Magnesium Silicate Minerals Research Articles

Enhancing serpentine dissolution kinetics for mineral carbon dioxide sequestration

Mineral carbon dioxide sequestration binds carbon dioxide by reacting it with magnesium silicate minerals to form solid magnesium carbonates that are ready for disposal. Research on mineral sequestration has focused on enhancing process kinetics in aqueous processing schemes. High costs of these processes are associated with mineral processing, such as ultrafine grinding, or the consumption of acids and bases, which are required to speed up silicate mineral dissolution kinetics. Neutral organic salts such as sodium oxalate, and citrate enhance dissolution kinetics of serpentine in the circum-neutral pH range appropriate for mineral carbonate precipitation and have potential for use in an enhanced carbonation process. Concentration and temperature dependencies for the dissolution of antigorite serpentine in the presence of the citrate ion are experimentally derived under weakly acidic conditions. Rates are shown to be several orders of magnitude higher in the presence of citrate than in the weakly acidic solution alone.

Integrated carbon capture and storage for an oxyfuel combustion process by using carbonation of Mg(OH)2 produced from serpentinite rock

Abstract The increasing atmospheric carbon dioxide concentration has lead to concerns about global warming. One of the options that can contribute to the reduction of carbon dioxide emissions is CO 2 sequestration by mineral carbonation. In this paper we will present a model of an oxyfuel combustion process integrated into a carbonation process using Mg(OH) 2 produced from magnesium silicate mineral. Therefore, the objective of this work is to develop integrated carbon dioxide capture and storage methods for an oxyfuel combustion process where CO 2 will be captured directly from the flue gas in a carbonation reactor. There it reacts with injected magnesium hydroxide Mg(OH) 2 solid, with thermodynamically stable MgCO 3 as the final product. In this paper we will present a process model that illustrates how the carbonation process integrated into oxyfuel combustion could be an alternative process for oxyfuel combustion followed by geological storage of CO 2 . We will also present a simulation model for this process by using Aspen Plus ® simulation software.

Enhanced CO 2-mineral sequestration by cyclic hydraulic fracturing and Si-rich fluid infiltration into serpentinites at Malentrata (Tuscany, Italy)

The magnesite deposits of Malentrata (Tuscany, Italy) were derived from serpentinite silicification–carbonation of the Ligurian ophiolite, and represent a natural analogue of in situ CO 2 mineral sequestration. Carbonation of magnesium silicate minerals (e.g. serpentine, olivine) at temperatures below 200 °C is an exothermal process, involving incorporation of carbon dioxide into stable carbonates (e.g. magnesite, dolomite). Serpentinites at Malentrata were transformed to a brownish friable rock characterized by the occurrence of opal, chromian montmorillonite, Fe-rich magnesite and minor iron sulfides and oxides. Widespread lenses of cohesive rocks occur within the altered serpentines, resulting from the complete silicification of the protolith. The pervasive alteration of serpentinite was accompanied by the formation of a network of magnesite and dolomite veinlets, and large magnesite–dolomite veins along major structures. Field observations, petrography and mineral chemistry define the following crystallization sequence in the major veins: i) early microgranular Fe-poor magnesite, ii) comb-textured Fe-rich magnesite and dolomite cementing the early brecciated magnesite vein infill, and iii) late quartz, chalcedony, and rare opal in the cavities. The mineral assemblage observed both in veins and in host rock is indicative of low-temperature hydrothermal alteration driven by Si- and CO 2-rich fluids under relatively low pH conditions. Pervasive and cyclic hydraulic fracturing maintained a high structural permeability during the whole hydrothermal event, creating conduits for the input and output fluids. The concomitant presence of CO 2 and silica in the fluid enhanced the congruent dissolution of serpentine and hampered immediate carbonate deposition. The Mg-bearing solutions were focused out of the reactor zone, and promoted massive carbonate veining along the main structural discontinuities. This two-steps reaction (dissolution of serpentinite followed by carbonate precipitation outside the reacting volume) seems to be very efficient and provide new insights on in situ and ex situ induced mineral carbonation and its industrial applications.

Suppressive effect of magnesium oxide materials on cadmium accumulation in winter wheat grain cultivated in a cadmium-contaminated paddy field under annual rice–wheat rotational cultivation

The effectiveness of two kinds of magnesium oxide (MgO) materials, commercial MgO (2250 kg ha −1) and a material derived from MgO and magnesium silicate minerals named ‘MgO-SH-A’ (2250 and 4500 kg ha −11), in suppression of uptake and accumulation of cadmium (Cd) into grain of winter wheat ( Triticum aestivum L. cv. Ayahikari) was examined in a Cd-contaminated alluvial paddy field under annual rice–wheat rotational system. The MgO materials were mixed into the plough-layer soil only once prior to the preceding rice cultivation. Cadmium concentration in wheat grain produced from the non-amendment control exceeded the maximum limit of Cd in wheat grain adopted by FAO/WHO (0.2 mg kg −1). All of the treatments with the MgO materials significantly lowered plant available Cd fraction in the plough-layer soil. However, only the treatment with the commercial MgO at 2250 kg ha −1 produced wheat grain whose Cd concentration was not only significantly lower than that from the control but also less than 0.2 mg kg −1. It is suggested that the significant suppressive effect of the commercial MgO on Cd accumulation in wheat grain would be mainly attributed to its high soil neutralizing capacity as compared to that of MgO-SH-A.

Permanent Carbon Dioxide Storage into Basalt: The CarbFix Pilot Project, Iceland

The storage of large volumes of industrial CO2 emissions in deep geological formations is one of the most promising climate mitigation options. The long-term retention time and environmental safety of the CO2 storage are defined by the interaction of the injected CO2 with the reservoir fluids and rocks. Finding a storage solution that is long lasting, thermodynamically stable and environmentally benign would be ideal. Storage of CO2 as solid magnesium or calcium carbonates in basaltic rocks may provide such a long-term and thermodynamically stable solution. Basaltic rocks, which primarily consist of magnesium and calcium silicate minerals, provide alkaline earth metals necessary to form solid carbonates. In nature, the carbonization of basaltic rocks occurs in several well-documented settings, such as in the deep ocean crust, through hydrothermal alteration and through surface weathering. The goal of the CarbFix pilot project is to optimize industrial methods for permanent storage of CO2 in basaltic rocks. The objective is to study the in-situ mineralization of CO2 and its long term fate. The project involves the capture and separation of flue gases at the Hellisheidi Geothermal Power Plant, the transportation and injection of the CO2 gas fully dissolved in water at elevated pressures at a depth between 400 and 800 m, as well as the monitoring and verification of the storage. A comprehensive reservoir characterization study is on-going prior to the CO2 injection, including soil CO2 flux measurements, geophysical survey and tracer injection tests. Results from the tracer tests show significant tracer dispersion within the target formation, suggesting large surface area for chemical reactions. The large available reservoir volume and surface area in combination with relatively rapid CO2-water-rock reactions in basaltic rocks may allow safe and permanent geologic storage of CO2 on a large scale.

Enhancing process kinetics for mineral carbon sequestration

Abstract The current low-cost process for mineral carbonation involves the direct carbonation of a slurry of magnesium or calcium silicate mineral with supercritical CO 2 . The process is currently limited by the slow reaction kinetics of the carbonation reactions, and in particular the slow dissolution rates of the silicates in weakly acidic conditions. Enhancing the dissolution rate in weakly acidic conditions has been identified as one of the main opportunities for lowering the costs of a direct mineral carbonation process. Serpentine has been identified by its reactivity and abundance as a potential mineral for use in a mineral carbonation process. In this paper we discuss the results of dissolution experiments in which ground serpentine was reacted in weakly acidic aqueous systems containing NH4Cl, NaCl,, sodium citrate, sodium EDTA, sodium oxalate, and sodium acetate. All experiments are carried out at 120 ∘ C and under 20 bars of CO 2 in a batch autoclave. It was found that the sodium salts of citrate, oxalate, and EDTA significantly enhance the dissolution of serpentine under weakly acidic conditions.

The hydromagnesite playas of Atlin, British Columbia, Canada: A biogeochemical model for CO2 sequestration

Anthropogenic greenhouse gas emissions may be offset by sequestering carbon dioxide (CO2) through the carbonation of magnesium silicate minerals to form magnesium carbonate minerals. The hydromagnesite [Mg5(CO3)4(OH)2·4H2O] playas of Atlin, British Columbia, Canada provide a natural model to examine mineral carbonation on a watershed scale. At near surface conditions, CO2 is biogeochemically sequestered by microorganisms that are involved in weathering of bedrock and precipitation of carbonate minerals. The purpose of this study was to characterize the weathering regime in a groundwater recharge zone and the depositional environments in the playas in the context of a biogeochemical model for CO2 sequestration with emphasis on microbial processes that accelerate mineral carbonation.Regions with ultramafic bedrock, such as Atlin, represent the best potential sources of feedstocks for mineral carbonation. Elemental compositions of a soil profile show significant depletion of MgO and enrichment of SiO2 in comparison to underlying ultramafic parent material. Polished serpentinite cubes were placed in the organic horizon of a coniferous forest soil in a groundwater recharge zone for three years. Upon retrieval, the cube surfaces, as seen using scanning electron microscopy, had been colonized by bacteria that were associated with surface pitting. Degradation of organic matter in the soil produced chelating agents and acids that contributed to the chemical weathering of the serpentinite and would be expected to have a similar effect on the magnesium-rich bedrock at Atlin. Stable carbon isotopes of groundwater from a well, situated near a wetland in the southeastern playa, indicate that ∼12% of the dissolved inorganic carbon has a modern origin from soil CO2.The mineralogy and isotope geochemistry of the hydromagnesite playas suggest that there are three distinct depositional environments: (1) the wetland, characterized by biologically-aided precipitation of carbonate minerals from waters concentrated by evaporation, (2) isolated wetland sections that lead to the formation of consolidated aragonite sediments, and (3) the emerged grassland environment where evaporation produces mounds of hydromagnesite. Examination of sediments within the southeastern playa–wetland suggests that cyanobacteria, sulphate reducing bacteria, and diatoms aid in producing favourable geochemical conditions for precipitation of carbonate minerals.The Atlin site, as a biogeochemical model, has implications for creating carbon sinks that utilize passive microbial, geochemical and physical processes that aid in mineral carbonation of magnesium silicates. These processes could be exploited for the purposes of CO2 sequestration by creating conditions similar to those of the Atlin site in environments, artificial or natural, where the precipitation of magnesium carbonates would be suitable. Given the vast quantities of Mg-rich bedrock that exist throughout the world, this study has significant implications for reducing atmospheric CO2 concentrations and combating global climate change.

Hydrothermal preparation of nanotubular particles of a 1:1 nickel phyllosilicate

Hydrothermal treatment of a mixture of nickel chloride, silicic acid and sodium hydroxide at a relatively low temperature, 250 °C and pressure, 10 MPa gave a 1:1 nickel phyllosilicate, [Ni 3Si 2O 5(OH) 4] composed exclusively of hollow, open ended, multiwall nanotubular particles, up to 200 nm in length. No other phases, in particular no silicate platelets were seen. Previous reports on the hydrothermal preparation of tubular nickel phyllosilicate emphasized the need for high temperatures and pressures (ca 400 °C and 70 MPa), with lower temperature giving mostly small thin plate-like products. The tubular particles obtained also had larger outer diameters, 25–30 nm, and larger inner hollow cores, about 10 nm in diameter than nickel silicate nanotubes prepared at high temperatures and pressures. The XRD pattern of the product matched that of pecoraite, the nickel analogue of the tubular magnesium silicate mineral chrysotile. N 2-sorptometry showed the product was mesoporous with a broad range of pore sizes centred around 170 Å, and a BET surface area of 110 m 2/g.

The Assesment for CO2 Sequestration Potential by Magnesium silicate Minerals in Turkey: Cases of Orhaneli-Bursa and Divrigi-Sivas Regions

This paper examines the CO2 sequestration potential of magnesium silicate minerals in Turkey for two example cases, the Orhaneli-Bursa and Divrigi-Sivas regions. The distribution and properties of the silicate mineral deposits are provided and the quantities of CO2 that can be sequestered in these deposits is estimated. The silicate minerals in the Orhaneli and Divrigi deposits provide significant CO2 sequestration capacity. Assuming 100% mineral carbonation efficiency, approximately 2.4 million tons/year of olivine and 6.5 million tons/year of serpentine would be required to sequester the CO2 released by the power plants investigated in this study. Although more detailed studies are needed, it is concluded that this approach has potential given Turkey's large dunite (olivine) and serpentine reserves. Furthermore, the proximity of these deposits and active open-pit mines to thermal power plants emitting CO2 facilitate the utilization of mineral carbonation.

Synchrotron X-ray analysis of norbergite, Mg2.98Fe0.01Ti0.02Si0.99O4(OH0.31F1.69) structure at high pressure up to 8.2 GPa

The natural norbergite, Mg2.98Fe0.01Ti0.02Si0.99O4(OH0.31F1.69) is examined by synchrotron X-ray diffraction analysis at pressures up to 8.2 GPa. The measured linear compressibilities of the crystallographic axes are βa = 2.18(4) × 10−3, βb = 2.93(7) × 10−3, and βc = 2.77(7) × 10−3 (GPa−1), respectively and the calculated isothermal bulk modulus of the norbergite is KT = 113(2) GPa based on the Birch–Murnaghan equation of state assuming a pressure derivative of K′ = 4. The crystal structures of norbergite are refined at room temperature and pressures of 4.7, 6.3, and 8.2 GPa, yielding R values for the structure refinements of 4.6, 5.3, and 5.3%, respectively. The bulk moduli of the polyhedral sites are 293(15) GPa for the tetrahedron, 106(5) GPa for the M2 octahedron, 113(2) GPa for the M3 octahedron, and 113(3) GPa for the total void space. The bulk modulus exhibits a good linear correlation with the filling factor for polyhedral sites in structures of the humite minerals and forsterite, reflecting the Si4+ + 4O2− ⇔ □ + 4(OH, F)− substitution in the humite minerals. Moreover, two simply linear trends were observed in the relationship between bulk modulus and packing index for natural minerals and dense hydrous magnesium silicate minerals. This relationship would reflect that the differences in compression mechanism were involved with hydrogen bonding in these minerals.

Suppressive effects of magnesium oxide materials on cadmium uptake and accumulation into rice grains: I: Characteristics of magnesium oxide materials for cadmium sorption

The objective of this study is to assess the applicability of a commercial magnesium oxide (MgO) and a composite material containing MgO and natural minerals (‘MgO–SH–A’) as the soil amendments for suppression of cadmium (Cd) uptake and accumulation into rice grains. Firstly, the mineralogical and physicochemical properties, soil neutralizing capacities and Cd sorption characteristics of these materials were investigated. Both materials were strongly alkaline and possessed large surface areas. The X-ray diffraction pattern of MgO–SH–A indicated the presence of MgO and a magnesium-silicate mineral (antigorite) as the main components. MgO–SH–A showed a milder soil neutralizing capacity as compared to commercial MgO. The sorptions of Cd on commercial MgO and MgO–SH–A both fitted Langmuir isotherm. The maximum Cd sorption capacity of commercial MgO (46.8 mmol g −1 DW) was higher than that of MgO–SH–A (5.87 mmol g −1 DW), although the latter material showed higher affinity to Cd as compared to the former one. The dominant reaction involved in the Cd sorptions was suggested to be precipitation of Cd(OH) 2 on the material surface. About 40% of Cd sorbed on MgO–SH–A was resistant to desorption by 0.1 M HCl, implying that this portion was strongly retained on the material surface.

Talc at fault

The behaviour of the San Andreas fault varies along its length — it slips in some places and creeps in others. The discovery of the ultrasoft mineral talc in rocks from deep inside the fault could help to explain why. High rates of creep along parts of the San Andreas fault have been attributed to low fault strength associated with serpentinized rocks. This is problematic because the frictional strength of serpentine minerals is considered too high to account for any weakness. Diane Moore and Michael Rymer now report that talc — the soft magnesium silicate mineral familiar in its pure form as talcum powder — may be behind the high creep rate. They discovered talc in serpentinite samples collected during drilling of the SAFOD (San Andreas Fault Observatory at Depth) main hole in 2005. The frictional strength of talc at elevated temperatures is sufficiently low to meet the constraints on shear strength of the fault, and its inherently stable sliding behaviour is consistent with fault creep.

NUMANOITE, Ca4CuB4O6(OH)6(CO3)2, A NEW MINERAL SPECIES, THE Cu ANALOGUE OF BORCARITE FROM THE FUKA MINE, OKAYAMA PREFECTURE, JAPAN

Numanoite, the Cu analogue of borcarite, is found in an irregular patch in crystalline limestone near gehlenite–spurrite skarns at the Fuka mine, Okayama Prefecture, Japan. Numanoite (up to 1 mm across) is observed as a core or zones in borcarite crystals up to 5 mm long. The mineral is also found as veinlets up to 0.4 mm wide in aggregates of borcarite crystals. The associated minerals are nifontovite, bultfonteinite, calcite and an unidentified magnesium silicate mineral. In hand specimen, the mineral is blue-green to colorless and transparent with a vitreous luster. The streak is white to pale blue-green. Numanoite is monoclinic, space group C 2/ m , a 17.794(2), b 8.381(1), c 4.4494(7) A, β 102.42(2)° and Z = 2. The strongest seven lines in the X-ray powder-diffraction pattern [ d in A( I )( hkl )] are 7.57(100)(110), 2.671(84)(421), 2.727(68)(221), 1.887(52)(041,440), 2.272(48)(331), 2.899(44)(600) and 1.698(34)(640). Electron-microprobe and thermogravimetric analyses gave B 2 O 3 24.09, CaO 38.11, CuO 10.32, MgO 1.02, ZnO 0.51, CO 2 15.80, H 2 O 9.75, sum 99.60 wt.%. The empirical formula, calculated on the basis of O = 18, is Ca 3.898 (Cu 0.744 Mg 0.145 Zn 0.036 ) ∑0.925 B 3.969 O 5.615 (OH) 6.208 (CO 3 ) 2.059 , ideally Ca 4 CuB 4 O 6 (OH) 6 (CO 3 ) 2 . The mineral is optically biaxial negative, α 1.618(2), β 1.658(2), γ 1.672(2), and 2 V calc = 60°. The mineral has perfect cleavages in two directions. The density is 2.96(2) g/cm 3 (meas.) and 2.93 g/cm 3 (calc.). The Vickers microhardness is 376 (290–464) kg/mm 2 (25 g load), and the Mohs hardness number is 4½. The differential thermal analysis curve shows two endothermic peaks at 489° and 692°C. It is likely that numanoite from the Fuka mine formed by precipitation from late Cu- and Mg-bearing hydrothermal solutions.

MINERAL CARBONATION AS A POTENTIAL CARBON DIOXIDE STORAGE OPTION FOR THE REGION OF WESTERN MACEDONIA, GREECE

The long-term storage of the greenhouse gas C02 generated by fossil fuel-fired power plants in the form of stable mineral carbonates appears to be a promising option for reducing global CO2 emissions. In the case of mineral carbonation captured gaseous CO2 is chemically stored in an exothermic reaction by the carbonation of magnesium or calcium silicate minerals, forming environmentally benign and thermodynamically stable products. The purpose of this paper is to give an overview of the carbon dioxide storage by mineral carbonation and to examine the feasibility of this sequestration option in the region of Western Macedonia. The main candidate minerals for carbonation and their sequestration capacity are presented. Furthermore, the most promising mineral carbonation process routes as well as the thermodynamics and kinetics of carbonation reaction are addressed, based on a review on the published literature. In Greece abundant magnesium-rich ultramafic rocks exist that probably could support the national CO2 emissions abatement policy. The attractiveness stems from the favourable geographical relationship between large stationary CO2 emission sources and potential magnesium silicate deposits. Thus, a roughly description of the olivine deposits and their quality in the region of Western Macedonia will be provided

English

Norway has a long history of mining dating back to the Akersberg silver mine in Oslo about 1000 years ago. Larger-scale mining for copper and sulfur became common in the early 1600s. There is no active mining of massive sulfide deposits in Norway today; but the operations have left behind tailings, waste rocks and adits that in many cases discharge low-pH, metal-laden waste streams. Three of the Norwegian sulfide mines (Roros, Rana, and Sulitjelma) where mitigation has taken place, but metal release is still evident are discussed in this paper. The Roros Mining District consists of many massive sulfide deposits mined primarily for Cu with minor lead and zinc. Some of the tailings dams have been reclaimed, while others have been left open exposed to weathering. Evidence of oxidation appears in the upper ½ meter in one of the uncovered tailings dams, closed 30 years ago, where pH is 2.5 at the surface increasing to a pH 6 at 70 cm depth. These tailings contain silicate minerals that most likely have a neutralizing potential. The Rana mining area consist of a few smaller massive deposits and a recently closed (2002) nickel deposit associated with a mafic intrusive. Tailings from the nickel mine were emplaced along the shore line. Closure of the tailings included a soil cover 10-20 cm thick. Preliminary investigations indicate that this cover is not efficiently reducing the oxidation of sulfide minerals. Magnesium silicate minerals are most likely, however, neutralizing the acid generated from pyrrothite, the main sulfide in the ore. The Sulitjelma Mining District also consists of many massive sulfide deposits mined until 1991. Reclamation of the mining district includes a one meter cover on the tailings dam and the discharge of ARD into old underground mine workings. This has resulted in a mass loading reduction of 80-90%. Characterization of these sites has primarily focused on surface water quality, and in some instances, groundwater quality. The water quality data combined with mineralogical, geochemical, and hydrogeological data of the ore deposit and waste material can be used to improve mitigation, resulting in better control of metal release.

Crystalline silicates in comets: How did they form?

Two processes have been proposed to explain observations of crystalline silicate minerals in comets and in protostellar sources, both of which rely on the thermal annealing of amorphous grains. First, high temperatures generated by nebular shock processes can rapidly produce crystalline magnesium silicate grains and will simultaneously produce a population of crystalline iron silicates whose average grain size is ∼10–15% that of the magnesium silicate minerals. Second, exposure of amorphous silicate grains to hot nebular environments can produce crystalline magnesium silicates that might then be transported outward to regions of comet formation. At the higher temperatures required for annealing amorphous iron silicates to crystallinity the evaporative lifetime of the grains is much shorter than a single orbital period where such temperatures are found in the nebula. Thermal annealing is therefore unable to produce crystalline iron silicate grains for inclusion into comets unless such grains are very quickly transported away from the hot inner nebula. It follows that observation of pure crystalline magnesium silicate minerals in comets or protostars is a direct measure of the importance of simple thermal annealing of grains in the innermost regions of protostellar nebulae followed by dust and gas transport to the outer nebula. The presence of crystalline iron silicates would signal the action of transient processes such as shock heating that can produce crystalline iron, magnesium and mixed iron–magnesium silicate minerals. These different scenarios result in very different predictions for the organic content of protostellar systems.

Carbonation of Magnesium Silicate Minerals: An Experimental Study

AbstractCO2 sequestration by magnesium silicate mineral is the only known process that can permanently store CO2 using a natural feedstock that exists in sufficient quantities to be used practically. Transporting large amounts of mineral over long distances is uneconomical. For Canada to benefit from such a process, identification of suitable Canadian magnesium silicate mineral deposits is crucial. Only carbonation under pressure in NaCl and NaCl/NaHCO3 solutions results in high Mg conversions (40–80%). Among the minerals examined in this study, the serpentines reacted most easily, and peridotite was the most difficult to carbonate. Increasing carbonation pressure to very high levels reduced the degree of carbonation as hydrolysis reactions became competitive with the carbonation process.

Interfacial-chemistry mediated behavior of colloidal talc dispersions

Interfacial chemistry and rheological behavior of talc suspensions as a function of pH, talc solid content, and type and concentration of ions have been investigated using electrokinetic measurements, rheology, settling behavior, and solution analysis. Zeta potential measurements show a strong dependence on the pH history of the talc suspension that only occurs when the surface area (solid content) of the talc is high. Particle interactions measured through dispersion yield stress measurements show a similar dependence. Talc is a magnesium silicate mineral and the dependence seen in the electrokinetic properties in this study has been attributed to Mg(II) dissolution at low pH, and has been confirmed by solution analysis. At high solid content ( > 20 wt% ), pronounced Mg(II) ion dissolution occurs at low pH values. Formation and adsorption of electropositive Mg(II) hydrolysis products occurs at high pH (>9), and these lead to zeta potential reduction and, at high solid contents, charge reversal. Particle interactions reflect the surface chemistry behavior. Consequently, for a freshly prepared suspension at high pH, the yield stress is lower compared to after the pH has been taken to 5 and subsequently increased.

Sampling and flotation testing of Sudbury Basin drill core for process mineralogy modelling

The area of flotation testing of drill core is important in the business plan of most mining companies. Metallurgical information derived from this practice can be used to advantage in strategic decision-making. Sampling, flotation testing and subsequent QemSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) analysis of a mineral resource is one example of this approach. A new resource, located in Sudbury, Ontario, is being assessed for the Sudbury Operations of Falconbridge Limited, which includes the Strathcona Mill. In this case, it was possible to improve the value of information from sampling and flotation testwork by using an improved, statistically-based test design, by sampling the resource by generic end-member ore type, and by integrating the Mineral Processing and Mineral Science disciplines into a Process Mineralogy team. In addition to producing standard metal grade and recovery information, this new approach provides more reproducible information from representative samples and flotation testing in a replicate format. QemSCAN technology is used to produce a size by size mineral balance, including both modal percentages and liberation, from which flotation models for each ore type can be developed. As a result, a key understanding of the potential behaviour of a given ore type, if mined and then processed at the current mill operation, is gained at the 95% confidence level. The three ore types of this mineral resource were shown to have different flotation characteristics. Quantifying the mineralogy and liberation in each of the three ore types, has shown that this difference is due to changes in modal percentages of ferro-magnesium and magnesium silicate minerals such as pyroxene, talc and serpentine. Liberation across the three ore types is very similar and is therefore not responsible for variation in flotation performance.

Synthesis of Phosphor Materials Using Natural Ore "Serpentine".

Serpentine is a hydrated ultra-mafic rock, which is primarily composed of magnesium silicate minerals such as chrysotile and antigorite. Fibrous chrysotile is the most common type of asbestos. Since the rich mines supplied serpentine in Japan, application of natural ore “serpentine” as raw materials for ceramics has one of the potentially lowest cost ceramics production. In this study, long afterglow phosphor, Sr2MgSi2O7, has been successfully synthesized using natural ore serpentinite. Eu2+ and Dy3+ co-doped compounds show long-lasting phosphorescence. This demonstrates that the “serpentine” could be used in preparing alkaline earth silicate phosphors.