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By M. H. Morcali

Pistachio nut shells, an agricultural waste biomass, and Lewatit TP 214, a commercial sorbent, were investigated as adsorbents for the adsorption of platinum from dilute hexachloroplatinic acid solutions. Before the pistachio nut shells were carbonized, adsorption percentage was 65%, whereas Lewatit TP 214 ensured almost 100% adsorption. However, after the pistachio nut shell was carbonized at 1,000° C under an argon atmosphere, the platinum adsorption (%) increased two-fold. The effects of such parameters as sorbent dosage, contact time, temperature and solution pH on adsorption were studied in detail in batch mode. The adsorption equilibrium data were best fitted with the Langmuir isotherm model. The maximum adsorption capacities, Qmax, at 25° C were found to be 38.31 and 33.22 mg/g for the carbonized pistachio nut shell and Lewatit TP 214, respectively. The adsorption of platinum on both sorbents was found to be described by the pseudo-second-order kinetic model. The results indicated that the activated carbon prepared from pistachio nut shells can be effectively used for the removal of platinum from acidic solutions.

By S. G. Zahony

The Moris gold deposit resides in a massive ridge-forming sulfide-poor epithermal quartz and calcite vein system and consists of a mineable reserve of four million tons of 2.1gm Au/ton. Post-mineral normal faulting along the hanging wall of the main fissure has caused a hogback-like exposure of the vein, allowing for inexpensive opencut mining. The vein formed between pre-Cretaceous(?) phyllitic clastic sedimentary units in the footwall and Tertiary andesitic volcanic rocks in the hanging wall. Part of the ore reserve is hosted in a Tertiary conglomerate that rests unconformably atop the phyllitic footwall sequence. The original unoxidized vein material contained substantially less than 1 gram Au/ton. A four-fold upgrading of gold occurred by enrichment when gold recrystallization took place in the electric fields of oxidizing pyrite cubes.

Jan 1, 1993

he leaching behavior of palladium in ammoniacal solutions has been investigated by using the rotating disk technique in an autoclave. The study included the effect of rotating speed, temperature, oxygen pressure, composition of ammoniacal solutions, and catalyst on the overall leaching rate. The dissolution of palladium in ammoniacal solutions was discussed in view of the thermodynamics and a kinetic model. Even though the potential-pH diagram suggests that palladium metal can dissolve in ammoniacal solutions at room temperature, it was found that the dissolution was too slow at temperatures below 100°C but was significantly improved at higher temperatures. It was also found that the rotating speed of palladium disk had no effect on the leaching rate. The apparent activation energy was found to be 69.7 kJ/mole. Based on the results obtained, it is concluded that the dissolution of palladium is controlled by chemical reaction.

Jan 1, 1997

By William C. Howe

This paper describes the technical status of the atmospheric pressure fluidized bed combustion (AFBC) process for utility steam generation. Major areas where AFBC development work is needed are discussed. Various approaches to solving these key issues are identified and the ongoing research and development programs addressing the key development areas are described. Other significant programs pertaining to the development of AFBC for utility steam generation are also discussed and needs for future work identified.

Jan 1, 1978

By J. Leonard Frame

A coal-fired fluidized bed combustion (FBC) system will be installed at the Owatonna Tool Company, Owatonna, Minnesota. Two FBC combustors will burn solid fuels: coal, petroleum coke, and wood and paper wastes. Crushed dolomitic limestone will be used to control sulfur emissions to EPA limits. The combustors will supply indirectly heated hot air and hot water for paint drying operations, washing processes, and space heating. The program is sponsored by the United States Department of Energy and the Owatonna Tool Company, and is one of five programs designed to demonstrate industrial applications of coal-fired fluidized bed equipment. The paper will describe the combustion system and the results of development tests with dolomitic limestone for sulfur emission control.

Jan 1, 1978

By C. Cardoso, G. Bermudez, A. Jalili

Bigger flotation cells can result in larger froth surface areas and longer froth transport distances, this has been credited to impact froth recovery. Thanks to recent advancements, the newer flotation machines can be designed with different launder and crowder arrangements to enhance froth management. Nevertheless, lower head grades, complex ores and even larger mechanical flotation cells can lead to insufficient froth collection, even if the cell is equipped with the most recent flotation advancements like the center launder design. Aforementioned issue can become critical at the end of the flotation row. Increased crowding has been proven to be a solution to overcome inadequate froth recovery. However, scaling-up crowders for larger flotation cells can rise challenges, particularly in terms of structural limits and design for service. This paper presents the development journey for the Spider Crowder Upgrade, an advancement to improve froth collection in large flotation cells that are already equipped with center launders.

Feb 1, 2024

By L. Xiao

Using K-oleate as a collector and alizarin red S (ARS) as a modifying agent, selective depression of dolomite from francolite was achieved in alkaline medium (pH> 9.0). Interestingly. ARS was also found to depress igneous apatite in alkaline medium in oleate flotation of apatite and calcite. Adsorption of ARS alone on dolomite was found to be higher than that on francolite. Complimentary adsorption experiments of ARS and K-oleate showed that oleate adsorption was increased in the presence of ARS on francolite but not on dolomite. K-oleate adsorbs on both francolite and dolomite and causes precipitation of calcium and magnesium oleate. Such precipitates can be pre-vented when ARS is present. The results are explained in terms of competitive adsorption for the active sites on francolite and dolomite by oleate and ARS, and their interactions with dis-solved mineral species in solution.

Jan 1, 1988

By R. Haecker, S. Gupta, P. Somasundaran

Rock disintegration processes are usually inefficient and costly operations in mineral beneficiation, mine development and oil well preparations. Thus, there is a strong need for improving the energy efficiency of unit operations such as drilling and comminution. The effects of selected cations and anions on drilling efficiency in a hard rock formation (Dakota Sandstone) were studied. The zeta potentials and the tensile strengths of the drilled samples were measured under similar chemical conditions. The chemicals tested included MgCl2, Na2CO3, AlCl3, NaCl and Dodecylammonium chloride. The results indicated that drilling rates can be enhanced or retarded depending on chemical conditions such as the solution pH and the type and concentration of reagents. Drilling data are correlated with mechanical (tensile strength) and interfacial (zeta potential) properties of the rock formation. The mechanisms involved are discussed in light of Rehbinder's and Westwood's theories.

Jan 1, 2000

By Mark Cadzow, Rodney Lamb

CARBAD is a recently developed Australian process for the recovery of gold and platinum group metals (PGM). The process relies on the selective agglomeration phenomena of the gold and PGM to capture the mineral in a carbon-hydrocarbon media. The precious minerals are then extracted from the loaded media by a solvent gold room process producing a relatively pure concentrate. The media is then reformed and recycled. The process development from batch test work to a 5 t/h commercial scale CARBAD plant is discussed. The operation and results of processing a variety of ore types at several alluvial and hardrock gold mines is examined. The operating and capital costs for the CARBAD process shows that it is significantly less than that the conventional CIP/CIL. The environmental safety of the process is a major feature where precious metal deposits are located within urban environments or within wilderness areas.

Jan 1, 1989

By R. D. Miller

Application of shallow seismic reflection to problems associated with mineral exploration, mine planning, abandoned-mine detection, and environmental evaluation has been successful in a variety of geologic settings. Increased dynamic range of recording equipment and decreased cost of processing hardware and software have made shallow seismic reflection a cost-effective means of imaging geologic targets significant to mining operations. Seismic data possess sufficient resolution in many areas to detect faulting with displacement of less than 3 m in coal seams as thin as 2 m at depths of 200 m. Subsurface voids associated with abandoned mines at depths of less than 20 m can be detected and mapped. Seismic reflection has been successful mapping disturbed subsurface associated with dissolution mining of salt Complex geologic features associated with deposition of various hydrothermal minerals have been effectively mapped with high resolution seismic reflection at depths from 80 to over 300 m. Faults in sulfur-bearing cap rock over salt domes have been accurately located, allowing improved efficiency of the dissolution mining process. Shallow high-resolution seismic reflection has the potential to significantly enhance the economics and safety of mine operations.

Jan 1, 1993

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

Researchers from the U.S. National Institute for Occupational Health and Safety (NIOSH) studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the continuous personal dust monitor) within a sociotechnical system (STS) framework to mitigate respirable dust sources. The results address how to best incorporate the overarching principles of meta-design STS during the technology integration process. Specifically, quantitative and qualitative data show that a prominent focus on the social factors within an STS framework could help reduce organizational unpredictability and may improve communication within the system to help reduce technology adoption time.

By Terry W. Engelhart

"A computer-based approach to online supervisory control and operations management of bulk materials handling terminals". This paper describes an integrated computer facility supporting the functions and responsibilities of shift operations, scheduling, maintenance and management using real-time interactive techniques. The functions and responsibilities as related to coal export terminals are specifically addressed, although these functions would be equally applicable to other terminal configurations and other commodities. A discussion of the resulting benefits are presented: - throughput efficiency - long-term planning and scheduling, using simulation - operations monitoring and protection - demurrage/despatch optimization - preventative maintenance - operational productivity

Jan 1, 1982

By Felipe Calizaya, Sekhar Bhattacharyya

Noise-induced hearing loss (NIHL) is prevalent in mechanized underground mines. Federal regulations are often not complied with effectively. Miners are also prone to ignoring administrative guidelines and/or personal protective equipment for hearing conservation. As a result, quality of life among experienced miners plummets while occupational risks increase at workplaces. This research focused on auxiliary fans used in underground mines. These fans work at high rotational speed and generate extremely high levels of noise in close proximity to miners. Silencers used are often of little effect due to poor maintenance. A new silencer is tried in the laboratory with the objective of easy maintenance and resulting reduction of noise exposure for miners.

By Tristan Joubert, Fabio Panella, LiLing Chen, Yung Loo, Michael Devriendt, Nasir Qureshi, Ahmad Ali

Tunnel inspections have traditionally been carried out manually by inspectors writing up observations and taking photos of defects. The results from the inspection and the defects observed are dependent upon the rigor of the inspectors and may be subject to repeatability and consistency issues and is often time consuming with elevated health and safety risks. This paper will discuss work that is being carried out in developing and implementing an innovative hardware and software solution integrating machine learning to automate the process of capturing objective tunnel condition information, offering cost and programme savings as well as health and safety improvements

Jun 13, 2023

By A. Porvali, V. Agarwal, M. Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2•H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can be treated further with NaOH solution to form REE hydroxides. This study focuses on metamodeling of a simulated flowsheet with design of experiments (DOE). Based on literature survey, a process flowsheet was developed using HSC Sim software. The created flowsheet focuses on circulation of solution containing Na+, K+, SO42- ions and impurities liberated in the NaOH treatment of double salt precipitate. The effect of seven parameters (P1-P7) on seven responses (R1-R7) were modeled using central composite design (CCD). INTRODUCTION Nickel metal hydride (NiMH) battery waste can be considered as an urban mineral due to the presence of valuable metals like: Ni, Co and rare earth elements (REE) (Larsson et al., 2013). In NiMH battery waste leaching experiments, sulfuric acid has often been employed as a lixiviant (Pietrelli et al., 2002,Zhang et al., 1999,Rodrigues and Mansur, 2010,Porvali et al., 2018). The key advantages of sulfuric acid are its stability and cost-effectiveness compared to other mineral acids such as HCl and HNO3. However, the usage of sulfuric acid in NiMH battery waste leaching poses simultaneous challenges and advantages. Limited REE solubility can be taken as benefit when recovering REEs double sulfates after solid-liquid separation. However, sodium and potassium hydroxide, present in electrolyte residues in the battery waste, can cause in-situ precipitation already during leaching due to limited solubility, thus decreasing the total REE recovery (Porvali et al., 2018). However, this problem can be circumvented by washing the electrolyte residues off the raw materials. Subsequently, the REEs may be precipitated in bulk as a mixed double salt out from the solution at very low pH with minimal co-precipitation of Ni and other metals. This relatively easy separation method can be extremely advantageous in the case of such a complex solution matrix with relatively high REE concentrations (conc.). Once REEs have been precipitated as double sulfates as per eq. (1) (Porvali et al., 2018), the resulting double salt precipitate lacks applications without further treatment. Direct thermal treatment would generate sulfur dioxide emissions and likely require high temperatures in order to transform double sulfates into REE oxides. Furthermore, the precipitate contains Na ions, which would need to be removed by chemical treatment from the calcined REE product. In the context of circularity of raw materials, it can be taken of a remarkable benefit if the sodium and sulfur present in the double salt could be reused instead of wasting them into the side streams. To that end, in this simulation study, the double salts are converted by dissolution and precipitation to hydroxides which are readily treatable, e.g. with total dissolution and solvent extraction, for further purification (Abreu and Morais, 2010):

Jan 1, 2019

By P. Rusin

Many oxide silver and molybdenum deposits remain undeveloped because chemical extraction yields poor recoveries or is environ-mentally unacceptable. Bio-reductive leaching of such ore samples at MBX resulted in high recoveries of silver and molybdenum. When baseline 3-day cyanide bottle roll tests were conducted on manganiferous oxide silver ore, 13.7% of the silver was extracted. In contrast, 86% of the silver was microbially solubilized into the organic growth medium by bio-reduction with 99.8% dissolution of manganese. A follow-up cyanide bottle roll test yielded an additional 8.5% silver recovery for a total recovery of 94.5%. Baseline 3-day acid bottle roll tests of the iron oxide molybdenum ore yielded 1.8% moly. However, bio-reduction solubilized 93.3% of the moly into the growth medium. An additional 0.3% moly was recovered during the follow-up acid bottle roll test. Microbial treatment of refractory oxide ores with bio-reductive bacteria resulted in higher recoveries of silver and molybdenum than conventional chemical leaching. The bioleaching process occurred at a near-neutral pH at ambient temperatures. The bacterial solubilization of silver and moly was achieved without the use of cyanide or sulfuric acid.

Jan 1, 1992

By T. Qiu

"The purpose of this study is to investigate the effect of the dosage of sodium hypochlorite as activator on the flotations of depressed marmatite and depressed chalcopyrite, with a focus on activation-flotation kinetics. Four flotation kinetic models were applied to test data using 1stOpt statistical analysis software to estimate the relationships between the maximum flotation recovery rates for the depressed marmatite and depressed chalcopyrite, the flotation rate constants and the sodium hypochlorite dosages. Within the range investigated, the highest flotation performances of depressed marmatite and depressed chalcopyrite were obtained at 2.5 mL/L sodium hypochlorite with zinc recovery rate of 93.8 percent and 3 mL/L sodium hypochlorite with copper recovery rate of 94.6 percent, respectively, after four minutes of flotation. A second-order model with rectangular distribution of flotabilities gave the best fit to test data collected at various sodium hypochlorite dosages. For the highest flotation performances of depressed marmatite and depressed chalcopyrite, the respective equations of their flotation models were derived and presented.IntroductionCyanidation tailings are the solid residues generated by gold plants that use cyanide to extract gold (Lv, Ding and Qian, 2015; Zhang, Li and Yu, 2013). Because of increasing demand for gold, the Chinese gold industry has developed rapidly, with production amounting to 451.799 tons in 2014, an increase of 5.5 percent from 2013. Chinese gold production has been the highest in the world for eight consecutive years. As a result, more than 2.45 million tons of cyanidation tailings are estimated to be discharged into tailings ponds every year (Li et al., 2010; Lv, Ding and Qian et al., 2015; Wang et al., 2015; Zhang, Li and Yu, 2013; Zhang, Li and Yu, 2012), and approximately 300 million tons of cyanide tailings are stockpiled in China, with the potential to cause serious environmental pollution as well as death to wildlife (Adams and Lloyd, 2008; Donato et al., 2007; Hewitt, Breuer and Jeffery, 2012; Velasquez-Lopez et al., 2011; Stephen et al., 2009; Zagury, Oudjehani and Deschenes, 2004). Concerns over cyanidation tailings are not exclusively environmental but also economic, as tailings occupy considerable land area, and tailings storage facilities increase the production costs of gold enterprises (Donato et al., 2007). Tailings often contain other valuable metals such as zinc, lead and copper. For example, the cyanidation tailings of Gaoyao Hetai Gold Plant in Guangdong Province contain 2.5 percent copper (Cu), 0.31 percent lead (Pb), 0.23 percent zinc (Zn) and 15.36 percent iron (Fe) (Shi, 2008), and the tailings of Tianshui Gold Plant in Gansu Province contain 1.94 percent Cu, 5.96 percent Pb, 0.27 percent Zn and 24.62 percent Fe. Cyanidation tailings have therefore been increasingly viewed as a secondary resource rather than waste."

Jan 1, 2016

By Raymond E. Riethmann

El clasificador de espiral fue diseñado originalmente para circuitos cerrados de molienda. Desde entonces se ha aplicado con éxito a otros trabajos de clasificaci6n donde se necesita realizar un corte de dos productos. Inherentemente a las cualidades especiales de este cla- sificador está especialmente preparado para: clasificar, lavar, o agotar materiales tales como minerales, roca fosfática, arenas, carbbn, conchas de ostra y sales fosfáticas. Presentamos ahora las características de operation, flexibilidad de diseiio y líneas maestras para una apropiada aplicación.

Jan 1, 1982

By K. J. Shoop, S. J. Ripke, T. C. Rao, T. C. Eisele

This study investigated the use of a 7.6-cm inside diameter, 344.2-cm-tall horizontally baffled column to reduce the ash content of a low-sulfur bituminous coal. Tests were carried out to determine how the baffled column responded to changes in feed rate, reagent dosage and feed quality. The tests were also carried out to compare the columns performance to a conventional column installation in an operating plant. In this paper, the results of this investigation are reviewed and discussed.

Jan 1, 1999

By V. P. Keran, K. Leung

Two 32 foot x 14% foot, 6.4 MW autogenous mills have been installed in the Mount Isa Mines Copper Concentrator to replace the fine crushing plant, fine ore bin, rod mills and primary ball mills. This paper describes the reasons for the change, the rationale for the new circuit design and configuration, the design and scale-up processes used to size the mills, considerations for the installation of large mills inside an operating concentrator and some early operating data.

Jan 1, 1992