Open Access Minerals That Host Metals At Dorowa Rock Phosphate Mine .
The Open Mineralogy Journal, 2011, 5, 1-91Open AccessMinerals that Host Metals at Dorowa Rock Phosphate Mine, ZimbabweM. L. Meck*,1,2, J. Atlhopheng2, W. R. L. Masamba3, S. Ringrose3 and S. Diskin31Department of Geology, University of Zimbabwe, P.O. Box MP167, Mt. Pleasant, Harare, Zimbabwe2Environmental Science Department, University of Botswana, Private Bag UB0704, Gaborone Botswana3Harry Oppeinheimer Okavango Research Centre (HOORC), University of Botswana, Private Bag 285, Maun BotswanaAbstract: This study set out to establish the major minerals at Dorowa and determine which of those are likely to hostmetals that may leach into surface and groundwater. This study comes after a preliminary assessment of the water qualityin the Save River downstream of the Dorowa phosphate mine in Zimbabwe showed an increase in conductivity, ironcontent, manganese content, nitrates and hardness when compared to those taken before the mining area. X-RayDiffractometry (XRD) was used to establish the major minerals at Dorowa whilst Inductively Coupled Plasma MassSpectrometry (ICP- MS) was used to establish the chemistry of the rocks. The results from this study show that the majorminerals in the rocks around Dorowa are feldspars, pyroxenes, apatite, magnetite and calcite. The metals hosted by therocks include Ag, As, Be, Cd, Co, Cu, Pb, Hg, Ni, Sb, Se and Zn. The study concludes that the minerals likely to hostmetals are calcite and apatite. Metal hosting is higher in apatite minerals than in calcite. Metal hosting by the otherminerals observed in the study area is low.Keywords: Igneous Rock phosphates, metal host.INTRODUCTIONIgneous rock phosphates are currently being mined atDorowa mine in Zimbabwe (Fig. 1). The measured rockphosphate resource at Dorowa is 73 million tonnes phosphate rock with an average grade of 6.6% P2O5 givingapproximately 4.82 million tonnes P2O5 [1]. According to [2]and [3] rock phosphates may contain heavy and radioactiveelements considered to be toxic to humans and animals. Theheavy metal and radionuclide content varies according to thegeologic setting of the mining area [4-8]. In general, sedimentary phosphates contain much higher concentrations ofpotentially harmful elements (Cd, Cr, Se, and U) thanigneous phosphates [9-12]. Although sedimentary phosphates are characterized by a significantly higher content of:Be, Cd, Cr, Ni, Mo and U, compared to igneous phosphates,the latter still contain a substantial amount of these heavymetals [13,14]. Apatite mining on the Khibiny apatite–nepheline ore deposits in NW Russia has affected groundwaters near the mines through elevated concentrations oftotal dissolved solids and metals [14]. These observationstogether with the fact that approximately one fifth of theworld’s marketable phosphate production is derived fromigneous rocks [13,15] make the study of igneous rockphosphate a necessity. Although there are numerous studieson heavy metals in sedimentary and igneous phosphates,there are a relatively limited number of references dealingwith the actual minerals that host the heavy metals. Thephosphates at Dorowa are mined from an alkaline ringcomplex that possesses structural, petrological, mineralo*Address correspondence to this author at the Department of Geology,University of Zimbabwe, P.O. Box MP167, Mt. Pleasant, mails:maideyimeck@yahoo.com or mabvira@science.uz.ac.zw1874-4567/11gical and geochemical features similar to other igneousphosphate deposits known in the world. Therefore resultsfrom this study can be extended to these other deposits.Though substantial work on the mineralogy of theDorowa ring complex has been carried out [16-21], prior tothis study there was no data available on those mineralspotentially hosting heavy metals from this ring complex.Thus this work set out to determine the major minerals atDorowa mine and identify those that have a potential ofhosting metals and make the study a basis for applying toother phosphate deposits of igneous origin. The knowledgeof metal host is vital as it gives an insight on fate of metals.The results from this study will be used to predict the longterm impacts of mining activities around Dorowa Mine,particularly with respect to the quality of drinking water.Around the study area (Dorowa), most villagers use the SaveRiver as their primary drinking water source.GEOLOGYSAMPLINGOFTHERINGCOMPLEXANDThe study area is Dorowa Mine, situated in the catchmentof the Save River, Zimbabwe (Fig. 1). The area is located inthe Buhera District of Zimbabwe at 19 04'S; 31 46'E. Thegeology of the Dorowa alkaline ring complex was investigated in detail by [17] and [21].The mine is exploiting a Mesozoic carbonatite that isassociated with foyaite, ijolite and pulaskite [18]. Thecalcium carbonate plug forms a very small portion of thecomplex and the foyaites and ijolites have been extensivelymineralized with phlogopite, vermiculite and apatite. Themain rock being mined at Dorowa is fluoro-apatite (Ca5(PO4)3(OH, F, Cl) rock which comprises more than 50% ofthe apatite. Carbonate and hydroxyl apatite are also present2011 Bentham Open
2The Open Mineralogy Journal, 2011, Volume 5Meck et al.SAVE sapeTOWNSMutareUSUBCATCHMENT ESANYATIRUNDEChimanimamiERW ELO UDYAREAODZIVESACATCHMENT BOUNDARY050ChipingeN100kmSOUTH AFRICAFig. (1). Study area Dorowa in the Save Catchment of Zimbabwe.[22]. Mining is concentrated in two main centres within thesyenite fenite known as the North and South Pits. In theNorth Pit apatite occurs with vermiculite in the form ofdykes, veins and stringers [17] whilst in the South Pit itoccurs with pyroxene. Fig. (2) shows a sketch map of thegeology of the Dorowa Complex.The main rock types in the area are pyroxenites, igneouscarbonatites, iron bearing rocks and alkaline syenites [18,20]. These rocks are intersected by carbonates, feldspar veinsand ultramafic dykes. The relationship between the differentrock types is very complex. Nevertheless, during samplingan attempt was made to sample from all the major rockstypes that could be visually distinguished. The followingrock types were sampled; syenite, pyroxenite, apatite rock,carbonatite, magnetite rock and dolerite. Based on themineralogy five syenites, three pyroxenites, two apatitebearing rocks, two dolerites, one carbonatite and onemagnetite bearing rock were analyzed.Analytical MethodsThe rock samples were crushed and split into fractions byconing and quartering. The sample size was determined bythe variability of the rock. In all cases it was ensured that thetotal sample for a rock was sufficient to properly characterizethe rock described. The rock samples were ground andpulverized to pass through a 180 µm sieve. To minimizecontamination, an agate mortar and pestle was used forgrinding and pulverizing the samples.X-ray diffraction was used to identify the major mineralspresent. The X-ray diffraction (XRD) patterns were recordedon un-oriented powder using an X'Pert Quantify Diffractometer with a Gonio Scan Axis operating at 30 mA and 40 kVusing CuKα radiation. The samples were scanned in therange, 3-80 , 2θ using a continuous scan step size of 0.02 2θ and scan step time of 0.5s. The method used identifies allphases greater than 2% in the sample. The phases wereindexed using Diffrac-AT software linked to a JCPDSdatabase. XRD scans were matched, based on the so-called"figure-of-merit" with a standard mineral database [ICDDPDF2 (2002)]. All phases indicated to be present in a samplewere evaluated by verifying peak by peak to see if there wasa close match with the powder diffraction file.ICP- MS was used to analyze for the metals in the rocksamples. The metals analyzed for in this study are those thatare of concern to plant, animal and human health. [23]prioritized the following elements as the most toxic from the
Minerals that Host Metals at Dorowa Rock Phosphate Mine, ZimbabweThe Open Mineralogy Journal, 2011, Volume 53NExplanationFoyalite, ijolite, carbon atitedykes pulaskitic feniteCarbonatite plug and dykesMtMtM agnetite and magnetiticserpentinite (Mt)Syenitic feniteMtApatite & vermiculite mineralisedSyenitic feniteMtQuartz - syenitic feniteFenitised MashonalandDoleriteGeological boundary - gradationalMtOpencast pit wallMt200Scale of metres2000400Fig. (2). Sketch Geology map of the Dorowa Carbonatite after [21].standpoint of potential hazard to plants and human healthy:arsenic (As), beryllium (Be), antimony (Sb), cadmium (Cd),chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), nickel(Ni), selenium (Se), silver (Ag), and zinc (Zn). [24]classified metals according to toxicity and availability intothree categories namely: non critical; toxic but insoluble orvery rare; and very toxic and relatively accessible. Their verytoxic and relatively accessible category contained beryllium(Be), cobalt (Co), nickel (Ni), zinc (Zn), tin (Sn), arsenic(As), selenium (Se), tellurium (Te), palladium (Pd), silver(Ag), cadmium (Cd), platinum (Pt), gold (Au), mercury(Hg), thallium (To), lead (Pb), antimony (Sb) and bismuth(Bi) in specific forms. The elements common in the twoclassifications are Ag, As, Be, Cd, Co, Cu, Pb, Hg, Ni, Sb,Se, and Zn. Thus these metals were analyzed for in thisstudy. Hg was not analyzed for due to unavailability of theappropriate equipment.RESULTSPhases detected by the XRD analysis in the 14 rocksamples are summarized in Table 1. A summary of mineralsfound in the ring complex are given in Table 2 which alsolists the observed chemical formula, and the group to whichthe observed mineral belongs. The major minerals at Dorowaare feldspars, pyroxenes, apatite, magnetite and calcite.Feldspars and pyroxene are present in 11 out of 14 samples.In 8 of the samples apatite minerals were found. In threesamples, small peaks corresponding to clays (which areprobably alteration products of the magmatic minerals) wereobserved. Though the clay mineral could be identified asmontmorillonite in one of the rocks (Meck 2), the peaks inthe other two rocks (Meck 9 and Meck 12) were insufficientto allow determination of the mineral present. The XRDresults show the presence of fluor-apatite and hydroxylapatite in the Dorowa Complex. These observations compare
4The Open Mineralogy Journal, 2011, Volume 5Meck et al.Table 1. Minerals Picked Up by XRD in the Different Rock SamplesSample NameMinerals Picked by XRDRock NameMeck1calcium carbonate, fluoro-apatiteSyeniteMeck2fluorapatite, Ce-rich, augite, albite, montmorilloniteDoleriteMeck3Albite intermediate, , sodium tecto-alumosilicate, diopside, apatitePyroxeniteMeck4iron diiron(III) oxide, magnetite low, syn, iron III hydrogen oxide, magnetiteMagnetititeMeck5Albite, ordered, augiteSyeniteMeck 6Diopside, aluminian, syn, augite, albite, flourapatite, bytownite, enstatitePyroxeniteMeck 7Hydroxyl apatite, syn, iron diiron(III) oxidePhosphate rockMeck 8Augite Hydroxyl apatite, syn Albite, orderedPyroxeniteMeck 9Calcite, Montmorillonite-15ACarbonatiteMeck 10Diopside, aluminian, Hydroxyl apatite, Albite, orderedDoloriteMeck 11Albite, calcian, augite, lazurite, nephelineSyeniteMeck 12Albite, ordered, Anorthoclase, disordered, MontmorilloniteSyeniteMeck 13Albite, calcian, ordered Orthoclase, Augite, aluminianSyeniteMeck 14Hydroxyl apatite, syn Actinolite, Magnetite, syn, α-Si O 2, quartz HPPhosphate RockTable 2. Major Minerals in the Dorowa Ring ComplexMineral/ CompoundGroup/FamilyGeneral FormulaEmpirical FormulaMinerals Observed in this StudyAugiteSilicate(Ca, Na)(Mg, Fe, Al,Ti)(Si,Al) 2O6Ca0.9Na0.1 Mg0.9 Fe2 0.2Al0.4 Ti0.1Si1.9O6(Mg,Al,Fe,Ti,Cr)Ca,Na,Fe,Mg)(Si,Al)2 O 6Mg.927Ca.818 Al.078 Fe.069 Na.06 Cr .04Ti.008 Si2 O6Calcium hateCa5(PO 4)3 FCa5(PO 4)3 FCa9.653Ce0.327Na0.02(Si0.32 P5.68O24)F1.48(O H)0.52Ca5(PO 4)3 F.94 Cl.1AlbiteSilicateNaAlSi3O 8Na0.95 Ca0.05Al1.05Si2.95O8(Na0.98 Ca0.02)(Al1.02Si2.98O 8)Na Al1.08 Si2.92 O8DiopsideSilicateCaMgSi2O6CaMg(Si2O6)Ca Mg(Si O3) 2Ca (Mg , Al) ( Si, Al)2 O6ApatitePhosphateCa5(PO 4)3(OH,F,Cl)Ca5(PO 4)3(OH) 0.3333F0.3333Cl0.3333Ca5 (F, Cl) P3 O 12Iron di iron (III) oxideOxideFeO·Fe2 O3FeO·Fe2 O3Fe3 O 4MagnetiteOxideFe Fe 2O4Fe3 2Fe 2 O 4Fe3 O 4EnstatiteSilicateMg2Si2O6Mg2Si2O6Mg31.88 Sc2.72 Si32.04 O 100Hydroxyl apatitePhosphateCa5(PO 4)3(OH)Ca5(PO 4)3(OH)Ca9.42 Sr 0.18H0.4(PO 4)6(OH)1.60Montmorillonite-15AClay(Na,Ca)0,3 (Al,Mg)2 Si4O 10(OH)2·n(H2O)Na0.2Ca0.1Al2Si4O10 (OH) 2(H2O)10Ca0.2(Al,Mg) 2 Si4 O 10 (OH)2·4 H 2ONa3CaAl3 Si3O 12 SLazuriteSilicateNa3Ca(Al3 Si3O 12)SNa3CaAl3 Si3O 12 SAnorthoclaseSilicate(Na,K)AlSi3O8Na0.75K 0.25AlSi3O 8(Na,K)(Si3Al)O 8NephelineSilicate(Na,K)AlSiO4Na0.75K 0.25Al(SiO 4)Na3 K Al4 Si4 O16ActinoliteSilicateCa2(Mg,Fe ) 5Si8O22(OH)2Ca2Mg3 Si8O 22(OH)2 Fe2 2Ca (Mg, Fe 2) Si2O6·2 (Mg, Fe) SiO3QuartzSilicateSiO2SiO2á-Si O 2Iron(III) hydrogenOxideOxidewell with the work done by previous researchers [16-18, 20]and observations elsewhere in the world which shows thatfluor-apatite is the dominant apatite in crustal rocks butoccurs with hydroxyl apatite in most cases [15].The ICP-MS results shows that most rocks at Dorowa areassociated with the metals Ag, As, Be, Cd, Co, Cu, Pb, Ni,Fe1.98 H 0.06O3Sb, Se, Zn. Fig. (3) shows the metals associated with thedifferent rocks analyzed. The data shows that the rocks Meck3, Meck 4, Meck 9 have the highest metal levels. Analysis ofthe XRD results in table 1 show that these rocks containmagnetite, calcite and apatite. Meck 1, Meck 2, Meck 5 andMeck 10 have the lowest metal levels. These rocks are either
Minerals that Host Metals at Dorowa Rock Phosphate Mine, ZimbabweThe Open Mineralogy Journal, 2011, Volume 55200180concentration in Fig. (3). Metal levels in the different rocks around Dorowa.dolerites or syenites with very low amounts of apatiteminerals. The rocks with flouro apatite (Meck, 1, Meck2,and Meck6) have generally lower metal levels than thosewith hydroxyl apatite (Meck 7, Meck 8 and Meck 14).(4) gives a graphical representation of the levels of metalsobtained in this study alongside average heavy metalconcentrations in phosphate rock (PR) deposits cited by [4].A comparison of the metal levels in the rock phosphate atDorowa obtained in this study with rock phosphates fromother places in the world shows that the levels obtained inthis study are within the average levels of similar rocks. Fig.DISCUSSIONBased on the evidence presented from the XRD scansand the ICP-MS results a good case can be made that the450400concentration in ppm350AsCd300Cr250Cu200PbHg150Ni100V50Zn0Meck 7 Meck 14Russia(Kola)USASouthAfricaMorocco Other N.AfricaMiddleEastFig. (4). Metals levels in the two rock phosphates from the study area alongside average heavy metal concentrations in phosphate rock (PR)deposits cited by [4] as data obtained by Kongshaug et al., 1992.
6The Open Mineralogy Journal, 2011, Volume 5Meck et al.culprit minerals are magnetite, calcite and apatite. The rockswith these minerals have higher metal content. Fig. (5)shows the total metal content for the rocks in the ringcomplex.The carbonatite and apatite bearing rocks (Meck 3, Meck4, Meck 9) have higher levels of metals compared to theother rocks. Analysis of the phases present in the rocksshows that the carbonatite Meck 9 contains lower total metalcontent when compared to Meck 3 and Meck 4 which areapatite bearing rocks. This data is therefore implying that theminerals with higher potential of hosting metals in theDorowa complex are apatite and calcite. Both results in XRDand ICP-MS results concur that calcite and apatite are likelyto host metals. The XRD data presented in Table 2 showsthat the various apatites found in the study area have a sitethat is hosting trace elements further confirming that theseapatites have a potential for hosting metals. The data is alsoindicating that metal hosting is lower in calcite minerals andhigher in apatite minerals.The crystal-chemistry of the two minerals (calcites andapatites) were scrutinized to explain metal hosting in theseminerals making use of literature by [23-40] that summarizesthe mechanisms of element incorporation in carbonates,phosphates, and silicates. The literature provides thefundamental constraints on reactions such as sorption, coprecipitation, crystal growth, and dissolution; thus dictatingthe elements hosted.Phosphates SubstitutionApatite is more likely to host the metals because itsstructure is characterized by various substitutions (e.g. Sr 6 or Ba 6 for Ca2 ; (SiO4) 4- for (PO4)6- and Cl- or F- for (OH))without a significant alteration to its basic structure. Thus itcan bind many toxic metals into stable mineral structures.There are two distinct Ca sites in the apatite structure i.e. theCa1 site which is coordinated by nine O atoms and the Ca2site which is coordinated by six O atoms. The size andgeometry of the Ca2 site varies, depending on the columnanion. Ca may be substituted by K, Na, Mn, Ni, Cu, Co, Zn,Sr, Ba, Pb, Cd, Sn, Y, and Rare Earth Elements (REE).Substitution of trivalent cations such as REE for Ca2 hasbeen shown to be coupled with substitutions of Na f or Ca2 [41, 42]. The structure also allows elements such as arsenicand chromium to be substituted by exchanging with thephosphate ions. Substitution of metals in apatite and theresultant diverse compositions are described by [43-50]. Sizelimit related the anion and cation radius for phosphates areelaborated by [51-53].Carbonate SubstitutionSeveral studies have been carried out to consider elemental substitution within calcite structure carbonates [54-59]and conclude that substitution is controlled primarily bygross features of the crystal structure. The crystal structure ofmany carbonate minerals reflects the trigonal symmetry ofthe carbonate ion, which is composed of a carbon atomcentrally located in an equilateral triangle of oxygen atoms[60]. According to [53] the range of radius ratio that cansubstitute in the structure is 0.155- 0.225Å. Alkaline earthelements in carbonates can be substituted by the 3-dtransition metals [61]. The carbonate anion group usuallyoccurs in combination with calcium, sodium, uranium, iron,aluminum, manganese, barium, zinc, copper, lead, or therare-earth elements [60]. Relatively common carbonateminerals serve as metal ores: siderite, for iron; rhodochrosite,for manganese; strontianite, for strontium; smithsonite, forzinc; witherite, for barium; and cerussite, for lead.Total metal450400350300250200Total metal150100500Meck Meck Meck Meck Meck Meck Meck Meck Meck Meck Meck Meck Meck Meck12345678910 11 12 13 14Fig. (5). Total metal content in the different rock types at Dorowa.
Minerals that Host Metals at Dorowa Rock Phosphate Mine, ZimbabweSubstitution depends on chemical composition, crystalstructure, pressure and temperature [34, 62]. Substitution ofthe metal ions therefore occurs in the Ca site [62,63]summarize the comparative compressibility’s of calcitestructure carbonates and notes that relaxation around an“impurity” ion is localized, and the corner-sharing structuraltopology of calcite facilitates the observed wide spectrum ofimpurity substitution. Though the calcite-structure carbonates represent a mineral group that is structurally differentfrom oxides and silicates, the Mg-Fe substitution in calcitestructure is similar in magnitude to that in silicate spinelswhich means the absolute difference is typically no morethan a few percent for complete substitution [64].Co-precipitation experiments from aqueous solution atroom temperature reveal that divalent Co, Zn, Cd, and Baexhibit different preferences for incorporation amongmultiple surface sites present on the calcite face during spiralgrowth [65]. Experimental work on the co- precipitation ofdivalent Co, Zn, Mn, Fe, Cd, Sr, Pb, and Ba with Ca incalcite has shown strongly selective uptake in structurallydistinct surface sites on the calcite. Despite distinct surfacesite preferences and uptake patterns varying in magnitude bymore than a factor of ten, bulk coordination differs onlyminimally [66] have also shown that trapping can also leadto metal hosting in minerals when he showed a calcitedeposit trapping traces of Pb, Zn and Cd[(Ca, nPb, nZn,nCd)]CO3 during carbonation. The major carbonate in thestudy area is calcite thus significant trapping and substitutionof potential pollutants is possible.This study has established the minerals potentially hosting toxic metals. Chemical data provided has shown that thelevels of metals are higher in the rocks that contain calciteand apatite. The discussion has elaborated mechanisms bywhich the metals are hosted in the calcite and apatiteminerals.CONCLUSIONThis paper presents an insight into the minerals that arelikely to host the metals in the study area. It is an importantstep needed prior to modeling because it enables the determination of the suppositions needed for the model, as itprovides evidence concerning the minerals that controlpotential pollutants. The carbonates and phosphates havebeen identified as the potential pollutant host minerals. Highgrade quality rock phosphate deposits are being depletedworldwide due to increased agricultural activities, so moreand more mining companies are turning to lower qualitysources and more to igneous rock phosphates. Because mostrock phosphates of igneous origin are associated with severalminerals, use of them as a source for phosphate-fertilizersincrease the use of minerals that may contain heavy metals.The study has shown an increase in conductivity, iron content, manganese content, nitrates and hardness downstreamof the study area. Thus deductions from this study andsimilar studies can be used to quickly pinpoint the mineralsthat host the pollutants and therefore take the necessaryprecautions. It should also be noted that as much as twothirds of the world’s known phosphate resources arecomposed of carbonate rich phosphate rock therefore exploitation of these deposits, provides a potential for contamina-The Open Mineralogy Journal, 2011, Volume 57tion of the areas surrounding the mines and also areas wherethey are used by increasing heavy metal levels.ACKNOWLEDGEMENTSThe work is being carried out as part of a regional studyof Sustainable Integrated Management of Arid and SemiArid Region of southern Africa (SIMDAS) funded by theUnited Nation Education and Scientific Cooperation(UNESCO) and developed for the SADC region. Theauthors acknowledge UNESCO for funding the project. Wealso acknowledge the University of Zimbabwe and theUniversity of Botswana for co-ordinating the 11][12][13][14][15][16]Appleton, J.D. 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]The Open Mineralogy Journal, 2011, Volume 5Johnson, R.L. The geology of the dorowa and shawa carbonatitecomplexes Southern Rhodesia. Transact. Proceed. Geol. Soc. SouthAfrica, 1961, 64, 101-146.Barber, B. Phosphate resources of Zimbabwe. Fert. Resou., 1991,30, 247-278.Walsh, K.L.; Siegfried, P. Hall; R.P.; Hughes, D.J. Tectonicimplications of four recently discovered carbonatites along theZambezi escarpment fault, northern Zimbabwe. J. Afr. Health Sci.,2001, 32, 36-37.Fernandes, T.R.C. In: Dorowa and Shawa: late Palaeozoic toMesozoic carbonatite complexes in Zimbabwe. Notholt, A.J.G.;Sheldon, R.P.; Davison, D.F., Eds.; Phosphate deposits of theworld: Phosp. rock resou. Cambridge University Press, Cambridge:UK, 1989, Vol. 2, pp. 176-178.Lauderdale, J.N. The Geology of the country around Dorowa andShawa, Buhera district. Zim. Geol. Surv. Bull. 95., Residual effectsof novel phosphate.Fernandes, T.R.C. Electron microscopy applied to the beneficiationof apatite ores of igneous origin. Transact. Geol. Soc. S. Afr., 1978,81, 249-253.McBride, M.B. Environ. Chem. Soils., Oxford University Press:New York, 1994.Dallas, H.F.; Day, J.A. The effect of water quality variables onRiverine ecosystems: a review. Fresh water research unit. Wat. Res.Comm. Rep. TT61/93, University of Cape Town: S.A. 1993.Kersten, M.; Moor, H.C.; Johnson; C.A. Speciation of trace metalsin leachate from a MSWI bottom ash landfill. Appl. Geochem.,1997, 12, 675-683.Feallman, A.M. Leaching of chromium and barium from steel slagin laboratory and field tests: a solubility controlled process? WasteManage., 2000, 20, 149-154.Crannell, B.S.; Eighmy, T.T.; James, E.; Krzanowski, J.; Eusden,Jr. D.; Shaw, E.L.; Francis, C.A. Heavy metal stabilization inmunicipal solid waste combustion bottom ash using solublephosphate. Waste Manage., 2000, 20, 135-148.Freyssinet, P.H.; Piantone, P.; Azaroual, M.; Itard, Y.; ClozelLeloup, B.; Guyonnet, D. Chemical changes and leachate massbalance of municipal solid waste bottom ash submitted toweathering. Waste Manage., 2002, 22, 159-172.Piantone, P.; Bodnana, F.; Chatelet-Snidarob, L. Mineralogicalstudy of Major mineral phases from weathered MSWI bottom ash:implications for the modeling and trapping of heavy metals. Appl.Geochem., 2004, 19, 1891-1904.Goldschmidt, V.M. The principles of distribution of chemicalelements in minerals and rocks. J. Chem. Soc. Lond., 1937, 1, 655673.Ringwood, A.E. The principles governing trace element distribution during crystallization. The influence of electronegativity.Geochimic. Cosmochimic. Acta., 1955, 7, 189-202.Burns, R.G. Mineral. Applicat. Cryst. Fiel. Theo., CambridgeUniversity Press, Cambridge: UK, 1970, pp. 144-174.Burton, J.A.; Prim, R.C.; Slichter, W.P. The distribution of solutein crystals grown from the melt. I- Theoretical. J. Chemic. Phys.,1953, 21, 1987- 1991.Zhang, J.; Reeder; R.J. Comparative compressibilities of calcitestructure Carbonates: deviations from empirical relations. Am.Mineral., 1999, 84, 861-870.Nakamura, Y. Origin of sector zoning in igneous clinopyroxenes.Am. Mineral., 1973, 58, 986-990.Dowty, E. Crystal structure and crystal growth. II. Sector zoning inminerals. Am. Mineral., 1976, 61, 460-469.Dowty, E. The importance of adsorption in igneous partitioning oftrace elements. Geochim. Cosmochim. Acta., 1977, 41, 1643-1646.Reeder, R.J.; Grams, J.C. Sector zoning in calcite cement crystals:Implications for trace element distributions in carbonates.Geochim. Cosmochim. Acta., 1987, 51, 187-194.Paquette, J.; Reeder, R.J. A new type of compositional zoning incalcite: Insights into crystal-growth mechanisms. Geology, 1990,18, 1244-1247.Reeder, R.J.; Lamble, G.M.; Northrup, P.A. XAFS study of thecoordination and local relaxation around Co2 , Zn2 , Pb2 , and Ba2 trace elements in calcite. Am. Mineral., 1999, 84, 1049-1060.Ronsbo, J.G. Coupled substitutions involving REEs and Na and Siin apatites in alkaline rocks from the Ilimaussaq intrusion, SouthMeck et reenland, and the petrological implications
The data shows that the rocks Meck 3, Meck 4, Meck 9 have the highest metal levels. Analysis of the XRD results in table 1 show that these rocks contain magnetite, calcite and apatite. Meck 1, Meck 2, Meck 5 and Meck 10 have the lowest metal levels. These rocks are either Table 1. Minerals Picked Up by XRD in the Different Rock Samples
sian minerals. All minerals, however, can be classified into two main groups—silicate minerals and nonsilicate minerals—based on the chemical compositions of the minerals. Silicate Minerals A mineral that contains a combination of silicon, Si, and oxy-gen, O, is a silicate mineral. The mineral quartz has only silicon and oxygen atoms.
Hosts Your cluster's hosts perform different functions. Master host: An LSF server host that acts as the overall coordinator for the cluster, doing all job scheduling and dispatch. Server host: A host that submits and executes jobs. Client host: A host that only submits jobs and tasks. Execution host: A host that executes jobs and tasks. Submission host: A host from which .
IAS 36 – LỖ TỔN THẤT TÀI SẢN. xxx KHÔNG áp dụngcho Ápdụngcho x Hàng tồnkho (IAS 2) x . Tài sản tài chính (IFRS 9) x . Quyền lợi người lao động (IAS 19) x . Tài sản thuế hoãn lại (IAS 12) x . Hợp đồng xây dựng (IAS 11) x . Bất động s
COUNTY Archery Season Firearms Season Muzzleloader Season Lands Open Sept. 13 Sept.20 Sept. 27 Oct. 4 Oct. 11 Oct. 18 Oct. 25 Nov. 1 Nov. 8 Nov. 15 Nov. 22 Jan. 3 Jan. 10 Jan. 17 Jan. 24 Nov. 15 (jJr. Hunt) Nov. 29 Dec. 6 Jan. 10 Dec. 20 Dec. 27 ALLEGANY Open Open Open Open Open Open Open Open Open Open Open Open Open Open Open Open Open Open .
Silicate Minerals Silicate minerals make up 96% of the earth’s crust. Contains atoms of Silicon (Si) and Oxygen (O). Silicate minerals are generally shinny therefore most are found in jewelry. Non-Silicate Minerals Non-silicate minerals only make up 4% of the earth’s crust. However, these minerals are used most widely in
2. some are composed of nonmineral matter a. obsidian, pumice and coal iii. composition and structure of minerals a. nearly 4,000 minerals b. elements 1. basic building blocks of minerals 2. 112 are known, 92 are naturally occurring 3. some minerals are made entirely of one atom 4. most elements are not stable, and thus most minerals are a
For any inquiry regarding the servicing and repair of Metso Minerals Slurry pumps please contact the local Metso Minerals Branch. For information on the Metso Minerals Branch closest to you, contact one of the Metso Minerals Global Sites listed below: Metso Minerals Industries,
minerals (fluorspar, mica, certain limestones and gypsum, heavy minerals in placer form, uranium, bentonite, silica sand, and gemstones) and certain uncommon varieties of minerals (e.g. dimension stone, pumice, pumicite, and cinder deposits). Other minerals include those often used as indus
