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By D. R. Boyle

"The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite _ arsenopyrite _ galena _ Bi-Sb sulfosalts _ chalcopyrite _ tetrahedrite group _ sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was transported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By D. R. Boyle

"Abstract - The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite > arsenopyrite > galena > Bi-Sb sulfosalts > chalcopyrite > tetrahedrite group > sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was trans- ported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By C. G. McLachlan

Abstract This paper deals with the application of the cyanide process to recover gold from a pyrite concentrate produced by means of differential flotation. This concentrate before cyanidation contains from 0.09 oz. to 0.14 oz. gold per ton, of which only about 60 per cent is recoverable. The rest is so fine that it remains interlocked in the pyrite and therefore is not acted on by the cyanide. The concentrate also contains about 15 per cent pyrrhotite and 0.4 per cent chalcopyrite, both of which are cyanicides. The cyanicidal effect of the pyrrhotite is inhibited by preacracing the pulp with lime, and maintaining a high lime alkalinity during cyanidation. The effect of the chalcopyrice is reduced as far as possible by removing those particles which are free by means of a further flotation step immediately prior to cyanidation. This involves the flotation of some very fine material. After nullifying as far as possible these two cyanicides, the concentrate is cyanided directly, i.e., without being roasted. This leaves the pyrite available for subsequent sale as a source of sulphur dioxide and sulphuric acid, and the entire residue of the cyamde plant, amounting to about 500 tons per day, 1s now being disposed of in this way. Prior to deciding on direct cyanidation, a number of laboratory roasting tests were made. These showed chat, 1f proper control were exercised, a better recovery of gold could be effected from the roasted product than by the direct method of treatment. The tests also showed that the capital cost o the plant would be much higher than that needed for the procedure adopted. The possibility of subsequently selling the pyrite for its sulphur content would also have been eliminated. Introduction A previous paper has described in considerable detail the application of the flotation process to improve gold recovery from Noranda's milling ore, and in so doing has covered the production of an auriferous pyrite concentrate. The present paper deals with the recovery of gold by cyanidation from that concentrate. This gold, though intimately associated with the pyrite, can, for metallurgical purposes, be considered as all occuring in the native state.

Jan 1, 1946

By M. H. Pettibone

Sohio Petroleum Company's new L-Bar uranium mill near Grants, New Mexico. refines 2722 kilograms of yellowcake daily from 1360 metric tons of ore produced at Sohio 's J.J. No. 1 mine and other nearby mines. This paper follows the ore from the mine through the various processing steps - semi-autogenous grinding, acid leaching , countercurrent decantation, solvent extraction , ammonium diuranate precipitation, washing and drying, and tailings disposal.

Jan 1, 1978

By Tong Guan, Guangqin Fu, Lihong Deng, Yuanlin Chen, Xiaotong Zhou

"In natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the content of MoO3 varies from 2% to 10%. As a result, the flotability of seyrigite (scheelite with molybdenum) turns to be weaker. One seyrigite mine, which has been built for 3 years,still could not produce qualified seyrigite concentrate due to the weak flotability of seyrigite (Mo-bearing scheelite) in raw ore. In our experimental research, through adopting new seyrigite collector TA-3 and advanced mineral processing technology, the seyrigite concentrate with a grade of 65.62% WO3 at a recovery of 87.47% was obtained for the raw ore containing 0.19% WO3 and 0.074% Mo. By applying the new technical achievement, for the raw ore containing 0.272% WO3, the seyrigite concentrate assaying 68.03% WO3 with a recovery of 77.56% was obtained in industrial production.INTRODUCTIONIn natural world, some kinds of scheelite minerals are rich in molybdenum. Molybdenum exists in the crystal lattice of scheelite in the form of isomorphism, and the scheelite is changed to be seyrigite (Ca[(W,Mo)O4]) (Ma, Bian, & Wang, 2013). The content of MoO3 in seyrigite varies from 2% to 10% usually, the content of MoO3 in some of the seyrigite even reaches 34%. The flotability of seyrigite is weak (Zhang, 2007), and the seyrigite is difficult to be recovered by flotation with common collectors and regulators. One scheelite mine in Anhui China, which is a skarn type seyrigite mine, has not produced qualified concentrate yet since 3 years it has been built due to the limit of beneficiation technology. Therefore, it is necessary to conduct research on the collectors with high efficiency and developing advanced processing flow for this kind of ore."

Jan 1, 2016

By G. Merle, David L. McKay, Elmar Randveer

"THE ENGINEERING AND TECHNICAL SERVICES department is responsible for supplying the following services:1. Administration and co-ordination of the work required for capital projects.2. Engineering, design and drafting services for inplant changes or improvements as requested by the operating• and maintenance departments.3. Rock mechanics.4. Preparation of plans and layouts required for efficient extraction of the ore as mutually agreed with the mine operating departments.5. Mine planning and long-term schedules in co-operation with the mine operating departments.6. Grade control (long term and short term) and the preparation of ore and waste removal schedules to maintain a uniform grade of mill feed. This also includes the calculation of metal reserves and metal production forecasts.7. Surveying, underground and surface.8. Operations research at the mine site.9. Industrial engineering.10. Chemical analyses and assays.11. Instrumentation.12. Environmental control.A staff of approximately 35 supervisors, engineers and scientists, and 80 technicians, supply the foregoing services. Consulting engineering and drafting firms are used to supply specialized services and technical personnel in-house at Timmins to handle overloads on capital projects under the direction of Ecstall engineers.The operating and maintenance departments depend on the engineering department to supply engineering, design and drafting services for any new facilities or for any planned alteration to existing facilities. To do this efficiently requires a high level of communication and co-operation with these departments. This has been a major factor in developing the present organization of the department shown in Figure 63.The organization is predicated on a strong central technical and engineering resource from which personnel can be assigned responsibilities for different projects, and in different areas, as the work load demands. Job satisfaction is very high because of the variety and challenge in the tasks. Additionally, participation in projects with production and maintenance personnel broadens each technical employee's knowledge of operating and maintenance problems."

Jan 1, 1974

By A. Quilodran, B. Jakovljevic, T. McCallum, P. Wong

"Rare earth separation by solvent extraction (SX) requires multiple separation plants each consisting of many extract, scrub, and strip stages to separate the individual metals. SX modeling advances have brought benefits to circuit design and process optimization by quickly narrowing test conditions without the need for exhaustive laboratory studies. Modeling can be used to optimize circuit configuration, O/A ratios, and acidities, which allows for CAPEX and OPEX savings. A comparison between pilot plant data and the results expected from modeling is presented for rare earth separations with CYANEX® 572.INTRODUCTIONRare earth separations can be difficult due to limited separation between the elements (Xie, Zhang, Dreisinger, & Doyle, 2014). This requires relatively complex solvent extraction circuits utilizing multiple extract, scrub, and strip stages as well as multiple SX configurations to achieve the desired metal purities. Designing rare earth circuits can be complex, and significant time and testing may be necessary to determine the required staging and optimal conditions.Circuit modeling for rare earth separations has been introduced to the industry using CYANEX® 572 extractant (Soderstrom, McCallum, Jakovljevic, & Quilodran, 2014). CYANEX® 572 is an acidic organophosphorus extractant formulation which has a weaker ligand-metal complex strength than that of the traditionally used phosphonic acid extractants. This allows efficient extraction while requiring a significantly lower acid concentration for stripping (Wang, Li, Zhao, Dong, & Sun, 2015). The reduced acid requirement in strip is expected to provide OPEX savings.The modeling can be utilized to quickly determine the required acidity and organic/aqueous (O/A) ratio for a given separation. It is also expected to reduce CAPEX requirements as optimal staging can be determined, and implemented.CYANEX® 572, combined with modeling, was utilized to produce a purified dysprosium (Dy) stream. To achieve this separation, multiple SX circuits were designed and operational conditions specified to separate Dy from the mixed rare earth chloride feed."

Jan 1, 2016

The topic of the relationships between energy and particle size has had two very active periods -the first in the early thirties, when the relative merits of Rittinger's and Kick's proposals were vigorously debated; the second in the early fifties, when Bond's Third Theory was published. This second stage has produced several contributions that have provided a clearer picture of energy /size correlations in comminution. Derivations of a general relationship have been made from single-fracture experiments and from the rate of comminution, and both methods arrive at an equation of the type E = AK-11? The constant A in the equation may be regarded as a grindability parameter. In some respects, an understanding of the phenomena associated with comminution is still lacking, and research in this field should therefore be expanded. T HE SEARCH for a relationship between the energy consumed in comminution and the size of the broken product has been long and varied, and many

Jan 1, 1964

By T. Hofbauer, M. J. Dry, G. B. Harris, C. W. White

"Urban Mining is a term that is increasingly being used, and represents an appreciable source of secondary materials for the metals extraction industry, a source that does not incur mining costs, but does, at present, incur considerable disposal costs. Electric Arc Furnace Dust (EAFD) is probably the most common of these materials, with an estimated global production of 8 million tonnes annually, of which 1 million tonnes is generated in North America. The contained annual metal value in EAFD at current prices is of the order of $6 billion, yet, apart from the zinc, virtually none of this is recovered.Despite many attempts over the years, with pyrometallurgical, hydrometallurgical or hybrid processes, currently the only commercially viable method of treating these materials is smelting in a Waelz Kiln (or a Rotary Hearth Furnace), which essentially recovers only the zinc, in an impure oxide form, and generates a secondary slag waste, which is still toxic and requires disposal. This paper describes the development of a chloride-based treatment process to recover all components of the EAFD in a marketable form, which centres around the novel hydrochloric acid recovery and recycle operation. Laboratory, miniplant and pilot plant data are presented, leading to the definition of a viable process flowsheet enabling the recovery of pure iron and zinc products (the principal components of EAFD), together with secondary products such as copper, silver, lead, cadmium, magnesium and manganese. A rigorous mass-energy balance is used to examine the preliminary economics involved."

Jan 1, 2014

By Zhiwei Wang, Chunsheng Qiao

"Aiming at the problems of the existing calculation methods for the support pressures of shallow tunnels in layered jointed rock strata, by using OAT (orthogonal array testing strategy) and DEM (distinct element method), 12 influencing factors including the thickness of the weathered overburden, and the states of the rock joints were considered. Then, the classification of the loosening zone was analysized. On this basis, by using the DEA (data envelopment analysis) theory, quantitative analysis on the influencing factors was conducted. By analyzing the influence of the key factors, a prediction formula of the boundary of the ringent trumpet-shaped loosening zone was established. According to principles of stress transformation, the formula of support pressures of the loosening zone which could considering the key factors were deduced. Finally, a practical case was introduced and studied to verify the proposed method.INTRODUCTIONIn recent years, various urban subway tunnels are increasingly carried out through jointed rock strata in many cities. Rock masses are discontinuous mediums with fissures, fractures, joints, bedding planes, and faults. The frequency of joints, their orientation with respect to the engineering structures, and the roughness of the joint have a significant importance from the stability point of view. However, there is a lack of understanding about the influence of the joints on the stability of tunnels. Therefore, how to measure the degree of the joints’ influence is a problem that needs to be solved.For the calculation of the support pressures, until now, many research results were focused on soil ground (Bierbäumer 1913; Terzaghi, 1943; Peck, 1969; Sabatini et al., 1999). In terms of site tests and model indoor tests, by measuring strut loads and calculating earth pressure based on strut spacing, the results proposed by Peck (1969) and Tschebotarioff (1973) have been widely used in practice for designing excavation support systems under sand (drained) and clay (undrained) soil conditions. Note that, it is unclear whether these findings could be extended to rock strata. For numerical simulations, how to simulate the states of the rock joints is a key problem that needs to be solved."

Jan 1, 2015

Access to accurate real-time information is critical to maintaining efficiency and competitiveness in any modern minerals processing facility. At MMG LXML Sepon Copper Operation in Lao P.D.R., controlling the copper grade of the feed to the leaching circuit is paramount for maximising productivity and copper recovery. Since 2008, real-time analysis data has been available to process engineers from the Geoscan on-belt analyser installed on the Copper Mill feed conveyor. Access to accurate real-time results from the Geoscan has allowed the process engineers to strictly control blending based on copper grade to overcome variability in the plant feed, where conventional sampling and laboratory analysis is difficult, error prone and time consuming. In addition to enjoying these benefits since the Geoscan’s installation, in recent times the process engineers have expanded the use of the Geoscan by observing elemental results other than copper grade to control different aspects of the operation, focussing on the reduction of Gangue Acid Consumption. This paper discusses the process of expanding the Geoscan use at the operation, including an explanation of the calibration process. Additionally, a brief description of the Geoscan and its use at MMG LXML Sepon Copper Operation is provided, as well as a summary of recent calibration and analysis results. A discussion of future works concludes the paper.

Jan 1, 2016

By E. E. Mason

THE Myrtle group of mining claims is situated on Barkerville mountain in the Cariboo mining district of British Columbia, west of the old mining town of Barkerville. An 1,800-foot adit, known as the Shamrock tunnel, was driven in 1935-36 from the Barkerville road and in the general direction of the Myrtle group. It was proposed to enlarge this adit to more convenient section, extend it 2,500 feet int0 Myrtle ground, and from there drive a main entry 3,000 feet along the length of the group. Several laterals were also to be driven off this main entry as part of the tunnel schedule. It was thus originally proposed to drive 5,500 feet of new adit and 1,800 feet of laterals, a total of 7,300 feet of new work. Work was commenced with a bulldozer on April 21st, 1941, cutting a bench on the hillside for a plant site. The power plant was ready for operation on August 8th. Slashing and re-timbering of the old adit rook longer than was expected. It was found that 57 per cent of the length required timbering, chiefly by fore-poling, and there was also trouble in several sections with swelling ground. First round in the new face was taken on September 17th, when a 2-shift daily schedule was commenced. Due to delays in delivery of electrical equipment, it was not possible to add the third shift until November 14th. From then on, a 3-shift daily schedule was maintained with the exception of holidays and fortnightly change Sundays until August 1st, 1942, when shortage of labour caused the dropping of a shift. All work was suspended on August 14th. The ground through which the tunnel passed was such that the driving was often interrupted by the need of protective timber at the face. Further, crews were continuously employed timbering behind the face, and in maintenance of timbered sections in swelling ground. Roughly 980 feet of the new workings are now timbered, about 21 per cent of the total.

Jan 1, 1942

By F. McGravie, S. T. Solinski, W. W. Robertson

During this, the Centennial year of the discovery of the Hall-Heroult process, it seems appropriate to review some of the developments which have taken place in Canada and to explain why it has become an important world centre for the production of primary aluminum. For many years after it was recognized that the element aluminum existed, scientists were frustrated in their efforts to isolate it. In the early 1800s H. C. Oersted and Frederick Woehler prepared small quantities sufficient to measure some of the physical properties. A quasi-commercial process involving reduction with metallic sodium was developed by the French scientist H. St. Claire Deville in 1855 but the cost was very high ($30. 00 per kg). It was not until 1886 that Charles Martin Hall in the United States and P.L.T. Heroult in France, more or less simultaneously but completely independently, discovered the process which is essentially that in use today. Some of the early pioneers in the industry quickly recognized the potential of the hydro-electric resources in Canada as economic energy suppliers for aluminum production. The first commercial production in Canada was in Shawinigan, Quebec in 1901, only 15 years after the process was discovered. Subsequently operating plants were established at nine different locations in Canada (Quebec and British Columbia) (Table 1). Operations continue today in all locations except one (La Tuque). The table shows present plant capacity which for the older plants was reached in an evolutionary manner including replacement of obsolete capacity or upgrading and modernization of existing designs.

Jan 1, 1999

By P. L. Li, B. X. Song, C. H. Wang, T. Wang, Z. Hu

"The treatment of an oxidized copper-gold ore by stage cyanide addition was investigated. For cyanidation, free cyanide ion concentration can be an indicator of whether there is copper dissolved in cyanide solution, and maintaining the free cyanide ion concentration lower than 1.0 g/L could be an effective way to prevent copper dissolution and reduce cyanide consumption. For that purpose, stage cyanide addition was introduced to control free cyanide ion concentration within the range from 0.8 to 1.0 g/L. Cyanidation tests results indicate that gold extraction was still acceptable at reduced cyanide consumption with a lower copper extraction. Based on the experimental study, industry application works at Beiya concentrator of Yunnan province, China were successfully conducted. When the raw ore contains 2.95 ppm Au and 0.75% Cu, by stage cyanide addition method, the gold extraction was still 93% at reduced cyanide consumption of 2135 g/t, which was only half of one addition method, and the copper extraction dropped to only 5%, which indicated that dissolution was prevented for almost 75% of the malachites.INTRODUCTIONCyanide with its competency to form a strong complex with gold, is the most preferable lixiviant for gold leaching. However, cyanidation is not inherently a selective process since many other minerals present in the ore are also readily soluble, especially the copper minerals. Muir (2011) reported that every 1% reactive copper present in the ore consumes about 30 kg/t NaCN, which can have detrimental effects on the process efficiency and economics due to high cyanide consumption, reduced gold leach rates and poor gold recovery."

Jan 1, 2016

By R. D. Brown

"Finance Minister Donald Macdonald's budget of May 25, 1976 featured a restructuring of the anti-inflation profit controls and a grab bag of tax changes, some of direct interest to the mining industry. All Canadian taxpayers now will be permitted to write off immediately 100% of mineral and oil and gas exploration expenses included after• May 25, 1976 and before July 1 1979. The cost of acquitting Canadian resource property after May 6, 197.4 from a federal or provincial government will now clearly be included in Canadian development expense, and provincial drilling and exploration incentives received after May 25, 1976 will not reduce exploration and development expense for federal income tax purposes. Under tough new anti-inflation profit controls, all controlled businesses, except distributions, will essentially have one uniform set of rules for• determining allowable profit margins; this allowable margin will be determined by product line or by over-all net margin and will be 85% of the higher of the margin obtained in the five years preceding October• 13, 1975 or the one year preceding May 1, 1976. The basic capital cost allowance system is to continue, but many rates will be revised. The ability to offset losses created through claiming capital cost allowances on leased equipment, etc. against other income will be ended with respect to transactions entered into a/te1• budget night. Miscellaneous other tax changes will raise the low rate base for Canadian-controlled private corporations to $750,000 increase retitement plan contribution limits and reduce the rate of branch tax imposed on branches of corporations resident in a country with which Canada has a comprehensive tax treaty to equal the withholding tax rate on dividends under that treaty."

Jan 1, 1976

By T. H. Etsell, P. Kerr, Qi Liu

"The objective of this investigation was to study the reaction mechanisms during the reduction of iron oxides in the presence of calcium chloride and carbon black as a simplified iron segregation process. The gas phase was analyzed by mass spectroscopy and the solid reaction products were analyzed by scanning electron microscopy. Mass spectroscopy, combined with thermogravimetric analysis and differential scanning calorimetry, revealed the presence of several gases at elevated temperatures over time, and the scanning electron microscope in combination with energy dispersive X-ray analysis illustrated the growth of a metallic iron phase on or near the carbon substrate. The results correlated well with similar copper and nickel segregation processes, but also introduced new insights that challenge the simplicity of the current models. The formation and transport of gaseous iron species to the carbon substrate in the presence of steam and hydrogen were evident during the reduction process that was studied; however, there is more happening at a mineralogical level, based on evidence of a liquid phase resulting in substantial growth due to an apparent fluxing effect created by the calcium chloride.These results help to better explain the chemical reactions and, in turn, the thermodynamics and kinetics of iron segregation processes related to the beneficiation of low grade complex iron ores. The results are also applicable to the production of metallic iron and concentrated titanium dioxide from ilmenite ores. The benefit of this process is that it allows ores in which the iron minerals are intimately associated with gangue minerals to be processed in circumstances where conventional mineral processing techniques are unsuitable or incapable of upgrading the material."

Jan 1, 2016

By H. Z. Liu, J. M. Zhao, F. C. Wang

"Novel silicate-alginate composite beads containing 2-ethylhexyl phosphonic acid mono-2- ethylhexyl ester (P507) were synthesized and applied for the adsorption of Nd3+ from aqueous solutions. The adsorption amount of Nd3+ has been increased owing to the introduction of P507. The effect of equilibrium pH (pHe), the kinetic and isotherm experiments were investigated. The adsorption reaches equilibrium at 9 h and the maximum uptake capacity is up to 195.4 mg/(g dry adsorbent). The Langmuir isotherm equations are used to describe the adsorption process. Complete desorption can be realized with 0.2 M HCl within 20 min. INTRODUCTIONRare earth elements (REEs) have found various applications in different domains, such as metallurgy industry, ceramic industry, nuclear fuel control, photo-electro-magnetic functional materials owing to their unique properties. Neodymium (Nd), as a representative of all of the most valuable REEs, is widely used as catalysts, laser crystals, capacitors, rubber additives, Nd-Fe-B magnets, hydrogen storage and so on. Thus, the separation and purification of neodymium is significant. Unfortunately, Nd always coexists with other REEs and selective separation of the individual Nd from the REEs mixtures is still extremely difficult owing to their strictly similar atomic structures and chemical properties.Liquid-liquid extraction (LLE) and solid-liquid adsorption (SLA) are the most widely adopted techniques for the separation of REEs in the hydrometallurgical fields. The LLE process is well suited for large-scale continuous operation because of its inherent high capacity and fast kinetics. Nowadays, as a commercial extractant, 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) has been extensively studied for extraction and separation of REEs since it has considerably good extractability and high separation efficiency (Xu et al., 1992). SLA is one of the effective and green separation methods with some prominent advantages, such as easy regeneration of adsorbents, small footprint size, less industrial wastes, higher enrichment factors and column efficiency,rapid solid–liquid separation without emulsion and so on. Hence, the introduction of extractants with excellent performance into adsorbents will integrate the advantages of LLE and SLA (Lee et al., 2009)."

Jan 1, 2012

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By X. Q. Jiang, D. L. Chen, A. Macwan

Magnesium alloy, being the lightest structural material, is a key candidate for the weight reduction of vehicles in automotive and aerospace industries; however, its poor corrosion resistance and difficulty in deformation are limiting factors. Recently, Al/Mg/Al tri-layered clad sheets have been considered as a promising alternative to improve corrosion resistance and formability of magnesium alloys. The aim of this study was to evaluate the tensile properties and deformation behavior of Al/Mg/Al tri-layer clad sheets at different temperatures and strain rates. Yield strength (YS), ultimate tensile strength (UTS), and elongation were observed to increase with increasing strain rate. With increasing temperature from -40°C to 180°C, YS and UTS decreased and ductility increased. The strain hardening exponent evaluated via three equations of Hollomon, Swift, and Afrin et al. showed a similar increase with increasing strain rate and decreasing temperature. The fractographic analysis showed partial debonding of clad interface especially at higher strain rates and lower temperatures.

Jan 1, 2015

By Kurt F. Weitz

"The number of materials that can be classified as fillers covers an extremely wide range: this paper outlines those fillers of the industrial mineral type that find extensive application in the paint and plastics industriesIn the paint industry, mineral fillers are known as extender pigments. Extenders are added to paint and plastic compositions to (1) lower the cost and (2) rein-force or modify the physical properties of a composition.Commonly used extenders are classified according to chemical type and discussed in terms of the change in physical properties that they impart to a paint or plastic film. Available cost reductions and data on the consumption of extenders in the Canadian paint industry are also included."

Jan 1, 1970