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By A. C. A. Howe, J. C. Rowntree

"The Bernie Lake pegmatite near Lac Du Bonnet in southern Manitoba is a complexly zoned pegmatite containing several lithium-bearing units in addition to the western world's largest known reserve of cesium. The pegmatite forms a flat-lying ellipsoidal body within an east-west-trending Precambrian amphibolite. The pegmatite enclosed by this vertically schistose amphibolite lies near the eastern tip of a granitic intrusive. The relationship of this intrusive to the pegmatite is obscured by Bernie lake. To date, the pegmatite body has been delineated aver an area of approximately 80 acres; it attains a maximum thickness of 280 feet. Several distinct zones, including three assemblages of economic importance, comprise the pegmatite itself. The combined spodumene and lepidolite assemblages provide a recoverable defined lithium ore reserve of almost 5 million tons averaging more than 2 per cent lithium oxide. The recoverable cesium ore of the pollucite assemblage provides 300,000 tons averaging more than 20 per cent cesium oxide; this represents more than half of the western world's pollucite reserve. The Bernie Lake pegmatite deposit, owned by Chemalloy Minerals Limited, is well located with respect to the growing United States markets, and its reserves of cesium are large enough to enable it, under favourable economic circumstances, to become the major producer of this metal in North America."

Jan 1, 1967

By Jafar Khademi Hamidi

The Zagros long tunnel is one of the main components of Sirvan water transfer project in western Iran. It is approximately 48 km in length and consisted of two lots. The second 26 km lot of this tunnel is under construction by a 6.73 m diameter double shield (DS) TBM. The tunnel passes through several formations with wide range rock mass qualities. During the tunnel alignment, changes in rock quality were highly frequent from poor to very good. The encountered geological conditions required TBM operation to change frequently from hard rock to soft, dry to flowing, sticky to nonsticky ground (and vice versa), more often than expected. In the course of tunneling, the machine has encountered nearly many adverse geologic conditions. The most important problems have been sudden high volume water inflow into the tunnel, sticky ground, and gas seepage, all of which resulted in reduced TBM advance rates. This study will high-light two difficult ground conditions including large water ingress and sticky ground and also the related problems encountered by the TBM along 8 km of excavated tunnel. In sticky grounds, cleaning of the clogged cutter head caused many delays and contributed to additional downtime. Application of some operational modifications, including decreased TBM thrust showed satisfactory results in such cases. While reduced thrust resulted in reduced penetration rate, but the overall TBM advance was greatly improved by the increase utilization rate and elimination of down time related to cleaning of the head. To cope with high water inflow, application of preventive measures such as pre-grouting has proved to be a more efficientsolution. The sealing of ground water inflow also decreased seepage of dangerous H2S gas and other chemicals such as hydrocarbons accompanying the groundwater.

By B. Dyck, L. Verhelst

"Colloidal silica in Key Lake’s Solvent Extraction (SX) feed solutions has presented an operational problem for the mill throughout its history. The colloidal silica stabilizes aqueous continuous emulsions, resulting in elevated solvent losses and operational downtime. Through the years, many attempts have been made to solve this problem, but no viable solutions were found. By revisiting an idea dating back to the 1979 feasibility study and re-evaluating it under current operating conditions, a practical solution was achieved. This paper discusses Key Lake’s history around colloidal silica removal, starting with coagulation using a polyethylene oxide polymer (PEO), and ending with coagulation using a polyethylene glycol (PEG) polymer. The results of a mill trial using POLYSIL® RM1250 introduced at doses up to 300 ppm into the counter current decantation (CCD) circuit to clarify SX feed solutions are discussed with a focus on the benefits to SX.INTRODUCTION Colloidal silica has historically been a significant operational problem in the Key Lake mill. Silica originates from clays in the ore as well as concrete backfill intermixed with the ore resulting from the mining method used at Key Lake’s ore source, the McArthur River mine. The silica is dissolved as silicic acid into solution in the mill’s sulphuric acid leaching circuit. Once in solution, silicic acid polymerizes (Hearn, Smethurst, & Boskovic, 2016) forming a fine suspension of stable colloidal particles. These silica colloids are unaffected by flocculants and sand filtration reporting to the pregnant leach solution (PLS) as a fine turbidity in solution. Silica concentrations typically ranged from 700 to 1200 mg/L Si in the PLS fed to SX. Throughout Key Lake’s history, silica interactions in the Solvent Extraction (SX) process have made SX a mill bottleneck and a source of significant reagent costs."

Jan 1, 2018

By L. Bergkvist

"History can provide many answers with regard to what today’s mining industry looks like and how we got to where we are today. It has always been self-evident that safety has to be given the highest priority and, throughout history, many mine workers have been injured, become ill and have even sacrificed their lives due to the way in which attempts have been made to extract the ore, often due to ignorance of the dangers being faced. In more recent stages of history we have seen certain dangers being compensated by means of higher wages and bonus systems in order to have the work carried out: one example of this is when the rock heating method was employed and the men who first went underground to put out the fires that were burning, were paid extra. The working conditions, to which these people were exposed, with smoke-filled closed spaces, shortened their life expectancy considerably and today we can ask ourselves whether it is really possible to value these efforts just by higher wages. In all mines worldwide the working environment has been improved and many mining companies have a zero vision where work-related injuries and accidents are concerned. Despite this, incidents of varying severity still occur and a continuous improvement process and ongoing training is necessary in order to constantly minimise risks and improve the working environment. Atlas Copco takes this into account in all its development and we not only review our own production units but also the needs of our customers, with regard to the machinery that is produced in order to cater for customers’ safety and production objectives. Underground mining probably started at the beginning of the 11th century when people with modest tools tried to extract ores that were present in the bedrock. Methodology has developed enormously over the years with a strong focus on increased efficiency and higher production. In different parts of the world the development is driven forwards at different rates depending on which controlling factors are regarded as necessary. Political decisions, profit goals and productivity have partly controlled the development, but the greatest factor where improvement is concerned still remains with increased understanding of the totality. During more than 1000 years since underground mining has been conducted, all individuals at all levels have constantly improved their expertise and the human element has been of great importance with regard to the development that has been made, even though technology often occupies a leading role when we describe the improvements made."

Jan 1, 2011

By Horatio Sam-Aggrey, Margot Hurlbert

Small Modular Reactors (SMRs) have been touted as having the potential to spearhead a nuclear renaissance. Proponents of this view cite the relative advantages of SMRs over larger nuclear plants as reason for their optimism. Some of these merits include potential economies of mass production deriving from modular factory production, enhanced safety features, the ability to locate reactors in remote areas, and reduced requirements for technical workforces to install and maintain SMRs. Despite the optimism surrounding SMRs, nuclear power is still a contentious issue for many Canadians. The growth of nuclear power remains adversely affected by concerns over issues such as: the health and safety consequences of nuclear power generation, environmental impacts, proliferation of nuclear materials, terrorism, and radioactive waste disposal (Organisation for Economic Co-operation and Development (OECD) and Nuclear Energy Agency (NEA), 2010). Personal values, past nuclear accidents, and lack of trust in the industry are other factors influencing attitudes toward nuclear energy (IAEA, 2005). In Canada, three main areas where SMRs could be used have been identified. These include: a. Traditional, on-grid power generation, especially in provinces looking for zero-emissions replacements for CO2-emitting coal plants. B. Remote off grid communities that currently rely on diesel or fuel oil power generation. There are 279 off-grid communities in Canada, many of them being Aboriginal communities (NRCan, ND). Notably, all communities in each of Canada’s three territories qualify as remote. C. Resource extraction sites, such as mining and oil and gas extraction sites. Many of Canada’s principal producing mines and active mineral exploration projects are located within close proximity of Aboriginal communities. Any proposed implementation of small nuclear plants would, require the support of the local population, which is largely Indigenous in the northern regions. The possible deployment of SMRs raises important issue relating to consultation and accommodation of Aboriginal concerns regarding potential SMR deployment. This is especially pertinent given Canada’s pending implementation of the provisions of UNDRIP. One of the provisions of UNDRIP that has attracted a lot of attention is the one on Free Prior and Informed Consent (FPIC). Drawing on previously published information, this paper discusses some of the challenges posed by FPIC for the deployment of SMRs. The next section outlines the provisions of FPIC and its implementation in the Canadian context. Section 3, details some of the challenges posed by FPIC to the deployment of SMRs, while Section 4 provides some concluding comments.

Jan 1, 2020

By George Biro, Christoph Mueller

A number autonomous operations is in place in several, mainly in fenced areas, where safety is assured by locking off the entire area for other traffic. However autonomy can be brought much further if functional safety is assured and a real mixed traffic of autonomous and manually operated vehicles is possible. MobileTronics has created a modular software and control framework for autonomous machines. The paper covers application examples in which the deterministic object recognition in combination with probabilistic algorithms and sensors is used as a basis for functional safe certification of mixed traffic autonomy.

Jun 25, 2023

By J E. Wajon

This paper discusses the background, requirements, need and content of plans for management of drinking water self-supplied to mining-related operations, including construction camps, especially in remote areas of Western Australia. The paper discusses the importance of cooperation between regulators, the mine site operator and the consultant in preparing a plan fully compliant with the Australian Drinking Water Guidelines to protect the quality and safety of drinking water supplied to mine sites. The paper outlines some of the issues that need to be addressed in preparing a drinking water quality management plan, such as hazard identification, risk assessment, the multiple-barrier approach and the concept of critical control points. Data requirements, monitoring, incident management, training and reporting are also covered.CITATION:Wajon, J E, 2013. Drinking water quality management for mining operations in Western Australia, in Proceedings Water in Mining 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By Doris M. Hyde

The 350,000-barrel-per-day Bahamas Oil Refining Co remained closed throughout 1986. Financially troubled Charter Oil Co., joint owner of the refinery with Chevron Oil Bahamas Ltd., agreed in principle to have Chevron assume full ownership in return for canceling debts owed Chevron. Finalization of the agreement was pending at yearend. Burmah Oil Ltd. took more than a $30 million loss on the sale of its interest in South Riding Point Grand Bahama Transshipment Terminal to South Riding Point Terminal Holding Ltd.

Jan 1, 1988

"Liberation is a key requirement for efficient separation in mineral processing. As a consequence of this an understanding of the inherent textural features of an ore is no longer possible since during the process of liberation, texture is destroyed. Knowledge of key textural features, such as mineral grain size and distribution, prior to breakage processes provides the opportunity to understand the textural drivers for ore hardness. Modern characterisation methods, including automated SEM-based techniques, provide the possibility of measuring mineral characteristics at a range of scales. This paper discusses how textural features of two different ore types in a porphyry copper deposit can be measured and interpreted at a number of scales. Standard breakage tests conducted on the ores indicate that one of the ores can be characterised as hard and the other as soft. The impact of mineral grain size and the presence and scale of vein type structures in the two ores have been used to determine the extent to which these features influence ore hardness.INTRODUCTIONIn order to effectively convert ore into metal, knowledge of both the processing stages and the characteristics of the ore are essential. Prior to the advent of technologies that enabled the fundamental understanding of the sub-process at each stage of processing and the measurement of appropriate ore properties the most effective way to understand how an ore would respond to a process was to put it through that process, for example the way to determine how an ore would break was to first break it. Existing comminution models seek to predict the size distribution of rock fragments as the result of applied energy based on knowledge of the rock strength. It is common for these models to consider the rock as homogeneous and despite providing important data for the design and optimisation of industrial comminution circuits these models are only applicable within a narrow range of operation. In order for reliable predictive models to be developed that account for the inherent ore characteristics, a step change is required in the type of measurements that are carried out to characterise an ore and the type of data that is extracted and used as model inputs."

Jan 1, 2016

By Xiaozhu Chen, Qi Ping, Pu Yuan, Qinyong Ma

"In order to investigate the fractal feature of coalmine deep rock fragments under impact loads, variable cross-section split Hopkinson pressure bar apparatus, 50 mm in diameter, was adopted to conduct impact compressive test for rock specimens from -962m deep coalmine. Various impact pressures, such as 0.3, 0.6, 0.9 and 1.2MPa, were selected to implement different loading rates. Sieving statistical analyses were conducted for rock fragments after being impacted, and the particle size distribution of broken rock in various loading rates were calculated with the fractal method and then the corresponding fractal dimension was obtained. Test results shows that there is a good self-similarity and fractal feature in fragments distribution of deep coalmine sandstone under impact loads. The fractal dimension of fragments is between 1.9 and 2.7. The research also indicates that there is an approximate power relationship between dynamic compressive strength and fractal dimension, and a strength power relationship between fractal dimension and average strain rate. Moreover, there is a linear relationship between fractal dimension and specimen absorbed energy. The rock fractured process can be quantitatively described through fractal dimension, which can reflect the deep rock broken degree and is an ideal index to evaluate the distribution of rock fragments.INTRODUCTIONBroken rock is one of the most basic processes in mining operations, rock fragmentation has always been an important index to evaluate rock breaking effect (Xu & Yu, 1984). Macroscopic fragmentation of rock material is the final results of continuous development, expansion, gathering and cutthrough of internal micro-cracks. This process, developing from microscopic damage to macroscopic fragmentation, is an energy dissipation process and shows fractal characteristics (Xie, 1993). Turcotte (1986) has conducted statistical analyses of fragmentation for different kinds of geological materials under various broken conditions, and arrived at the conclusion that fragmentation distribution is a fractal."

Jan 1, 2015

By K. A. Perry, R. Q. Eades

The University of Kentucky conducted inerting tests and angle of ejection tests on three types of rock dust. A newly developed hydrophobic dust was compared against typical dry and wet dust applications. This new product is designed to alleviate respirable dust concerns for dry dusting and caking issues with wet dusting. Samples for both test types were prepared in a laboratory and subjected to temperature and humidity cycles that are typical of an underground coal mine. Inerting tests were conducted in a 38-L chamber with a 5-kJ Sobbe igniter. Angle of ejection testing was conducted at the University of Kentucky Explosives Research Team’s laboratory in Georgetown, KY. The results of these tests indicate that the newly developed dust has improved results for flame suppression and ejection compared with typical wet dust applications. The significance of these results is discussed with regard to existing respirable dust regulations and the issues associated with caking.

Jan 1, 2016

By Jerry Gagnon, Matt Burr, Timothy Ellis, Abbas Mirza, Larry Webb

"The mechanical properties of RSR anode alloys (lead-calcium-tin, 009+ and lead-strontium-tin) were investigated as a function of time with an objective of developing lead anodes for use in high temperature electrolytic processes such as in copper liberator cells and in cobalt and nickel electrowinning. At a temperature of 70 oC, the mechanical properties of rolled RSR lead-calcium-tin (PbCaSn) alloy currently used in copper electrowinning decreased gradually while the mechanical properties of rolled RSR lead-strontium-tin (PbSrSn) decreased relatively quickly and stabilized at low strength levels. Cast PbSrSn started off as the weakest alloy but its properties remained stable with time. Rolled RSR 009+ anode alloy showed improvement in ageing properties over the other alloys tested. However, its mechanical properties did not stabilize in the study timeframe of 284 days. Further investigations are planned to study the effect of alloying elements on mechanical properties of RSR 009+ anode alloy over several years as a function of time at 70 oC. The mechanical properties will be evaluated to determine the time at which they stabilize. Comparative plant trials with rolled RSR PbCaSn and RSR 009+ will also be performed in copper liberator cells and in cobalt and nickel electrowinning tankhouses to determine their mechanical and electrochemical performance at temperatures of 65-75 oC.INTRODUCTIONLead-based alloys are the primary anodes used in the electrowinning of copper, zinc, nickel, cobalt and manganese from sulfate-based aqueous systems. Lead anode technology has evolved over the years migrating from pure lead and lead-antimonial alloys to the present day PbCaSn alloys for copper and PbAg and PbCaAg alloys for zinc electrowinning (Prengaman, Ellis and Mirza, 2010). It has also migrated from cast to rolled microstructures in search of improved mechanical properties and higher corrosion resistance. Although great strides have been made in the development of new lead anode alloys and production processes for lead anodes to be used in copper electrowinning, the industry still has some unresolved issues. These relate to the necessity of having higher mechanical properties especially for the lead anodes in liberator cells in copper electrorefining and for cobalt and nickel electrowinning as these tankhouses operate at temperatures of 65-75 oC compared to 40-45 oC in case of copper electrowinning."

Jan 1, 2016

By Christopher R. Harris

"Considerations are presented for developing and implementing self-hardening slurry mix designs to be utilized in barrier seepage walls. Slag-cement-cement-bentonite (SCCB) slurries are the primary focus, with some comparisons referenced to the more traditional Portland-based cement-bentonite (CB) slurries. Field and laboratory mixing methods are reviewed, including 1) single sack – single mixer method; 2) bentonite slurry mixer – cementitious addition mixer method; 3) bentonite mixer – grout mixer – CB blending mixer method. Major phenomena associated with the dynamics of barrier wall excavation, such as loss of water from the in-trench slurry and consolidation of in-trench slurry are discussed. Other topics touched upon include sand content effects, fluidizers utilized, and chemical contaminants. The role of higher bentonite to water ratio is reviewed, with demonstration of improvement of filtration properties, and an increase of water retention of the final consolidated product.IntroductionSelf-hardening slurry has been utilized to construct barrier seepage walls for many decades. This is essentially a single-step slurry excavation and backfill process whereby the trench-supporting fluid gains strength over a short period during installation and maintains or develops low hydraulic conductivity. The resulting curing slurry becomes the actual barrier wall as the resultant cement-augmented clay slurry now fulfills the dual purpose of both temporary trench stabilization and final cured-in-place product. This eliminates the requirement and expense of subsequent backfill/slurry displacement operations required in traditional barrier wall installations.Self-hardening slurries have been fabricated using a number of various clays, most commonly sodium bentonite, calcium bentonite, attapulgite, and sepiolite. Perhaps due to plentiful high quality sodium bentonite deposits found domestically, the proven excavation stabilization properties imparted from sodium bentonite slurries, sodium bentonites are typically specified for formulating self-hardening slurries in the US. Cementitious materials utilized most commonly are Portland cement and slag (ground blast furnace slag or GBFS). For the purposes of this discussion, self-hardening slurry having a cementitious of Portland will be referred to as CB. Those having cementitious material of GBFS replacing Portland (partially or wholly) will be referred to as SCCB."

Jan 1, 2016

Large-scale shear apparatus is designed to investigate the shear hehaviour of simulated soft rock joints under constant normal stifmess condition. Regular saw-teeth profiles having inclinations between 9.5" and 26.5" have been tested. The strength envelope based on these test results indicates that predictions made by Panon (1966) are accurate for the lower asperity angles. However, for higher asperity angles, Patton's model overestimates the shear strength especially in the low to medium normal stress range. In contrast, while Barton's model (1973) is realistic for Constant Normal Load (CNL) condition, it seems to be inappropriate for modelling the shear behaviour of soft joints under Constant Normal Stiffness (CNS) condition. An empirical strength envelope for the prediction of peak shear strength of joints is proposed in this study to account for the change in normal stress and surface degradation during CNS shearing.

Jan 1, 1997

By K. Sharman

Quintette Coal Limited (managed and 50% owned by Denison Mines Limited) operates an open pit coal mine located in northeastern British Columbia, in the foothills of the Rocky Mountains. (See Fig. l). Mining commenced in 1982. The mine currently produces 4.75 million tonnes of medium volatile bituminous coal per year from three pits (Mesa, Wolverine and Shikano), using a truck/ shovel operation. (See Fig. 2). Conveyors and trucks transport run-of-mine coal to the heavy media/froth flotation process plan t, where it is cleaned and loaded into rail cars for delivery to the Ridley Island port at Prince Rupert, British Columbia. All coal is sold to the Japanese steel industry under a long term contract. The coal seams mined at Quintette are contained in the Lower Cretaceous Gates Formation. Mineable seam thicknesses vary from 0.6 m to 10 m. The regional structure of the area is typical of foreland fold and thrust belts, with open to tight folds and imbricate thrust faulting. The range of structural features found in the three pits, and their effect on mining, forms the subject of this paper.

Jan 1, 1991

By Rogers Wade

THE Pilares mine of the Moctezuma Copper Co. is situated at Los Pilares de Nacozari, Sonora, Mexico, about 75 mi. (120.7 km.) South of the international boundary and about 7 mi. (11.26 kin.) east of the town of Nacozari de Garcia. It is situated at an elevation of 5000 ft. (1524 m.) in one of the northward trending ridges that form part of the mountain mass that culminates in the Sierra Madre de Mexico. To the east, south, and west, the topography is rugged and diversified; to the north less diversity exists, ranges of mountains rise sharply out of almost level ground and give the basin range structure characteristic of the southwest. The climate is dry, the average rainfall of 15 in. (38 cm.) being confined almost entirely to the months of June, July, and August. The

Jan 8, 1919

By S. N. Titkov

Flotation of halite?new, recently begun to be developed method of processing water-soluble minerals. In the paper the results of studies of the new directions of the application of halite flotation are represented. Studies on the flotation separation of halite and sylvite in the salt solutions of different composition, showed the possibility of the halite flotation realization not only in the carnallite brine (content of salts: MgCl2 25.5% ~ 26.0 %, chlorides of potassium and sodium 5.5% ~ 6.0%), but in the sylvinite brine, which contains 10.5% ~ 10.8% KCl and 20.5% ~ 21% NaCl. On the basis obtained results are carried out experiences on the halite flotation from samples of the converted products of sylvinite ores by flotation method and by the method of the electrostatic separation. It is shown that in all cases it is possible to accomplish effective and selective recovery of halite. The halite recovery into the foam product of flotation makes 80% ~ 90% with an increase in the content of KCl in the cell product of flotation in comparison with a composition of flotation feed: - from the product after the electrostatic separation of ore ? from 76% KCl to 95% ~ 97% KCl; - from the small fraction of ore (- 0.25 + 0 mm) ? from 30% KCl to 60% ~ 64% KCl; - from middlings (intermediate products) of sylvite flotation from 16% ~ 31% KCl to 45% ~ 80% KCl. An increase in the molecular weight of alkylmorpholines increases the selectivity of the flotation separation of halite and sylvite. Halite recovery from small size fraction of ore or/and middling of sylvite flotation with the sub-sequent joint filtration halite product and tails of sylvite flotation allows to reduce considerably expenses for manufacture potash chloride from Pilot-industrial tests for the first time confirmed the possibility of the effective halite flotation in the saturated solutions of chlorides of potassium and sodium (sylvinite brine).

Jan 1, 2014

By G. R. Speich

A cellular precipitation reaction in which cells consisting of an Ni3Ti (DO24) phase and austenite are formed has been studied in an austenitic Fe-30 Ni-6 Ti alloy. The variation of the growth rate and interlamellar spacing of the Ni3Ti cells with temperature has been determined m the range 400" to 975°C; the interlamellar spacing is proportional to the degree of undercooling; the growth rate can be expressed by an equation of the form G = K?T)2 exp(-Q/RT). The habit of the Ni3Ti lamellae is (001)Ni3Ti (111)y;[010]Ni3T2 [010]y. An almost perfectly coherent interface is formed between Ni3Ti lamellae with this orientation rela -tionship and the intervening austenite. This first Ni3Ti cellular product is subsequently consumed by a second cellular reaction of much coarser spacing. CELLULAR precipitation reactions have been studied in copper-base,1,2 Au-Ni,3 pb-sn,4 and iron-base ferritic5,6 solid solutions, and this mode of precipitation has been treated theoretically by smith," Turnbull,8,9 cahn,10 and more recently by bohm.11 In the case of substitutional austenitic iron-base alloys little or no data are available, Cellular precipitation reactions are well known in austenitic nickel-base alloys12,13 but usually these reactions do not proceed to completion because of general precipitation occurring in the matrix, and they have not been studied in detail. Precipitation from an austenitic Fe-30 Ni-6 Ti alloy was studied as part of a larger investigation of the mechanisms of precipitation from substitutional iron-base alloys. This alloy, austenitic at high temperatures, decomposes at lower temperatures by a double cellular precipitation reaction. The first decomposition product consists of alternate lamellae of an Ni3Ti(DO24) phase and austenite. The reaction proceeds to completion, consuming all of the original austenite. This first cellular product is subsequently consumed by a second cellular reaction of much coarser spacing. The first cellular reaction was studied in detail by light and electron microscopy, hardness measurements, and by X-ray and electron diffraction. Interlamellar spacings and growth rates were measured during isothermal aging in the range 400" to 975°C. The orientation relationship between the Ni3Ti and austenite lamellae was determined and indicates that an almost perfectly coherent interface exists between the two phases. This first Ni3Ti cellular reaction is of particular interest because it occurs over such a wide temperature interval. This allows cellular growth rates and interlamellar spacing data to be obtained for much larger degrees of undercooling than reported hitherto. MATERIALS AND EXPERIMENTAL PROCEDURE The Fe-30 Ni-6 Ti alloy was prepared from electrolytic iron, Mond nickel shot, and sponge-purity titanium* by vacuum melting in a zirconia crucible

Jan 1, 1963

By A. Yehia

Fluoride activation has been evaluated by Hallimond-tube flotation of collophanite in terms of fluoride concentration, conditioning time, pH, and temperature. The results reveal that efficient oleate flotation of collophanite can be achieved by fluoride activation. Fluoride adsorption by collophanite as a function of fluoride concentration, temperature, pH, and crystal structure suggests that, at low fluoride concentration, a fluoroapatite-type compound may form on the collophanite surface by chemisorption of fluoride ions at calcium sites; at high fluoride concentration, calcium fluoride ap¬pears to form at the collophanite surface invovling a surface-precipitation phenomenon. The formation of CaF2 on the surface of fluoride-treated collophanite is further substantiated by the FTIR spectroscopic measurements, which clearly shows a metathetic exchange with phosphate from the collophanite lattice during surface precipitation process.

Jan 1, 1986

By Shiwei Wang, Ziwen Li, Chenhu Zhang, Peng Chen, Chengyong Wang

Accurate prediction of the partition coefficients in coal gravity separation is key to improving the preparation efficiency of coal and promoting its clean utilization. In China, the approximate formula method (AFM) has been applied to the calculation of coal gravity separation partition coefficients for decades, but its accuracy is limited. To improve the accuracy of the predicted partition coefficients, and thus the product yield of coal preparation plants, the present study proposes a modified hyperbolic tangent model to derive direct calculation formulas for the heavy medium and water medium separation partition coefficients. Four groups of coal samples were used to verify the accuracy of the direct formulas, and their predictions were compared with those of the AFM. The results showed that the partition coefficients and partition curves predicted by the direct formulas were closer to the actual values than those predicted by the AFM. Further, when the cleaned coal ash content was basically the same, the cleaned coal yield predicted by the direct formula was lower than that predicted by the AFM, and was also closer to the actual value. These results demonstrate that the direct formula produces more accurate results compared to the conventional AFM. As this formula has a reasonable theoretical basis, is simple to apply, and produces accurate results, it is expected to help improve the design and management level of coal preparation plants.

Oct 15, 2022