Metallurgical Performance Research Articles

Adaptability analysis of H2-rich gas injection and sintered ore performance with different raw material ratios

As a source substitution technology that reduces pollutants emission and optimizes sinter properties, H2-rich gas injection-assisted iron ore sintering holds significant practical value. This study analyzed the adaptability of this technology to different ore blend ratios and basicity levels by comparing sintering indexes, pore structure, mineral phase composition, and metallurgical performance before and after H2-rich gas injection. The carbon emission reduction following H2-rich gas injection was calculated. The results indicate that increasing the proportion of high-silica, low-alumina ore (Ore-A) and basicity, along with H2-rich gas injection, can effectively enhance sinter yield and quality, but shrink the pore structure of sinter. Under H2-rich gas injection conditions, decreasing Ore-A ratios and increasing basicity can augment SFCA phase formation and mineral phase uniformity, thereby improving the anti-pulverization ability and reductivity of the sinter. H2-rich gas injection presents better adaptability to sintered ore with lower Ore-A ratio and basicity, which can achieve greater improvements in the sintering indexes, RDI, and RI. For a 265 m2 sinter plant producing sinter with 18 wt% Ore-A and 2.0 basicity, annual CO2 emissions can be reduced by approximately 40,000 t.

Influence of the Use of Ammonium Sulfate and Citric Acid on the Buoyancy of Minerals in Copper-cobalt Plant Process (Case of 635 Deposit Fed at Kambove

The objective pursued in this work is testing the performance of two new reagents namely ammonium sulfate and citric acid, on buoyancy of Kamfundwa ore currently treated at Kambove Concentrator. Optimization tests were conducted in order to determine the optimal doses of reagents commonly used, in this case Sodium hydrosulfide (NaSH), the amylxanthate potassium (KAX), Sodium silicate (Na2SiO3), and the mixture fuel-fatty acid. Metallurgical results obtained with these tests were used as reference for further work. Tests with citric acid alone could not improve the metallurgical results obtained under standard conditions, the same finding was observed in tests with ammonium sulfate alone and that performance seemed to be much closer to those of reference tests. We finally realized flotation tests by combining citric acid and ammonium sulfate in order to streamline the synergy of these two reagents. It appears from these tests that at the dose of 600 g / t of citric acid and 400 g / t of ammonium sulfate, metallurgical performance obtained are better than previously. The following results were achieved during the batch flotation tests: 18.87% as copper content of the head concentrate, with a recovery rate of 55.34%, and 10.81% as copper content of the global concentrate; for a copper recovery corresponding to 80.94%. This mixture of citric acid and ammonium sulfate has allowed good selectivity and a reduction of gangue trained to the concentrate.

Influence of the Mixture of Xanthates collectors on the Flottation of Difficult Copper Ici de Oré to Float-Case of Minerals Fill 18 Deposit Shangulowe

This paper presents the results of a study conducted to highlight the influence of the mixture of xanthate collectors on the flotation of copper oxide ores. The Shangolowe deposit sample assayed 3.22% copper and 0.08% cobalt, and by means of mineralogy and chemical analysis the gangue appears dolomitic. Test optimization ratio and the main sulfudizing collector were performed, testing after which the dosage rates of 4000g NaSH / dT ore and 400g KAX /dT ore were used as a reference for further testing. Xanthate collectors namely: KAX, KEX, SIBX and SNPX were tested alone and their specific behaviors were reported. The study showed that KAX increase the recovery and three other collectors improved concentrates quality. They were then taken two to two mixed in the proportions of 25% -75% 50% -50% 75% -25%. It appears from these tests that the mix-KAX/SIBX taken in ratios of 75 and 25%, stood out all tests because it offered good selectivity and improved metallurgical performance. Comparative testing of cleaning under standard conditions and the best test mixture, also confirmed an improvement in the selectivity of 7 points compared to the usual KAX. A comparison of the collector’s costs, helped highlight a desired gain per ton contained copper with the use of mixed collectors which was about 13% compared to the use of KAX alone. Operating conditions and flotation scheme on the test which offered the best metallurgical performance subsequently proposed to the operator, who was consolidating the results obtained previously with cyclic tests in laboratory and pilot plant.

Prospective on applying machine learning in computational fluid dynamics (CFD) simulation of metallurgical reactors

Metallurgical reactors, especially in ironmaking/steelmaking process, characterise with high-temperature turbulence, multiphase flow, mass/heat transfer and reactions. Computational fluid dynamics (CFD) simulation-based design and optimisation are of significance for efficient metallurgical performance. However, the difficulty and cost to numerically solve the nonlinear controlling equations combined with data pre/post-processing make the whole CFD simulation process time-consuming, which makes it challenging to provide in-time feedback for industrial practices. The popularisation and prosperous development of machine learning bring new opportunities for promoting CFD performance. Discussion has been made on the current research progress of applying machine learning in the whole CFD workflow including pre-processing, solving, and post-processing. Among them, the time consumed by manual pre-processing exceeds 50% of CFD tasks in general. The machine learning or parametric modelling methods can reduce pre-processing time by three orders in the estimate. The solving step is expected to be accelerated by 5 to 1000 times using machine learning. A brief review of machine learning coupled CFD is provided, as is a prospective on its development. Discussion is presented on the main functions, challenges, typical techniques and future directions of applying machine learning in CFD simulation of metallurgical reactors, for the purpose of making CFD faster, more accurate, and better visualised based on the metallurgical practices.

Effect of Al2O3 on the sintering process and the metallurgical performance of sinter

ABSTRACT The trend to process iron ore with increasing Al2O3 content has affected the performance of sinter and blast furnace operations. Formation of the primary melts and phase properties such as morphology and reducibility of the iron ore could be easily influenced by the Al2O3 content. In this paper, the effect of the Al2O3 content in the sinter samples, which range from 1.49 to 3.24 wt-% with a basicity of 2.0, MgO/Al2O3 ratio of 1.05, on the sintering process and the metallurgical performance were studied through a sinter pot experiment and a reduction experiment. The results show that an increase in the Al2O3 content deteriorated the sintering index, and the yield and tumble index decreased by 7.61% and 12.02%, respectively. The sintering index was relatively stable when the Al2O3 content was between 2.10 and 2.95 wt-%. Low-reduction columnar silico-ferrite of calcium and aluminum increased with the increasing Al2O3 content, hindered the reduction index of the sinter. The low-temperature reduction degradation index change was only around 2%, due to the higher MgO content of the sinter promoting magnetite formation.

Role of the Biogenic Carbon Physicochemical Properties in the Manufacturing and Industrial Transferability of Mill Scale-Based Self-Reducing Briquettes

The recovery of iron contained in mill scale rather than iron ore can be considered a promising valorization pathway for this waste, especially if carried out through reduction using biogenic carbon sources. Nevertheless, the physicochemical properties of the latter may hinder the industrial transferability of such a pathway. In this work, the mechanical and metallurgical behavior of self-reduced briquettes composed of mill scale and four biogenic carbons (with increasing ratios of fixed carbon to volatile matter and ash) was studied. Each sample achieved mechanical performance above the benchmarks established for their application in metallurgical furnaces, although the presence of alkali compounds in the ash negatively affected the water resistance of the briquettes. In terms of metallurgical performance, although agglomeration successfully exploited the reduction by volatiles from 750 °C, full iron recovery and slag separation required an amount of fixed carbon higher than 6.93% and a heat treatment temperature of 1400 °C. Finally, the presence of Ca-, Al-, and Si- compounds in the ash was essential for the creation of a slag compatible with steelmaking processes and capable of retaining both phosphorus and sulfur, hence protecting the recovered iron.

Synergistic reutilization of spent pot lining and water quenched blast furnace slag as mold flux

A treatment method that synergistic reusing spent pot lining (SPL) and blast furnace slag (BFS) as mold flux (a functional material used in steel enterprises) was developed to achieve the harmless treatment of hazardous substances and recycling of valuable resources in spent pot lining. Mold flux made of SPL and BFS shows outstanding metallurgical performance. More importantly, toxic fluoride and cyanide in SPL were effectively harmless-treated utilizing industrial waste heat after making mold flux. The fluorine leaching ratio of amorphous mold flux residual after a leach test for 128 h is 1.08 wt%, which is 1/24 of that of raw SPL. The microstructure characterization proved the addition of BFS enhanced the fluorine immobilization effect by optimizing the network structure of amorphous mold flux residue. Compared to the traditional landfill treatment, the estimated additional economic benefits of processing one ton of SPL with this method are approximately 1924 USD.

Metallurgical performance evaluation of space-weathered Chang’e-5 lunar soil

Metallurgical performance evaluation of space-weathered Chang’e-5 lunar soil

Effective utilization of Ni-Cr bearing composite burdens for high-Cr ferronickel preparation

In this paper, two types of Ni-Cr bearing composite burdens including SP1 (79% Ni-bearing sinter and 21% Cr-bearing oxide pellets) and SP2 (84% Ni-bearing sinter and 16% Cr-bearing pre-reduced pellets) were used for the more efficient preparation of high-Cr ferronickel. Based on the metallurgical performance characterization, thermodynamic analysis and smelting parameters optimization, the qualified high-Cr ferronickel were prepared by the utilization of the Ni-Cr bearing composite burdens. The recovery rates of iron, chromium and nickel exceed 95%, 90% and 98% whereas their grades are 85.56–85.88%, 7.82–8.02% and 1.59–1.62%, respectively. Compared with SP1, SP2 possesses lower smelting duration, which indicates the appropriate proportioning of Cr-bearing pre-reduced pellets is beneficial for the smelting process. The obtained high-Cr ferronickel consisting of (Fe, Cr)3C and (Fe, Cr)7C3 can be used as a low-cost substitute for the conventional raw materials of 200 or 300 series of stainless steel.

Effect of Particle Size and Starch Gelatinization on the Mechanical and Metallurgical Performance of Jarosite Plus Blast Furnace Sludge Self-Reducing Briquettes

Jarosite and blast furnace sludge (BFS) are two of the main wastes from hydrometallurgical zinc production and iron production by blast furnace, respectively. Jarosite is a hazardous material that can, however, be reused in the steel industry after the recovering of the iron contained within it through carbothermal reduction in which BFS is exploited as a reducing agent. Yet, both wastes have a powdery nature that makes it necessary to agglomerate them for industrial use. On the other hand, despite the advantages of producing a self-reducing product, the particle size of the starting powders and the level of gelatinization of the binder could play a crucial role on the mechanical and metallurgical performance and, consequently, on the industrial applicability of the briquettes. Accordingly, two powder particle sizes (very fine sand vs. coarse silt) and three degree of corn starch binder retrogradation (10%, 30% and non-gelatinized starch) were used to produce briquettes, and their influence was studied by experimental and statistical investigation. The results showed that gelatinization plays the main role on the mechanical properties of briquettes, while particle size affects both density and reduction behavior; in particular, although all the mixtures were able to recover iron at 950 °C the most optimal mixture were obtained by using a granulometry of 63–125 µm for jarosite and less than 63 µm for BFS, while the local maximum of mechanical performance was obtained for a 30% starch retrogradation level.Graphical

Machine-Learning Analysis of the Canadian Royalties Grinding Circuit

This work aimed to understand the relationships between grinding variables and the P80 (80% passing size) of a grinding circuit (feed to flotation). Canadian Royalties want to obtain and reduce variations in the P80, which is currently 65 micrometres. Thus, principal component analysis (PCA), part of machine learning, was utilized to better understand the factors that significantly influence the P80. PCA is meant to be used as a guideline for plant metallurgists to determine how the grinding circuit factors influence P80; thus, the variables can be manipulated to lower P80 fluctuations. PCA revealed that the head grade of the ore (pentlandite (Pn), chalcopyrite (Cp), pyrrhotite (Po) and non-sulphide gangue (NSG)) and the primary ball mill power were weakly correlated with P80. However, the ore level in the silo, flowrate to cyclones, cyclone pressure, percent solids and the feed tonnage rate to the primary ball mill were strongly correlated with P80. This information can be used to develop a strategy to control the P80 of the grinding circuit and provide a more consistent grind size to the flotation circuit, which can positively impact metallurgical performance.

Flowsheet development for and commissioning of the Kamoa-Kakula project

The Kamoa-Kakula copper resource, located west of Kolwezi in the Democratic Republic of the Congo, was discovered and explored by Ivanhoe from 2008/9 on. As a greenfield project with prospects of high grade ore and a long life-of-mine, the need for best practice flowsheet development was recognised, so as to ensure sustainability of metallurgical performance at the at the maximum economic level from the orebody during metallurgical operations. Process Mineralogy, a hybrid discipline, has been developed in the mining industry over the last forty years, and its proper use has seen very successful outcomes in flowsheet development (Bradshaw, 2014; Lotter, 2011; Lotter et al., 2003; McKay et al., 2007; Pease et al., 2005). Drill core was sampled at site across six phases of flowsheet development that worked with the developing mine plan. The two main geomet units were hypogene and supergene, with the hypogene being unusually rich in bornite. The main variability is between supergene and hypogene, and between Kamoa and Kakula, but with less spatial variability within them. The first viable flowsheet was developed and demonstrated in nine months of test work, followed by various revisions and iterations as required by the discovery of variable mineralogy. The first flowsheet, called “Milestone”, was then challenged with an opportunity for a simpler but better-performing flowsheet, which became known as IFS4A. The simultaneous discovery of the Kakula resource refocussed the project due to its shallower depth and higher grade. Laboratory scale flotation testing using IFS4A in Phase 6 of Kamoa and two drill-holes of Kakula quickly confirmed that the Kakula ore outperformed the Kamoa supergene ore using this flowsheet. A mini-pilot plant campaign was run in 2019 with this flowsheet plus modifications, using 985 kg of metallurgical drill cores material to demonstrate the full flowsheet mass and value balance on a continuous operating campaign. This mass and value balance produced an estimated 85.6 % Cu recovery with a saleable concentrate grading 57.3 % Cu. Whereas this paper concentrates on the mineralogy and its contribution to process implications such as grinding requirements and flotation strategy, it is recognized that first-class design, engineering and construction contributed in no small measure to the successful start-up. This mass and value balance was used in the design of the grinding and flotation circuits, and contributed to the successful commissioning of the new concentrator in 2021, which averaged a recovery of 84.7 % at a grade of 50.5 % Cu, in good agreement with the testwork. A McNulty model for the commissioning data shows a better than Type 1A start-up. The flowsheet development part of the project is discussed in this paper as a case study.

Effect of air profiling and frother concentration on a flotation bank performance

The impact of air distribution on the metallurgical performance of a flotation bank operating with a mineral slurry having a moderate and high frother concentration is assessed. A flotation bank of two and three 5L Denver cells was implemented, and air flow was distributed down the bank as increasing and decreasing profiles. It was observed that when operating the bank configurations with a moderate frother concentration (10 ppm DF 400) the increasing profile provided the highest Cu enrichment ratio at the expense of a slight reduction in Cu recovery. This increase in selectivity was mainly due to a significant reduction in the water recovery and mass-pull in the first cell. When the bank operated with a high frother concentration, i.e., well beyond the CCC, a significant increase in water recovery was observed, producing a significant loss in selectivity that could not be compensated by air profiling.

Optimizing liberation of phosphate ore through high voltage pulse fragmentation

This study investigates the selective high voltage pulse (HVP) fragmentation and its role in enhancing the metallurgical performance in phosphate ore processing. We have adapted the use of HVP fragmentation to enable the complete comminution of the considered ore, without the need for additional grinding steps. The efficiency of the HVP process strongly depends upon two parameters – the discharge ratio and the electric field, which, combined, allow for an improved liberation. Furthermore, for the same feed, the high voltage pulse fragmentation provides a coarser product with fewer fines. This study also emphasizes an improved liberation of the target mineral, carbonate fluorapatite, in the 100–315 μm fraction, while concentrating gangue minerals in the <100 μm size fraction. These findings are supported by X-ray tomography, validating the principle of pre-weakening induced by high voltage pulses on phosphate ore and further confirming the significance of our research.

Innovative B-PA binder for enhanced cold pelletization: a sustainable strategy for utilizing iron-containing dust and sludge

A large amount of iron dust and sludge is produced in the process of iron and steel metallurgy, and its efficient utilization has important economic value and environmental significance. In this study, a method of cold-bonded aggregate is used to co-process stainless steel pickling sludge (SSPS) and gravity dust (GD). The preparation process parameters of cold-bonded pellet are optimized. The role mechanism of the binder on cold-bonded aggregates is studied, and a new type of composite binder, bentonite-plant asphalt (B-PA), is invented. The optimal ratio of bentonite to plant asphalt is determined to be 3:1. The metallurgical performance of B-PA agglomerates is tested, with results showing an RDI+3.15 at 93.6%, a RI at 79.3%, an RSI at 14.2%, a DI at 4.01%, and a thermal cracking temperature reaching 721 °C. The microstructure of the agglomerates after performance testing is characterized using XRD and SEM. This cold-bonding pelletization technology is expected to be widely used in the efficient comprehensive utilization of metallurgical dust in the future, which is of great significance for reducing costs, increasing efficiency, and promoting green environmental protection in the steel industry.

The impact of batch flotation tests on the industrial plant prediction

To predict the metallurgical results of industrial plants, laboratory batch flotation tests are carried out, relating both operations through scale-up factors. However, robust scale-up procedures and well-defined laboratory protocols are necessary to reach reliable results at industrial scale. In this paper, results from different flotation batch tests are presented, analysing the effect of batch protocol in terms of operating conditions, operator, ore type, water quality, and others on the metallurgical response. Additionally, the ability of batch responses to describe industrial operations and determine scale-up factors was analysed. Then, a sensitivity analysis was carried out, considering the effect of batch and industrial conditions on the estimation of scale-up factors. Results showed that the batch response significantly changes, depending on the operating conditions, flotation operator, and batch flotation machine, even for the same cell design. Additionally, it was observed that the batch recovery significantly changes when modifying ore type and water quality, which can cause changes in batch and/or industrial operation, affecting the scale-up factors. In addition, results showed that the scale-up factors varied significantly by changing operating conditions in a batch cell. This also occurs in plants when metallurgical performance changes, for example, due to a modification in launder design and/or operating condition, to increase recovery, or due to control limitations that prevent efficient metallurgical performance.

Challenges in flotation scale-up: The impact of flotation kinetics and froth transport

At present, data from industrial flotation operations is still limited and more tests and in-depth studies are required to improve the experimental procedures, measurement devices and analysis, to validate and interpret scale-up factors from batch to plant flotation operations.The new methodologies have contributed to improve predictions of flotation metallurgical performance using more refined scale-up methods, for example, analyzing the scale-up factor by size and liberation classes. These will allow for selecting the best equipment for each mineral and flotation stage (rougher, cleaner and scavenger).In this work, the effect of the pulp zone hydrodynamics affecting the collection residence time and flotation kinetics, and the froth transport, on the overall scale-up factors (typically around 1.8–2.3) was evaluated per particle size classes in the range of 22.5 to 300 µm. Two effects were found that partially explain the scale-up factor in the pulp zone, such as the pulp mixing regime (4–16%) depending on the cells number, and the solids segregation (2–7%) that decreases the residence time of larger particles. However, the most important contribution was the froth transport characteristics that determines the froth recovery which accounted for 48–58% of the scale-up factor, also increasing with particle size. In addition, it was found that the remaining percentage of the overall scale-up factor, around 31%, includes the uncertainty in the collection residence time estimation, which is lower than the effective pulp residence time, and the larger residence time of bubbles in industrial cells. Both effects hinder the identification of the actual flotation rate in the pulp zone.

Fine and ultrafine flotation with the Concorde CellTM – A journey

The Concorde Cell is a high-intensity pneumatic flotation cell dedicated to fines and ultrafines. Its development by Professor Graeme Jameson and later on by Metso was driven by two considerations: a reduction in bubble size and an increase in the shear rate and energy dissipation rate increases the particle–bubble collision and attachment efficiencies of fine particles. The Concorde Cell is a technology which produces fine air bubbles with high carrying capacity, thereby allowing increased capacity per unit; smaller footprint and a greater recovery of valuable fine particles which can be lost in other flotation cells. In addition, with a smaller number of flotation stages or less recycle required to achieve the desired recoveries, operational expenditures like power, water and reagents can be reduced.In this article, the potential of the Concorde Cell is explored through six cases, from base metals to metallurgical coal. Its main operating parameters, Air-to-Pulp Ratio, froth washing, froth depth and tailings recycle ratio, are investigated and show that the metallurgical performance of the Concorde Cell follows expectations based on the literature. Amongst others, higher APR leads to higher mass pulls and higher recoveries but lower grades, deeper froth depth increases selectivity… But the data also demonstrate the typical complexity of flotation, whereby the negative impact of increased APR can be compensated with froth washing to maintain high grades at high recoveries for example.About ten industrial scale flotation projects worldwide are deploying the Concorde CellTM. The examples of a metallurgical coal washing plant in Australia and of a copper plant in Zambia prove the capacity of the Concorde Cell to better recover the fines and ultrafines while providing high selectivity. In the two case studies, the Concorde Cell outperformed the previous technology specifically on the finest fractions of the processed streams.

Tribological, mechanical, and metallurgical performance of natural fiber-reinforced composites: A comprehensive review

Composite materials have an ever-increasing demand for their application in numerous applications such as aerospace, automobile, petroleum, etc. These materials vary according to their chemical composition, properties, manufacturing techniques, etc. Natural fiber-reinforced composites are the composites where natural fibers such as plant, animal, and mineral fibers are used as reinforcement material. Reinforcement of these fibers yields composite material with extensive properties such as high strength, durability, reliability, etc. These properties lead them to commercial applications in several areas. Therefore, this paper describes various characteristics of the matrix, reinforcement, and resin used for natural fiber composite materials. Also, multiple parameters that affect the growth of these composites are investigated. The tribological behavior of natural fiber composites is focused mainly on friction, wear, and lubrication. Furthermore, the material's mechanical performance and metallurgical behavior are also given significant importance. These materials’ application in various fields is explored separately, and multiple conclusions are drawn.

Multi-layer additive manufacturing on nickel-based superalloy by optimization of pulsed mode process parameters of single-layer bead geometry

Recent advancements in the wire arc additive manufacturing (WAAM) process for nickel-based superalloys have had a substantial impact on metal additive manufacturing industries such as aerospace, energy, and construction. The input process parameters influence the WAAM part's dimensional accuracy, process stability, and other critical impacts. The quality of each weld layers in WAAM can be controlled by various process parameters. In this study, a single-layer bead was deposited from Hastelloy C-22 using the pulsed mode gas tungsten arc welding (PC-GTAW) process. The chosen input process parameters include pulse frequency (X1), peak current (X2), and pulse on time (X3). The design of experiments (DoE) statistical quality tool was used to optimize the parameters, and the response surface m`ethodology (RSM) technique was used to develop the design matrix. The experiments were conducted based on central composite design (CCD), and their resulting responses bead width (Y1), height (Y2), and depth of penetration (Y3) were evaluated using optical microscopy. The results of the geometrical analysis have revealed a significant correlation between the characteristics of the layer and the parameters of the process. The analysis of variance (ANOVA) method was employed to verify the validity of the actual and predicted models. The model was experimentally validated using the established optimal process parameters, and the mechanical and metallurgical performance was evaluated. The microstructure of the single-layer exhibits equiaxed, cellular, and columnar structures at various regions. The pulse mode process was found to effectively reduce elemental segregation, improve the microstructure, and enhance the mechanical properties of the weld layer. The multi-layer experiments were carried out using the optimal process parameters of a single layer. According to metallographic investigations, the multi-layer that has been deposited exhibits a lack of cracks and porosity. This study provides new insights into the stabilized properties necessary to achieve optimal process parameters and metallurgical characteristics in the robust wire arc additive manufacturing of Hastelloy C-22.