated with the processes related to multiple stages of superimposition, e.g., desiliconization and iron enrichment, removal of impurity, and remobilization and re-precipitation of iron. According to the temporal evolution, the high-grade iron deposit could be divided into multi-episode superimposition type (temporally discontinuous mineralization) and multi-stage superimposition type (temporally continuous mineralization). The former is represented by the sedimentary metamorphic iron deposit, and the latter includes those related to magmatic-hydrothermal fluids (e.g., skarn, volcanic-hosted and magmatic types).

The raw material for smelting brown corundum is high-quality bauxite. As the quality of bauxite decreases, the main impurity, silicon content, increases, which affects the product quality and smelting energy consumption. Additionally, the smelting process produces a significant amount of brown corundum fly dust (BCFD) with a low utilization rate, resulting in resource wastage. In order to utilize low-quality bauxite and BCFD, this article proposes the method of “roasting-alkali leaching.” Through mixed desilication, the impact of alkali leaching factors on desilication is investigated, analyzed the desiliconization mechanism of BCFD, and established the kinetics of the desilication reaction. Results indicated that the optimal conditions for mixed desilication are BCFD/bauxite mass ratio of 1:6, desilication temperature of 95°C, desilication time of 30 min, alkali concentration of 110 g/L, and liquid-solid ratio of 10:1, achieving a desilication rate of 60.90%. The Al-Si ratio (A/S) of the concentrate increases from 5.33 to 11.72, meeting the requirements for brown corundum smelting raw materials. The desilication reaction follows a solid shrinkage core model, with a kinetic equation of 1−2/3α−(1−α) 2/3  = 15.50exp[−29299/(RT)]·t, and an apparent activation energy of 29.30 kJ/mol. The synergistic mechanism involves fine particles of the BCFD adsorbing on the surface after mixing with the bauxite, increasing the mineral surface area and the activity of silicon, thereby accelerating the reaction rate.

In order to enhance control of hematite reverse flotation systems, we investigated desiliconization mechanism of surface nanobubbles (NBs) in reverse flotation of micro-fine hematite (MFH). The reverse flotation mechanism of NBs enhancing MFH was studied based on flotation dynamics tests, adsorption dynamics, adsorption dynamics calculations, and zeta potential tests. The results showed that the reverse flotation desilication of MFH can be completed 180 s earlier compared to the process without NBs, and that NBs can efficiently recover ultra-fine hematite with a particle size less than 10  μ m, which is about 5% higher than that without NBs. In addition, the presence of NBs improved the adsorption rate and adsorption capacity of the collector on quartz surfaces compared to the absence of NBs; especially; the adsorption rate was significantly higher than the absence of NBs when the adsorption time was less than 1.7 min and the maximum adsorption capacity was higher than the absence of NBs by 0.10 mg/g. The zeta potential test showed that NBs reduce the potential of the quartz surface, mainly because they promote the adsorption of Ca 2+ on the quartz surface to provide more active sites for the second adsorption of the collector, thus improving the desilicification rate of reverse flotation for MFH.

To optimize the operating conditions of the industrial fluidized bed reactor with a daily output of 3 tons of crude ZrCl 4 , crude ZrCl 4 was prepared by carbochlorination using desiliconization zirconia, C powder, and Cl 2 as raw materials. The thermodynamics and kinetics of carbochlorination reaction were investigated. Furthermore, quality data for the crude ZrCl 4 were modeled using a neural network gate recurrent unit (GRU) model. The experimental findings demonstrated that at elevated temperatures, the dominant formation equation is CO, with the reaction rate primarily governed by the surface reaction. Optimal results in chlorination rate, product quality, and slag discharge were achieved with a ZrO 2 : C of 100: 18–19 wt.%, a push speed of 70 kg/h, a material layer height of 1 m, and a chlorine flow rate of 75 kg/h. The loss value of GRU model training prediction is 0.021, and the curve convergence effect is good.

With the aid of dry pressing method, porous mullite ceramic supports were prepared successfully using desiliconized high alumina fly ash as main raw material, kaolin and alumina as auxiliary raw materials, and spherical graphite as pore-forming agent. The microstructure, bulk density, apparent porosity, water absorption, flexural strength and permeability of the ceramic supports were affected by the graphite dosage, sintering temperature and time. The mullite ceramic support with the addition 30 wt% graphite and sintered at 1400 °C for 2 h achieved the optimum comprehensive performances, whose apparent porosity, flexural strength and permeation flux achieved 55.7%, 8.5 MPa and 3.65 mL cm−2 min−1, respectively. After spin coated with the mixing sols of silica and alumina, and calcined at 1300 °C for 1 h, a layer of integrated and smooth mullite ceramic membrane was loaded on the support, and it attained the permeation flux of 3.41 mL cm−2 min−1. The obtained porous mullite ceramic support and membrane could be used as the filter materials for waste water treatment. This work is not only conducive to eliminate the environmental pollution caused by coal fly ash, but also save the resources, such as clay and alumina.

Low-grade copper oxide ore containing high silicon, composed of mainly of chrysocolla, quartz, muscovite, dolomite, kaolinite, and Na-feldspar, is a promising source for recovery, which processing by existing methods are not economical. An alkali-dissolving desilication method, followed by ammonia leaching for extraction of copper from low-grade copper oxide ore was explored in this research. The samples were characterized by using chemical analysis, X-ray diffraction, and SEM-EDS. While the Eh-pH diagrams were applied to be predicted the desilication mechanism for chrysocolla, quartz, muscovite, kaolinite, and Na-feldspar. The porous structure of desiliconized ore enhanced ammonia leaching of copper from copper oxide ore. The results show that the Si removal rate was 73.34 pct from copper oxide ore at the optimal desilication conditions: NaOH/copper oxide ore mass ratio 6/10, desiliconizing temperature 200 °C and desiliconization time 2 hour and that the Cu extraction from copper oxide ore desiliconized was 96.60 pct at the optimal ammonia leaching conditions of ammonia concentration 1.20 mol/L, ammonia-ammonium carbonate 0.9 mol/L, liquid-solid ratio 3:1 mL/g, and leaching time 1.5 hour. Consequently, the technology of processing of low-grade raw materials is proposed, that allows to increase the comprehensiveness of raw materials usage.

This article presents the results of studies on the autoclave desilicization of silicon-titanium concentrates of the Pizhemskoye field. Leaching was carried out using burnt lime as a reagent in the presence of the initiator NaOH. The work was carried out on two types of concentrate-pseudorutyl (siliceous-ilmenite) and leucoxene concentrate, which differ in the content of SiO 2 (14,03 and 36,8%, respectively) and Fe 2 O 3 (21,6 and 1,1%, respectively). The process was based on the selective binding of silica to calcium hydrometasilicate, which, upon subsequent calcination at 1050 °C, crystallizes into β-wollastonite.

The importance of emulsion zone formation in the basic oxygen steelmaking (BOF) process lies in its crucial role in enhancing refining efficiency. This study provides a comprehensive theoretical analysis of refining in BOF steelmaking, empowering steelmakers to optimize emulsion zone formation. By examining the contributions of decarburization, desiliconization, and dephosphorization from the emulsion zone, the study systematically investigates refining phenomena in distinct sections of the BOF converter, interconnected through recirculation streams. By utilizing FactSageTM and its macro-facilities, transient variations in metal and slag compositions, alongside varying terminal phosphorus levels for diverse emulsion zone dimensions, are quantified. Model findings highlight that emulsion and hotspot zones play roles in decarburization and desiliconization, while dephosphorization exclusively occurs within the emulsion zone. The model’s projections for carbon, silicon, and phosphorus removals (wt pct) and metal bath temperature concur with data obtained from plant trials. This comprehensive analysis enhances our understanding of the BOF steelmaking process, enabling steelmakers to fabricate the required emulsion zone strategically for optimal refining efficiency.

Examining the kinetics involved in the Argon Oxygen Decarburization (AOD) process, especially in the hotspot and emulsion zones within distinct reactors, can offer a deeper understanding of the refining mechanism in stainless-steelmaking. A predictive dynamic model has been formulated to estimate the effects of different refining processes, encompassing decarburization, desiliconization, demanganization, and chromium removal. The model includes a sub-model for heat loss calculation. The FactSage™ software, along with its macro programming capability, was utilized to incorporate thermochemical and kinetic information into the model. The model forecasts that the predominant chromium removal occurs within the hotspot zone, while carbon, silicon, and manganese removals occur in both the hotspot and emulsion zones. The predictions regarding the transient compositions of steel and slag, as well as the temperature of the steel bath, align with the plant data (Average of five heats), showcasing consistency.