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By F. J. Hurst

Phosphate rock, which is a prime source of phosphate used in fertilizer manufacture in the United States, contains uranium. In general, the uranium content of the rock increases with the phosphate content and most high-grade phosphate deposits (>30% P2O5) contain 0.01- 0.02% U3 8. The large tonnages of rock being mined represent a significant potential source of uranium that lends itself to recovery as a by-product of the wet-process phosphate industry. For example, in 1953, the U. S. Geological Survey estimated that recoverable phosphate reserves in the U. S. totaled about 5 billion tons and contained 600,000 tons of uranium. I This estimate did not include any rock from North Carolina which has since been estimated at about 2 billion tons. For the most part, the known, economically mineable U. S. reserves - estimated at about 7 billion tons - are concentrated in a few areas: 43% in the western states of Idaho, Montana, Utah and Wyoming; 28% in each of Florida and North Carolina and less than 1% in Tennessee. In the past, Florida has supplied about 80% of the total U. S. production, practically all of which is land pebble phosphate. All forecasts indicate increased production rates from North Carolina and the western states.

Jan 1, 1976

By Damien Bretall, William Fourney

Due to the changing face of warfare there is an ever growing need to protect the underside of combat vehicles from mine blasts. This paper presents a new method to better characterize the pressure profiles experienced by a plate as the blast develops. The explosive deformation of a small-scale plate was recorded using synchronized high-speed digital cameras, and then analyzed using 3D Digital Image Correlation software. Time-varying pressure profiles were input into an axisymmetric FEM simulation by fitting curves to data obtained from tests using Kolsky bars to measure pressures. These were then modified to find possible profiles that produce the measured deformations. It was discovered that the final deformation cannot be determined from only total impulse or peak pressures, and that it is very sensitive to the time and spatial decay of the pressures.

Jan 1, 2009

By M. K. Mohan

During the processing of metals like Cu, Ni, Co, large quantities of solutions, which contain co- products such as Sb, Cd, Pb etc. are generated. These solutions if processed to recover the metals help in conservation of metals as well as environment preservation. The present study was taken up to recover antimony from process solutions using zeolites. The effect of pH of the solution, time and type of zeolite viz., chabazite, mordenite, erionite and clinoptilolite on the sorption of antimony was investigated. Rate of sorption increases with pH and about 77-pct. antimony sorption was observed with chabazite at a pH of 6. Optimal conditions were established for the maximum recovery of antimony fiom process solutions. The mechanism of sorption for Sb was proposed in terms of adsorption and intraparticle diffusion. The calculated adsorption constants from Langmuir and Freundlich equations indicated that the adsorption of antimony on chabazite was strong.

Jan 1, 1999

Aberfoyle sought to reduce Hellyer project development risk to a greater degree than usual. Consequently the ore reserves estimate and feasibility study were particularly comprehensive. A detailed ore reserve study was completed based on extensive drill core and underground sampling, large scale pilot plant work and a detailed feasibility study. Leading external consultants were used for advice on commercial matters which impact on ore reserves and to audit major technical conclusions, including the results from pilot plant work and the ore reserve estimate. Other project risks were diminished by negotiating a State agreement covering security of title, royalty formula and environmental management procedures, by obtaining sales contracts, and by analysing Hellyer's position on an industry cost curve. The task of financing the project was much simplified by the extent and quality of information available from the ore reserves estimate and feasibility study report.

Jan 1, 1990

By L. Yuan, A. C. Smith

MFIRE, the mine-fire simulation program of the U.S. National Institute for Occupational Safety and Health (NIOSH), is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines. MFIRE has been used by U.S. and international companies to simulate fires for planning and response purposes. It is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence, such as changes in ventilation parameters; external influences, such as changes in temperature; and internal influences, such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the former U.S. Bureau of Mines in the 1970s, several updates have been released. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE’s outdated Fortran programming language was replaced with an object-oriented C++ language and packaged into a dynamic-link library. However, the MFIRE 3.0 release included no change or improvement to the fire-modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire-modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of the t-squared fire as a new fire-source model and the ability to include available heat-release-rate versus time data, the addition of a moving fire source for conveyor-belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke-rollback phenomena. All of the improvements discussed in this paper will be included in MFIRE 3.1 and released by NIOSH in the near future.

Jun 1, 2016

By Z. R. Llanos

This paper presents a review of industrial and experimental processes for the recovery of molybdenum, vanadium, nickel, cobalt and aluminum from spent hydrotreating or hydrodesulfurization catalysts. Numerous processes have been developed in a laboratory and pilot scale. However, worldwide, there are only four well established commercial facilities currently in operation. The installed capacity of these facilities exceeds the availability of spent catalysts and may be sufficient to assimilate future increases of spent catalysts. Despite liability risks; significant quantities of spent catalysts are still being landfilled. Changing regulations that may affect the future handling and disposal of spent catalysts are also reviewed.

Jan 1, 1995

By Lawrence Nordell

A Conjugate Anvil-Hammer Mill (CAHM) has the potential to replace conventional crushers and SAG mills, with their respective conveyors and stockpiles, in a SABC circuit. It may improve comminution circuit efficiency by 100%. CAHM compresses rock in a more efficient way, similar to 19th century stamp mills, which follows the fundamental research of Schönert (1990 & 1996). CAHM efficiency is being proven through the use of ROCKY (2011) Discrete Element Method (DEM). ROCKY features allow it to simulate realistic comminution. CAHM is customizable with many geometries that are rock-property specific. ROCKY?s wear modeling compliments the structural integrity of the design.

Jan 1, 2012

By Renato G. Bautista, David C. Lindholm

The results of scale-up studies on a continuous, multistage horizontal mixer-settler extractor are presented. The chemical and mechanical system involves the separation of lanthanum from a mixture of rare earth chlorides using di(2-ethylhexyl) phosphoric acid as the solvent and dilute HCl as a scrub solution in a bench scale extractor. Each stage has a hold-up of 2.6 l. A single stage unit is utilized for scale- up studies. Results are obtained on four sizes of geometrically similar units, the largest being six times the volume of the original bench size. A unit operations technique is chosen so that mixing and settling can be examined independently. Variables examined include type of continuous phase, flow rate of inlet streams, and power input to the mixer. Inlet flow-rate ratios are kept constant for all tests. TWO potential methods of unbaffled pump-mixer scale-up are explored; the maintenance of constant impeller tip speed and constant power input. For the settler, the previously successful method of basing design on constant flow-rate per unit cross- sectional area is used.

Jan 1, 1977

By J. M. Mutmansky

Introduction Since the Hardy Cross numerical algorithm was applied to the solution of mine ventilation networks, numerous developments have taken place in ventilation network analysis procedures. The Newton-Raphson method, the linear theory method and the second-order approximation method are three of the additional approaches that have been applied. The efficiency of a ventilation network analysis procedure depends not only on the method of solving the system of equations derived from ventilation networks but also on the method of deriving the equations through selection of the meshes. This paper investigates the impacts of three mesh selection methods on the efficiencies of four ventilation network procedures. The minimum-resistance spanning tree method is the most popular procedure for selecting meshes. The shortest-path method was suggested by Epp and Fowler (1970) for improvement of the Newton-Raphson method. The minimum-resistance-path method is suggested here as the third method of selecting meshes. The effects of these three methods on the Hardy Cross method, the Newton-Raphson method, the linear theory method and the second-order approximation method are analyzed in this paper. These network analysis methods have been summarized in the paper by Kim and Mutmansky (1991). Mesh selection methods A procedure for mine ventilation network solution based on mesh equations typically consists of two steps: • the mesh selection step and • the network solution step. The mesh selection step establishes a set of independent equations to solve the network. The resulting equations are nonlinear. One method of solving nonlinear equations is to linearize the equations and iteratively solve these linear equations. The four analysis methods previously discussed in this paper use this approach. The linear equations required for solution can be written in matrix form as: P•dQ = dF (1) where P is the pseudo-resistance matrix, Q is the quantity matrix, and F is the Jacobian matrix (Kim and Mutmansky, 1991). The efficiency of the solution method depends on the characteristics of the P matrix, which in turn depend on the method of selecting meshes. To understand the impacts of the mesh selection methods on the efficiency of the ventilation network analysis procedures, the characteristics of the P matrix must be understood first. The diagonal elements of the P matrix, m in number, are the sums of the pseudo-resistances of the branches contained in the m meshes necessary for solution. The off-diagonal elements are the sums of the pseudo-resistances of the branches shared by two meshes. For example, P12 (first row, second column element of the P matrix) is the sum of the pseudo-resistances of the branches common to mesh 1 and mesh 2. When solving the system of equations expressed in Eq. (1), three of the iterative procedures (the Newton-Raphson, the linear theory and the second-order approximation methods) use the direct factorization method (Burden and Faires, 1985) on the P matrix. When the direct factorization method is used, the computational efficiency is enhanced by larger diagonal elements and a sparser P matrix. Generally, the sparsity of the P matrix is more important than the size of the diagonal elements. There is no known mathematical method of predicting the efficiency of these procedures, but heuristic methods can be used to study the efficiency. The Hardy Cross algorithm applies the Gauss-Seidel method of splitting the P matrix and applies the Newton-Raphson procedure. The efficiency of the Hardy Cross method depends on the spectral radius of the matrix[[D-L]-1U], where D is the diagonal, L is the lower triangle and U is the upper triangle of the P matrix for the Newton-Raphson method (Ortega, 1972). The smaller the value of the spectral radius, the faster the convergence. As with the other three methods, larger diagonal elements and a sparser matrix aid in faster convergence. With the Hardy Cross method, however, the size of the diagonal elements is more important than the sparsity of the matrix. Remembering that each of the diagonal elements of the P matrix is the sum of the pseudo-resistances of the branches in a mesh and that each off-diagonal element is the sum of the pseudo-resistances of the branches shared by two different meshes, the following strategies can be used: • Avoid having branches with larger resistance values shared by multiple meshes. This increases the size of the diagonal elements and reduces the chance of off-diagonal elements being large.

Jan 1, 1993

By N. S. Aouad

"Gaseous explosions are one of the most hazardous incidents in process and mining industries. Experimental research in this area is shown to be high risk and expensive. Computational Fluid Dynamics (CFD) techniques are reasonable alternatives to experiments; specifically when testing large scale gaseous explosions such as methane explosion in underground mines. The dimensions of a confined space where explosions could occur vary significantly. Thus, the scaling effect on explosion parameters is worth to be investigated using CFD tools. In this research paper, the impact of scaling on the explosion overpressures is investigated by employing two scaling factors. These two factors are the Gas-fill Length scaling factor (FLSF) and the Hydraulic Diameter scaling factor (HDSF). The combinations of eight HDSFs (1, 2, 4, 8, 16, 32, 64, and 100) and five HDSFs (0.5, 1, 2, 4, and 8) will cover a wide range of space dimensions where flammable gas could accumulate. Experiments were conducted to evaluate the selected premixed combustion and turbulence models. Large Eddy Simulation (LES) turbulence model was used because it shows accuracy compared to the widely used Reynolds’ averaged models for the scenarios investigated in the experiments. Researchers also simulated methane explosions in both deflagration and detonation regimes using different numerical schemes. Three major conclusions can be drawn from the simulation results. (1) The overpressure increases with both FLSF and HDSF within the deflagration regime; (2) in an explosion duct with length to diameter ratio greater than 54, detonation is more likely to be triggered for stoichiometric methane/air mixture; (3) overpressure increases as an increment hydraulic diameter of a geometry within deflagration regime. INTRODUCTION The most typical category of gaseous explosion accidents is methane explosion accidents in the mining industry. It normally leads to significant economic loss and massive amount of casualties (McPherson, 1993). It could occur in unconfined spaces, such as combustion due to flammable gas leakage, as well as confined spaces, such as inner-combustion in process equipment and methane explosions in airways of underground mines. Gaseous explosions in confined spaces are more intensive compared to unconfined spaces provided that the total energy of explosives is the same. In addition, explosion characteristics are also affected by the geometry of a selected confined space. The size of confined spaces commonly encountered in process and mining industries could differ as much as an order of four (Catlin & Johnson, 1992). A better understanding of the scaling effect on gaseous explosions could contribute to explosion mitigation and prevent operation activities within high risk regions. This research paper has investigated this scaling effect and its impact on explosion propagation. The approach to investigate explosions is either experimental or numerical. Large scale explosion experiments are often costly and dangerous (Catlin, 1991; Zhang, Pang, & Zhang, 2011). Lab scale experiments and numerical methods are common alternatives. However, it is not yet clear if the findings in lab scale experiments can be used to represent the explosion characteristics or not. On the other hand, CFD modeling has been used to simulate chemical combustions and, thus, can be used to evaluate the scaling effects in methane explosions."

Jan 1, 2015

By A Atkins

Six recent case studies were selected based on the eight main causes of mine disasters (Table 1; Quinlan, 2014) and where credible information sources, such as Royal Commission Reports, Coronial Investigations and textbooks, were available. The six case studies are listed below. Details are available via this link or the conference PowerPoint accompanying this paper. 1. Beaconsfield, Tasmania – 2006 Fall of Ground/Seismic Event (Chandler, 2009; Melick, 2007; Wright, 2012). 2. Bingham Canyon, USA – 2013 Manefay Slide (Ross, 2017). 3. Bronzewing, WA – 2000 Hydraulic Fill Inrush (Hope, 2002). 4. Brumadinho and Samarco, Brazil – 2015 and 2019 Tailings Storage Facility (TSF) failures (Bowker, 2019; Darlington et al, 2019; Demajorovic, Lopes and Santiago, 2019; Morgenstern, 2016). 5. Northparkes, NSW – 1999 Cave Air-blast (Bailey, 2003; Hebblewhite, 2003). 6. Pike River, NZ – 2010 Methane Gas Explosion (Macfie, 2013; Panckhurst, Bell and Henry, 2012.

May 5, 2022

By H S. Welideniya, K Ekanayake

Carbon rich graphite deposits found in Sri Lanka are of inorganic origin and they occur as narrow steeply dipping veins. The vein width of these deposits varies from a few centimetres to metres, with an average vein thickness of 1 m. It is believed that the carbon rich fluid intruded into fracture zones under high pressure and the temperature has crystallised into graphite. This process has also generated many minuscule graphite veins centred on main mineralisation, which has reduced the host rock overall rock mass rating. These discontinuities could also be considered as joints with graphite infill. Graphite mining at Bogala Mines, Sri Lanka is a unique example of narrow vein mining faced with numerous wall stability issues resulting from weak graphite infilled joints.The Bogala vein type graphite orebody has an average vein width of 1 m. Overhand cut-and-fill mining method is used for stoping. The stope consists of two boundary winzes for material handling, access and ventilation. Mining is done on the strike of the vein and the average mining slice height is 2 m. A void to the height of one mined slice is left below the mining level during mining. Waste rock resulting from vein blasting and mine development is dropped into this void as fill rock. Any void height left greater than a single slice height will increase stresses in the stoping zone. This will increase formation of rock blocks and their effective separation from wall rocks. Split miniscule veins occurring around main mineralisation intensifies rock block formation in an environment of mining induced stress release. Consequently, any rock blocks sliding into stopes on graphite infilled joints will behave under constant normal stiffness (CNS) conditions and their shear strength will converge rapidly towards remoulded shear strength of graphite alone. Unlike with general infill deposited in joints, graphite has a very low friction angle and with its slippery nature, a small thickness may affect in great deal to reduce joint shear strength.In addition to immediate filling of excavated voids, controlled vein blasting and spot bolting have improved mine safety. Furthermore, rock bolts connected to each other through iron plates and anchored to anchor bolts installed in non-fractured solid rock are practiced to stabilise rock falls and wedge failures in narrow vein graphite mining. These practices have significantly contributed to safe mining without any rock bursts and catastrophic failures.CITATION:Welideniya, H S and Ekanayake, K, 2012. Challenges faced by narrow vein graphite mining and influence of graphite infill on wall stability, in Proceedings Narrow Vein Mining 2012 , pp 71-76 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

By Hayel M. El-Naggar, Marawan M. Shahien

"Large capacity piles are important type of foundation elements that are needed in case of high column loads such as in tall buildings with large span between columns. In many projects, especially if the designer uses the concept of one pile supporting one column (Hamza, 2003a & b). The axial capacity of the large bored deep foundations can be further increased by grouting the shaft skin and the base of the pile. The increase in the capacity of the piles due to grouting can be tremendous. Thus grouting appears as an ideal solution for achieving more reliable foundation and greater savings (Littlechild et al., 2000). A data base of pile load tests of instrumented grouted piles is under development in a major study aiming to propose a simple method to estimate the axial capacity of large bored grouted piles. The data base include pile load tests from projects constructed in Egypt and abroad. The main goal of this paper is to analyze pile load test(s) from one project. The tested deep foundations included 1.2 m diameter and 1.5 m diameter piles and a barrette of size 1.0mx2.8m. The instrumentation of the tested piles and barrette allowed for the separation of skin friction and base contributions to the axial load. Further, the contribution of the skin friction of every layer along the pile shaft could be identified. The results of the analysis clarified how base and shaft grouting increased the axial capacity of the pile and decreased the settlements for certain load level compared to conventional un-grouted piles installed under similar conditions.INTRODUCTIONIn recent years, significant research has been carried out to develop new techniques which are suitable to withstand problems in major projects such as high applied loads in high rise building, large spans structures projects and structures designed using the concept one pile supporting one column (Hamza, 2003a & b). Base and shaft grouting of piles are one of these new techniques which aim at decreasing the settlements and increasing the capacity of the pile under axial load that became major requirements in large projects (Stocker, 1983; Mullins et al., 2001; and Hamza, 2015).Base grouting consists of injection grout under pressure at the base of the pile after the concrete is sufficiently hard. Field evidences showed that the ultimate end bearing of base-grouted piles could be as high as 1.5 that of non-base-grouted bored piles (Suckling and Eager, 2001). Further, field evidences was provided by Shahien and El-Naggar (2015) that showed an increase in end bearing resistance due to base grouting reached to 2 to 3 times that of non-base-grouted bored pile. On the other hand, shaft-grouting causes increase in the soil density in the zone which had been disturbed by the pile construction and thereby improves the shaft resistance of the pile. Field measurements by Gouvenot and Gabaix (1975), Stocker (1983), Robson and Wahby (1994), Troughton and Stocker (1996), Byrne et al. (1998), Joer and Randolph (1998), Hamza and Leoni (1998), Littlechild et al. (2000), Hamza and Ibrahim (2002), Hamza (2003 a&b), Hamza (2015) and Shahien and El-Naggar (2015) showed that the shaft resistance of grouted piles could be nearly 1.5 to 5 times that of non-grouted piles."

Jan 1, 2017

By Lloyd M. Kniffin

[This paper is one of series being prepared by the United States Bureau of Mines on mining methods, practices, and costs in the various mining districts of the United States. It describes the mine of the Hanover Bessemer Iron & Copper Co. at Fierro, Grant County, N. M., which is the only operating iron mine in the southwestern part of the United States. This mine is in a district noted for the great variety of ores that it produces. Within a small area, as shown is Figure 1, there are noteworthy deposits of nearly all the common metals. The ore occurs in lenticular masses dipping at about 50°. An underhand stoping method has been developed that requires but a very small amount of handling of ore. As the ore is very irregular in iron content and also in the distribution of the impurities--chiefly sulphur, silica, and magnesia--a method has to be used that will permit selective mining and will also allow ore and waste to be taken out separately as conditions change. A magnetic cobbing plant raises the grade of the ore shipped about 10 per cent.]

Jan 1, 1930

By T. Wajima

"A novel carbonaceous immobilizing agent for heavy metal contaminated soil was prepared from rice straw using sulfur immersion and pyrolysis, and the lead immobilization in artificial contaminated soils using sulfur-impregnated carbonaceous material was estimated. The rice straws were cut to 1 cm pieces, and then immersed in 0.1 - 1 M K2S solution for 0 - 24 h to prepare sulfur-immersed materials. The immersed-materials were heated at 400 oC for 1 h in nitrogen gas to produce the sulfur-impregnated carbonaceous material by pyrolysis. The abilities of the product to immobilize lead from aqueous solution were examined to obtain the product with high lead immobilization ability. With increasing K2S concentration, the immobilization ability of the product for lead gradually increases and then above 0.5 M K2S those are almost constant, while 15 min is sufficient for the immersed time to obtain the product with high lead immobilization ability. The product prepared from material immersed in more than 0.5 M K2S solution for less than 15 min has a maximum immobilization ability for lead ion. The lead immobilization using the sulfur-impregnated product is sustainable due to the formation of leadhillite [Pb4SO4(CO3)2(OH)2] and anglesite [PbSO4]. The product can immobilize lead ion in various artificial lead contaminated soils. By mixing artificial lead contaminated soil with the sulfur-impregnated product, the eluted solution became neutral, and the eluted concentrations of lead ion dropped below the Japanese elution standard for soil.INTRODUCTION Soil contamination with heavy metals is a worldwide problem. Accumulation of heavy metals in soils affect soil ecology, agricultural productivity, quality of agricultural products, water resources, and serious health problems for human and animal (Raicevic, et al., 2005). In the United States, for example, approximately 63 % of the sites on the National Priority List (NPL) for the treatment of contaminated soils are contaminated by metals, and lead is the most common metal, found at 15 % of the sites. In Japan, according to a report by the Ministry of Environment, 43 % of the contaminated sites that exceed the environmental quality standards are contaminated by lead compounds. Soil contamination by lead compounds is also prevalent in other developed and developing countries where lead compounds are used extensively in industrial activities without careful contamination management. Lead is a ubiquitous heavy metal pollutant in soils due to their use widely. The primary sources of Pb contamination include industrial activities such as mining, smelting of metals, and the use of Pb-containing products such as paints, lead-acid batteries, bullets, gasoline and pesticides (Cao, et al., 2009). It can damage human nervous (especially children) and reproductive systems (ATSDR, 2007). The high concentration of Pb in the soil poses risks to human and animal health by the leaching of metals from the soil into water and the consumption of edible plants growth in the contaminated soil. Therefore, proper remediation is necessary to reduce metal availability in soil for protecting human health."

Jan 1, 2018

By A Yáñez, P Vallejos, R Grau, J Yianatos

In flotation cells, especially in large flotation units, froth management is a crucial variable that should be considered during the design phase or optimised to improve the performance of existing flotation circuits. This paper presents a simulation evaluation of the effect of launder design on the metallurgical performance of an industrial flotation circuit consisting of five TankCell® e630 (630 m3 ) cells in a Cu rougher duty. This analysis was carried out using a new industrial simulator, which was built on a wide database collected from many industrial concentrators. This tool is currently incorporated into HSC Chemistry® software and allows evaluation of the effect of launder design on mineral froth recovery, water recovery, entrainment, and other variables to be quantified. The industrial flotation circuit was evaluated under different launder design scenarios, considering an actual flotation circuit that includes TankCell® e630 cells for calibration and as a reference (baseline). Firstly, two different designs were evaluated in the full circuit: a standard launder design and a new launder technology. It was found that the new launder technology enabled improvement of the mineral recovery along the circuit, mainly for coarse particles, due to the improvement in froth mineral recovery. Next, the partial upgrade of the launder design along the circuit was analysed. Thus, the new launder technology was evaluated in the first and the last two cells of the bank. The results showed that upgrading the launders in different cells along the circuit delivered an increase in the final recovery with respect to the baseline, with a partial impact on the concentrate grade. However, these changes are less than those when evaluating the full upgrade scenario. A partial launder upgrade either in the first or last two cells of the bank showed similar final recoveries, but the latter enabled a slightly higher concentrate grade (about 1 per cent higher) to be achieved. Finally, the evaluation of launder design using the industrial simulator made it possible to estimate its effect on variables that are not commonly obtained from plant surveys, including froth recovery per particle size, collection recovery per particle size and liberation, gangue entrainment and bubble loading grade.

Aug 24, 2022

By W. Q. Zhao

In order to raise the utilization rate of phosphate resource of Al-Jalamid Mine in Saudi Arabia, a flotation experiment for its phosphate rock was carried out by using WF-01collector that have been produced by Wengfu Phosphate Mine. The results showed that WF-01 collector had extensive adaptability for Al-Jalamid phosphate rock, and the grade of phosphate concentrate could be up to 33% P2O5 mixing the upper, middle and lower beds rock as well as its 80% more recovery.

Jan 1, 2014

By Anderson de Farias Pereira

Estudos recentes sugerem que a produção de nanocompósitos de MgH2 com nanomateriais de morfologia 1D baseados em TiO2 produzidos via moagem reativa promovem aumento significativo na cinética de absorção-dessorção de hidrogênio deste material, o que favoreceria sua aplicação em tecnologias de armazenamento de hidrogênio em estado sólido. A proposta deste trabalho é avaliar o efeito da energia de moagem na integridade das nanopartículas e seu desdobramento nas cinéticas de sorção do material. Para tal, amostras de MgH2 com 5%p. de nanobastões de TiO2 (NR-550) foram produzidas em moinho de bolas planetário a 100, 200 e 300 rpm, respectivamente. Difração de Raios X (DRX) foi utilizada para caracterizar a estrutura cristalina e Microscopia Eletrônica de Transmissão (MET) associada com EDS para analisar o tamanho e morfologia dos catalisadores em meio ao hidreto. Os resultados até o momento indicam que o processo de moagem a 100 rpm não ocasionou variação significativa na distribuição de tamanho e razão de aspecto comparado ao aditivo puro (com valor médio de 35 nm e 2,70 respectivamente). Ensaios de cinética de sorção de hidrogênio ainda estão em andamento.

Oct 30, 2017

The reduction in man's contribution to the Greenhouse effect will only be achieved by a number of small steps. Some steps will absorb carbon dioxide (CO2) from the atmosphere in slightly greater quantities, others will reduce the amount of carbon dioxide generated. This paper deals with the reduction of carbon dioxide by improving the combustion efficiency of petroleum fuels. Until recently most reductions in fuel consumption and air pollution have been brought about through mechanical adjustments to combustion equipment. Since the development of tetraethyl lead, little has been done to chemically modify combustion reactions to improve fuel efficiency or reduce emissions. During the past five years Australian laboratory and field trials with ferrous picrate treatment have demonstrated significant and economic gains in the combustion efficiency of diesel fuels. These studies have revealed that even under ideal conditions in diesel engines, carbon monoxide (CO) momentarily saturates the combustion chamber. This state reduces combustion rates, peak pressure and power and increases the risk of pollution. Theoretical, laboratory and field data are presented which support the mechanism by which the ferrous catalyst accelerates the oxidation of CO to the terminal CO2 thus reducing fuel consumption and the undesirable combustion products accompanying the CO saturation of combustion environments. While this paper deals principally with diesel fuels commonly used in mining operations, the catalytic effect of the ferrous ion is also shown to significantly reduce fuel consumption by petrol engines thereby promising a means to reduce the much larger contributions to the Greenhouse gases by automobiles.

Jan 1, 1989

By X. Xu

This paper presents the research on comprehensive recovery of copper, gold, silver and iron from tailings from high-intensity magnetic separation in Tonglushan Mine. By comparison of experimental results of three flowsheets?regrinding of tailings-conventional sulphidizing flotation, water heating enhanced sulphidizing flotation and acid leaching-sulphidizing precipitation flotation, it is concluded that regrinding of tailings-conventional sulphidizing flotation flowsheet has the best economical and technical performance and practicability. Regrinding and using the mixture of sodium hydroxamate and sodium xanthate are two of the notable technical characteristics of this best flowsheet. The system for comprehensive recovery of tailings has been put into production. It not only can recover the valuable minerals from tailings in Tonglushan Mine, but also can reduce the environmental pollution, resulting great economic and social benefit.

Jan 1, 2014