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By Dale S. Preece, Ruilin Yang

"Air-decking has been used frequently in blasting for many decades. It has been asserted that an air-deckcan alleviate excessive shock pressure from the detonation of a charge thereby producing better energy distribution in a blast overburden, for example. Research on air-decking has been active and various theories have been postulated that mostly support the effectiveness of air-decking for improved blast efficiency."

Jan 1, 2017

By S. J. Pearce

The Bureau of Mines has prepared, as circumstances have dictated, a series of schedules setting forth the minimum requirements that various types of equipment should meet to be considered safe and satisfactory for use under certain hazardous or unhealthful conditions. These schedules cover a wide variety of devices ranging from explosives to electrically operated mine locomotives. This paper discusses the functions and operations of schedules under which respiratory protective devices are tested and approved. It emphasizes that the aim of the Bureau respirator-approval system is to make available to the public respirators that meet definite performance requirements. The responsibility of the respirator manufacturer in pre-testing the device and in maintaining its quality after it is approved are explained. Aid is provided for the user in selecting the proper device for specific application, and a plea is made for better education of all concerned in the proper use of the devices. DISCUSSION Provisions have been made for testing and approving the following types of respiratory protective devices: Self-contained breathing apparatus,2/ supplied-air respirators,3/ gas masks,4/ dispersoid respirators,5/ and chemical-cartridge respirators.6/ These devices are tested at the Central Experiment Station of the Bureau of Mines in Pittsburgh, Pa. Self-contained breathing apparatus is tested by personnel of Health and Safety District B; other types of respirators are tested by the Branch of Health Research.

Jan 1, 1957

By R. Stefaniuk, T. Le, J-Y Huôt, H. Henein

"One of the most important process variables in gas atomization is the gas to metal (G/M) mass ratio as it has a direct effect on the mean particle size of the atomized powder. If this ratio can be controlled during the atomization process, the powder produced would be more uniform and the d50 more predictable. Thus, atomization using a tundish or gravity feed from a crucible would be more stable. In gas atomization, the gas flow rate can be easily monitored; while it is very difficult to determine the molten metal flow rate. This research paper presents a new method of recording the molten metal height with time using a conducting metal height detector. The metal height recorded in real time during atomization was used to characterize using a model the friction losses in the metal delivery system. It is found that the integrity of the metal delivery tube and the cleanliness of the melt play a key role in the maintaining a stable metal feed.IntroductionIn the gas atomization process, molten metal is normally fed to the system either continuously using a tundish or in most cases a certain amount of metal is melted in a crucible and flows into the atomizing chamber under gravity. In the first case, the metal flow rate is believed to be constant during the atomization process despite the presence of slag or dross on the molten metal surface. In the second case, the amount of molten metal is depleted with time and the rate at which the metal flow decreases with time varies from test to test in a seemingly unpredictable fashion.' Furthermore, most atomization systems are confined units and the metal level in the crucible cannot be detected by a visualization method. In industry as well as in laboratories, the metal flow rate is normally calculated on either the mass of input material or the mass of total production divided by the duration of the test. This figure is not accurate enough and obviously cannot be used as a control parameter for the gas to metal ratio as it is only determined after the completion of an atomization run. The need exists for a metal flow rate measurement and control methodology; thereby the d50 of the powder produced may be estimated and controlled in real time. Clearly, the smaller the variation of the G/M ratio during the atomization process the more uniform the powder produced and hence the size of the particles can be predicted."

Jan 1, 1994

By Renxing Li, Yongyong Gong, Yufeng Cheng, Zhenxing Yin, Xin Cao, Qijie Zhai

"The influence of electric current pulse (ECP) on the solidification structure of SUS430 ferritic stainless steel (FSS) was investigated in the current study. The technology of ECP has been widely used to improve the properties of metals with relatively low cost. The parallel electrodes were inserted into the free melt surface to constitute a current loop. The different influences of three parameters on solidification structure were studied by changing the peak current value, frequency and treating time respectively. The results indicated that the ECP significantly increased the number of equiaxed grains of SUS430 FSS. The as-cast structure without ECP treating was almost wholly columnar, while the number of equiaxed grains of the specimen, which was treated 3min with a peak current of 400kIA, increased to 2698 in the observed surface. To get the best refinement, an optimum range of these three parameters is required and the peak current value plays the most important role.IntroductionFor the lack of nickel resource and the pressure of environment protection, ferritic stainless steel is increasingly adopted to replace the austenite stainless steel because of its low nickel content and good mechanical properties. SUS430 steel is a typical example with excellent performance and relatively low price to replace the application of austenitic stainless steel[1-3]. This type of steel with high thermal conductivity coefficient, low expansion coefficient, good oxidation resistance, excellent stress corrosion resistance and other fantastic characteristics is often used to make components which need to have resistances for atmosphere, water, steam and oxidizing acid corrosion[4]. Since the developing of columnar grains and low toughness at high temperature, its products are easily crinkled and cracked during the subsequent rolling process[5]. The application of ferritic stainless steel is limited by these defects[6-8]."

Jan 1, 2012

By Sophia Wong

Nickel is used in a wide variety of applications from consumer goods to industrial uses. In many of these uses, nickel contributes to the environmental attributes of the product. The challenge, however, is measuring that contribution, comparing it to the environmental cost of production, and communicating the role of nickel to the customer in a way that is easy to understand. This paper presents the Nickel Institute?s approach to climate change as a global commodity industry association, and discusses where we stand with regard to some of these key questions. It also identifies issues for the nickel industry moving forward ? challenges that are likely to be common to other commodities.

May 1, 2009

By R Stefansen, T Wisdom, A Nicholson, K Rahal

The challenges of increasingly scarce water resources and the risk of dam failures has seen the mining industry turn to sustainable tailings management solutions such as dewatering and dry stacking. Filtering tailings has been seen in the past as a cost-prohibitive process for larger throughput mines. However, as larger pressure filters are developed, the economic case for filtered tailings has gained traction.Focus has largely been placed on the correct design and operation of the filters. It is critical, however, that the material handling portion of the disposal system is also properly designed and operated. Thorough testing at laboratory and pilot scale to determine the conveying properties of the filtered material needs to be conducted. This testing will insure the material handling system meets the important availability needs of the mine even during periods of variability in the upstream processes and mine plan.The control system must also be robust and flexible in design to compensate for this upstream process variability. The control system needs to allow for different flowsheets including straight filtered tails as well as EcoTails™, a low-energy solution for co-mingling waste rock and filter cake.This paper will present case studies of different material handling solutions, the testing required for them and the lessons learned from each.CITATION:Rahal, K, Nicholson, A, Stefansen, R and Wisdom, T, 2018. Material handling testing and control system requirements for dry stack tailings, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 361–368 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By M. Ruonala

The Larox Power PF Pressure Filter has been developed to meet the challenges of ever increasing output tonnages demanded by the minerals processing industry. This paper will highlight recent experiences at the Rudna Copper Concentrator in Poland, the Escondida Copper Concentrator in Chile and some large zinc concentrators in Australia. Detailed maintenance and operating cost information will be disclosed. Emphasis will be placed on economics on scale gained from higher machine throughputs.

Jan 1, 1998

By L Sandery, S Light

Within 22 months of commencing decline development, the Prominent Hill Ankata Underground Project achieved its full production rate of 1.2 Mt/a.In 2010 construction of the Ankata Underground Project was approved. Decline development commenced in November 2010 and the turnout for the first sublevel was reached by August 2011. The first stoping ore was produced in the first quarter of 2012 and production was successfully ramped up to full production during the third quarter of 2012.Diamond drilling commenced in October 2011 and was conducted concurrently with the underground development. This presented challenges as mining and production targets had to be balanced with underground exploration activities. To achieve production on schedule, without adversely affecting the diamond drilling program and future development, meticulous and adaptive planning techniques were required. This included involvement from engineers, geologists, underground operators and underground diamond drillers.The granularity of these planning techniques allowed the management and prioritisation of development and diamond drilling down to an almost hourly basis. A constant flow of information from drill assay results was fed back into the planning systems. This resulted in a constantly evolving mine plan as the orebody was further refined. High priority areas were identified and targeted to allow continued development and a successful rapid ramp up to full production.CITATION:Sandery, L and Light, S, 2014. Managing the diamond drilling interactions in commissioning the Ankata underground mine, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 75–80 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By A. L. Engel

A representative sample of gold-silver ore from the Keystone Mine, Manhattan, Nye County, Nev., was submitted for these tests. The ore was an altered diorite rock with very small amounts of sulfide minerals of copper, lead, zinc, antimony, and arsenic disseminated in fine grains throughout. As indicated by test results, much of the silver content of the ore apparently was associated with these sulfide minerals. The gold probably occurred with iron oxides in the ore. Assays showed 0.16 ounce of gold and 2.8 ounces of silver per ton of ore. This investigation was made to study application of activated carbon in the cyanidation treatment of the ore. The treatment proposed for u.se at the mill is as follows: The ore is crushed to minus-10-mesh size and separated into plus -and minus-65-mesh portions. The minus-10, plus 65-mesh sands are cyanided by leaching and the minus -65-mesh slimes by agitating. After 48 hours of agitation the slime pulp is thickened to about 1:1 water:solid ratio, and part of the pregnant solution is recovered. The pulp is then diluted to a 2:1 ratio, and the remaining dissolved values are extracted with the activated carbon. The barren pulp then can be discarded. This procedure eliminates the necessity for further washing the slime pulp and also recovers most of the excess sodium cyanide required for extracting the optimum amount of silver from this portion of the ore.

Jan 1, 1951

By R. Cooper, K. De Wet, A. Janwong

"Horsehead Metal Products is a zinc refinery in Mooresboro, NC, treating crude Waelz oxide (WOX) to produce special high-grade zinc by a hydrometallurgical process comprising leaching, zinc solvent extraction/electrowinning, melting and casting and bleed treatment. Cadmium removal by zinc-dust cementation plays an essential role in the bleed treatment circuit to prevent cadmium buildup in the circuit. Silica, though present at a low level of approximately 0.3 percent in the WOX feed material, had a significant impact on the efficiency of cadmium cementation with zinc dust, most likely due to the passivation of zinc dust particles with silica gel. Solid/liquid separation efficiency by filter press was also affected. To identify the source of the silica issues, silica levels were mapped throughout the circuit, and adjustments, including using pregnant leach solution as the feed to cementation, and pH control in the WOX leaching and neutralization were introduced to mitigate the issues created by silica gel in the circuit. IntroductionLocated in Mooresboro, NC, Horsehead Metal Products Inc. is a hydrometallurgical zinc refinery processing Waelz oxide (WOX) to produce special high-grade (SHG) zinc. The flowsheet, known as the Modified Zincex process, consists of leaching, solvent extraction (SX), electrowinning (EW), melting and casting and bleed treatment (Fig. 1). Cadmium cementation, part of the bleed treatment process, provides an essential bleed of cadmium from the circuit, as metallic cement. The cadmium cementation circuit consists of agitated cementation reactors, a zinc dust addition system, filter presses, agitated purification (releach) reactors and a cadmium concentrate filter press.At the refinery, WOX pulp is leached at a controlled pH to achieve the maximum zinc extraction, according to the main reaction:"

Jan 1, 2016

By S Munn

Today, it can be said that the majority of mines utilise communications equipment in one form or another. Either for communications between staff making their day-to-day operations more efficient, or for emergency communications, as well as linking computer based mine management systems, and providing remote control over complex mobile and fixed machinery. With the advances in technology now available, we are moving into the next generation of mine communications equipment, using digital communications in the underground mine environment. It is a proven fact that an efficient underground mine communications system can help maximise production, by providing major gains in areas such as equipment and manpower utilisation, staff and vehicle tracking, reaction times to break downs and emergencies. In this paper we will describe some of the facilities that are currently available, as well as what will soon be available to mining and tunnelling companies around the world.

Jan 1, 1999

By Z. G. Song

As a kind of complex physicochemical process, grinding would affect the subsequent mineral processing such as flotation considerably. In this study, the effect of wet grinding on malachite and calcite flotation using sodium oleate as collector was studied. And the mechanism of the effect of grinding was investigated. Laboratory scale grinding and flotation testing of malachite and calcite samples were performed. Different grinding media were used, including steel balls and zirconia balls. It was the aim of this work to study the effect of grinding on the pulp chemistry paying particular attention to flotation recovery. The effect of grinding media and different addition location of sodium oleate on malachite and calcite flotation was studied. The methodology used in this project involved grinding the ore with and without the addition of sodium oleate in mill, measuring the pH and metal ions produced by minerals after grinding, adding various quantities of sodium oleate and determining the copper recovery. The presence of species of products on the minerals after grinding was probed using X-ray photoelectron spectroscopy (XPS), and the metal ions produced by minerals after grinding were measured by atomic absorption spectrometry (AAS). It is showed that the mil-ling environments evaluated significantly affected the flotation of malachite and calcite. This study also discusses the effecting mechanism of grinding environment on floatability of malachite and calcite.

Jan 1, 2014

By T Y. Dube

In this paper current net present value (NPV) based mine valuation techniques that take into account market and private risk are discussed and analysed. Potential pitfalls that arise from the application of a portfolio, market or commodity based risk metric to a mining project are identified. An alternative non-simulative framework for quantifying and factoring market and private risk in NPV calculations is proposed and then applied to a hypothetical case study in an attempt to overcome identified pitfalls. Mathematical proof that a static discounted cash flow (DCF) calculation can underestimate or overestimate mine NPV is presented, the conditions for each are outlined and the degree of underestimation defined.CITATION:Dube, T Y, 2012. How the use of market-based risk metrics can undervalue good mining projects and overvalue poor ones, in Proceedings Project Evaluation 2012 , pp 29-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

By J. -M. Lopez-Cuesta, C. Petter, B. Otazaghine, M. Batistella, R. Sonnier

"Kaolinite is a dioctahedral aluminosilicate widely used as paper filler and coating pigment. At the best of our knowledge, kaolinite is not widely used in polymer industry. Therefore, in this study, the flame retardant effect of kaolinite in ethylene vinyl acetate copolymer (EVA) and polypropylene (PP) were studied and compared with an alumina trihydrate (ATH) and Talc. Cone calorimeter results shows that the weight percentage of ATH in EVA/ATH composites must be at least 50 wt. % in order to reach an improvement in fire retardancy in terms of pHRR. In the case of EVA/kaolinite, even with 35 wt. % the pHRR is largely reduced. Comparing PP/Talc and PP/kaolinite composites at 30 wt. %, both fillers leads to same reduction in pHRR with a slightly better performance for PP/kaolinite composites. In both cases an intumescent behavior of kaolinite composites was observed that could slow the rate of the rising degradation products, allowing radical recombination reactions. Also, it was observed that kaolinite forms a protective layer on the surface of the samples, which could insulate the material. These behaviors (intumescence and formation of a protective barrier) could reduce the transfer of the degradation products to the flame and explain the better performance of kaolinite composites. INTRODUCTION The use of mineral fillers as fire retardants in polymer matrix are well known and widely studied [1]–[10]. Aluminum and magnesium hydroxides (respectively ATH and MDH) are the most widely used inorganic fire retardants. To achieve fire retardancy with these mineral fillers, about 50-60% loading is required which decrease the physical properties of the composites. The fire behavior of composite EVA has been the subject of many studies [4], [7], [9]–[15]. EVA copolymers are commonly used in the cable industry, due to their high ductility, even at high loading rates. In such applications, the flame retardant systems should be introduced into the polymer to improve the fire reaction. Many flame retardant systems have been tested but the most used industrially relates to formulations based on hydrated mineral fillers (aluminum hydroxide and magnesium hydroxide). Their low cost and reduced fumes generation explains their success. However, to obtain good performance with this type of flame retardants, it is necessary to incorporate high levels (up to 65 wt %), which severely impact other properties such as processability and mechanical behavior. The main modes of action of these flame retardants are the dilution of the gas phase, the endothermic decomposition and a barrier effect created by the inorganic oxide residue which may be improved by the incorporation of other components such as montmorillonites, silicas or talcs."

Jan 1, 2015

It is well known that the crushing and grinding steps in the mineral processing of ores represent a substantial proportion of total energy, cost and carbon emission in mining. For instance a recent study calculated that 36% of the energy consumed by gold and copper producing mines in Australia was attributable to comminution (Ballantyne et al, 2012). Understanding this component of a business is essential in a world seeking to lower production costs, improve earnings and reduce its carbon footprint. The issue commands the attention and support of industry leaders in the mining sector, government, equipment manufacture, engineering design and research organizations. Furthermore, several researchers have often stated that globally, comminution processes consume between 3-4% of the world?s electrical energy production (Daniel and Lewis-Gray, 2011). In 2009-10, Australia?s Federal Government Energy Efficiency Opportunity (EEO) participants in the mining sector used 336.5 PJ, representing approximately 6 percent of Australia's total energy use. It is evident that the current practices of breaking rocks in tumbling mills are relatively inefficient (Fuerstenau and Abouzeid, 2002). Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower project costs and carbon footprint. These include relatively simple process flow sheet strategies such as gangue rejection or pre-concentration prior to size reduction, a better combination of grinding technologies (both current and new systems), and selection of coarser grind sizes where ore and waste mineralogy allow. Yet, despite this systematic and detailed research, the industry remains somewhat reluctant to implement these strategies. CEEC (Coalition for Eco-Efficient Comminution) was established in 2011 to support knowledge sharing and change in an area of high-energy consumption for the global mineral industry. CEEC is a not-for-profit industry company, funded by grants from world wide industry companies, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution. The key benefit to the mining sector arising from CEEC?s activities will be an increase in the rate at which more energy-efficient comminution data sets, processes, and technologies are developed, demonstrated, shared and applied. This will contribute directly to the industry?s target of reducing operating costs and carbon emissions. CEEC International Ltd and JKTech Pty Ltd teamed together to facilitate the inaugural CEEC Workshop, in June 2012. The purpose of the workshop was to produce a roadmap to provide guidelines for how (1) operations can achieve best EEC practice in the short to medium term, in collaboration with vendors, engineering companies and other service providers, and (2) what R&D is needed to achieve paradigm change in EEC in the medium to long term, e.g. 75% reduction in comminution energy in 10 years.

Sep 1, 2012

By H. A. Kramer

The Flin Flon mine is at present hoisting 5,000 tons of ore daily. In 1943, a peak production of 6,188 tons daily was maintained. Before discussing secondary blasting, it is felt that a short review of stoping procedure will be of value. A list of papers dealing with various phases of the mining operation is appended. Stoping Practice Stopes vary in width from 30 to 150 feet, in length from 200 to 450 feet, and in height from 200 to 500 feet. A typical stope would be 300 feet long, 300 feet high, and 90 feet wide. The dip of the orebodies varies from 60° to vertical, with an average of 82°. The ore is heavy, having a specific gravity of 4. Both sub-level benching and radial drilling are practised. Blast-hole diamond drills are responsible for 85 per cent of the total production. Two sizes of hole are drilled at present, 11 7 6 -inch and 1%-inch. For bench drilling, the burden on the 1 7/16-inch hole is six feet, with holes on 8-foot staggered centres; in radial drilling, the burden is six feet, with nine feet between the toes. The burden on the l 5/8-inch hole is eight feet with holes on 11-foot centres, or 13 feet on the toe of fanned holes. Holes are blasted with two No. 8 instantaneous electric caps per hole, using 403 Polar Forcite. A powder charge of 0.15 pounds per ton is used, with a tonnage factor of 5 and 6.4 per foot drilled for the two sizes. Two rows of holes are blasted together. Fragmentation is satisfactory with the above drilling pattern and powder charge. However, some overbreak and fall-off locally results in oversize material. It is estimated that, after primary breaking, 75 per cent of the ore will pass through the grizzly openings and 15 per cent will pass the draw points, leaving 10 per cent that must be broken further to pass the draw points.

Jan 1, 1946

By L. Alagha, M. Khodakarami

"This work focuses on the extraction of rare earth metals (REE) from aqueous solutions using stimuli-responsive polymers. Various parameters affecting the adsorption capacity of the polymer, including pH, polymer concentration and REE concentration were studied. The interfacial behavior of REE in aqueous phase before and after polymer addition and the mechanism of the formation of metal-polymer complexes and their properties were investigated using UV/VIS spectroscopy. Results obtained would help to test the feasibility of employing stimuli responsive polymers in pre-concentration of rare earth elements associated with other elements in mineral aqueous streams prior to solvent extraction. The pre-concentration step would reduce the amount of organic solvents used for extraction and striping compared to conventional extraction processes. INTRODUCTION Rare earth elements (REEs) have become the foundation for several technologies and have been used extensively in many industries such as modern electronics, green energy, health care and transportation and defense [1-4]. As these industry sectors are growing, the global consumption of REEs is going to increase dramatically. The current global REEs demand is estimated to be 105,000 tons of rare earth oxides per annum with an expected annual growth of 5.6% [5-6]. Rare earth elements are produced from different sources (primary and secondary). China is considered as the largest producer of REE in the world, providing about 90% of the world’s mine production while the United States is second with 4% of the mine production [7]. High global demand for rare earth materials results in shortage of such materials in the near future. It should be considered that the term ‘‘rare’’ earth is not an accurate term, since they are abundant in some extent in the Earth’s crust, but are typically finely dispersed. Thus, nowadays looking for more efficient and cheaper methods for extraction, separation and purification of low concentrated REE ores and exploring secondary sources are essential. Rare earth materials are found in raw condition and require treatment that involves several processes, which can consume money and time. Recent improvements in extraction and recycling technology have made the extraction of rare earth elements from rare earth sources more feasible in terms of cost and time [8-10]. Physical and pyrometallurgical methods require high-energy and thus high costs. Moreover, due to environmental problems, environmental protection systems are required, and they are not as adaptable as chemical processes [11, 12]."

Jan 1, 2016

By S. Duvah Pentiah

The transformation of an open pit coal mine to a horizontal-punch underground mine is subject to a number of challenges. These include scheduling the operation of various sizes of trucks over a long period, as well as updating delivery routes and dump site locations as the mine transformation progresses. In this process, rock is excavated from a quarry through earthworks. The bulk earthwork and quarry material delivery were initially drawn from traditional planning and experienced issues in their early phases. As a result, a traffic simulator was developed in order to validate schedules and predict achievable throughput, likely delays or blockages in the long term. The dynamic traffic simulator was also used to provide traffic density and vehicle arrival data at selected intersections in order to identify possible safety and efficiency issues.

Aug 1, 2013

By Mark Khinkis, Huajun Yuan, Mark Zak, Yaroslav Chudnovsky, Aleksandr Kozlov

"An afterburner for green petroleum coke calcination in electrothermal fluidized bed was designed, fabricated, installed, and tested on a pilot fluidized bed calcination furnace. The experimental set-up comprised a combustion chamber, in which fine particles and volatiles of the furnace off-gas were fully combusted, and a cooler equipped to calculate the related heat recovery and losses. Off-gas composition was analyzed to evaluate the combustion process. The energy balance confirmed the potential to recover a large part of the heat value of volatiles and fme particles from the GPC. Potential future applications of the results are discussed.IntroductionGreen petroleum coke (GPC) is an oil refining byproduct that can be used directly as solid fuel or as feedstock for the production of calcined petroleum coke [1-2]. GPC contains a high amount of volatiles and sulfur. With coke calcination, the GPC is heated to remove the volatiles and sulfur in the calciner off-gas to produce purified calcined coke, which is used in the production of graphite, electrodes, metal carburizers, and other carbon products. Currently, more than 80% of calcined coke is produced in rotary kilns or rotary hearth furnaces. These technologies provide partial heat utilization of the calcined coke to increase efficiency of the calcination process, but they also share some operating disadvantages [3]. On the other hand, coke calcination in an electrothermal fluidized bed opens up a number of potential benefits for the production enhancement while reducing the capital and operating costs.The increased usage of heavy crude oil in recent years has resulted higher sulfur content in green coke produced from oil refinery process, which requires a significant increase in the calcinations temperature and residence time [ 4]. The calorific value of the process off-gas is quite substantial and can be effectively utilized for combined heat and power (CHP) production to complement the energy demand. Waste heat recovered from the product cooling could also contribute to the overall economics of the calcination process. Preliminary estimates indicated the decrease in energy consumption by 35-50% as well as a proportional decrease in greenhouse gas emissions. So, efficiency improvement of the coke calcinations systems is attracting close attention of the researchers and engineers throughout the world."

Jan 1, 2014

By W. L. Ott, C. L. Lewis

"AbstractA technique is described for preparation of palladium sponge and for spectrochemical analysis of the metal in this form. The precision and accuracy of the method are discussed. Analyses are compared with previous spectrochemical analyses of palladium in the black form. Good agreement was found in the two sets •of results and it is concluded that they are more reliable than wet chemical .analyses of the same material.IntroductionFOR SEVERAL YEARS the problem of platinum metal analysis by spectrochemical methods has been under investigation at the Spedtrographic Laboratory, Department of Geological Sciences, Queen's University. The problem, briefly -stated, is as follows: Samples of platinum, palladium,-rhodium, ruthenium, and iridium are received as fine metal powders, called sponge. Direct spectrographic analysis of this material has not been found satisfactory due to its heterogeneity •as regards contaminant metals, which may be present up to a total of one per •cent or more. Further-more, spectrographic standards are difficult to obtain and difficult to prepare accurately by adding weighed portions of contaminant metals to the sponge. The fact that •contaminant metals in original samples are probably alloyed with the major constituent is a further difficulty since complete fusion of these refractory metals proved impractical in the present case as a means of standard preparation. It •has, therefore, been found most satisfactory to dissolve the metals, prepare standards by addition of solutions of contaminant metals, and to reduce both standards and samples to a homogeneous form. A previous paper, by Hawley, Wark, Lewis and Ott (2) dealt with a method for spectrochemical analysis of platinum and palladium in their black form. Since completion of research on the black technique, the possibility of analyzing palladium accurately in its sponge form has• been investigated."

Jan 1, 1953