Talc Bodies Research Articles

Evaluation of asbestos exposure resulting from simulated application of spiked talcum powders

This study characterizes airborne asbestos exposures resulting from the adult application of cosmetic talc body powders spiked with known concentrations of tremolite. Raw talc ores were spiked with 0.005% and 0.1% asbestiform or non-asbestiform tremolite. Personal samples were collected during 16 simulated events, including puff and shaker application and associated clean-up activities. Airborne fiber levels (PCM) were not significantly different for simulations involving talc spiked with asbestiform and non-asbestiform tremolite (p = 0.6104). For application and clean-up of talc spiked with 0.005% asbestiform tremolite, 2 of 24 (8.3%) samples were above the LOD for TEM (0.003 f/cc). For application of talc spiked with 0.1% asbestiform tremolite, 21 of 24 (87.5%) were above the LOD for TEM. The corresponding mean PCME asbestos concentrations were 0.016 f/cc for puff and shaker for samples collected in the first 15 min, 0.002 f/cc for puff and 0.004 f/cc for shaker in the second 15 min, and 0.005 f/cc for puff and 0.013 f/cc for shaker for the full 30 min. Mean PCME concentrations for samples collected during clean-up following application of talc spiked with 0.1% asbestiform tremolite were 0.003 f/cc for samples collected in the first 15 min following puff application, 0.005 f/cc for samples collected in the second 15 min following shaker application, and 0 f/cc for the remaining clean-up samples. Using the EPA’s exposure factors, we determined the range of cumulative asbestiform fiber exposures that would result from product use, assuming asbestiform tremolite was present at 0.1%.

Nature of Mineralizing Fluid in Paleoproterozoic Dolomite Hosted Talc Deposits, Cuddapah Basin, India

Abstract Dolomite hosted talc deposits of the Vempalle Formation (VF), Cuddapah basin, Andhra Pradesh produces nearly 6% of total talc demand of India. The strata bound talc zones extending over kilometers along strike have tabular geometry and are concordant with the stratification and primary depositional contacts, though sometimes the talc bodies locally cross-cut the stratification. Field and petrographic evidences suggest that the strata-bound talc deposit, located at the flank of the basin, was formed by replacement of platformal carbonate sequences of the passive margin (stromatolitic dolomite), preserving the primary texture and structure of the host. Lack of anomalous concentrations of V, Fe, Ni, Cr and Co; depletion of Ta, Hf, Zr and Th and Ni, Cu, Pb, Zn in the talc and talc bearing dolomites may be indicative of the absence of magmatic and/or metamorphic source for the mineralization fluid. The igneous intrusions within the Vempalle Formation (VF) – earlier thought to be the source of mineralization fluid – thus are neither coeval with talc mineralization nor they acted as the heat source. Furthermore, depletion of REE, Al3+, K+, Na and Sr in the talc and talc bearing dolomites suggest that the mineralizing fluid was probably evolved from Paleoproterozoic ocean water that was super-saturated with respect to talc and had higher dissolved silica concentration. This evolved fluid source can also explain the supply and sustenance of large volume of water needed for the talcification of the host dolomite.

Mineralogy and Geochemistry of Hydrothermally altered Talcose rocks from Ila Orangun-Oyan areas, part of Southwestern Nigeria

Background/Objectives: Talcose rocks within Precambrian Basement Complex serve as relics of Archean greenstones. alterations associated with polycyclic-orogenies that affected this complex is studied to understand mineralogical and geochemical alterations. Methods: Five fresh samples of talcose rocks were collected during field mapping. These samples were cut into thin sections to reveal modal mineralogy, altered minerals and degree of alteration of such minerals. Mineral phase identification of the talcose rocks was conducted using X-ray Broker D8 ADVANCE diffractometer while whole rock analysis was carried out using Inductively Coupled Plasma Mass Spectrometry. Findings: Lithological relationship revealed from field evidence showed that the talc bodies occurred in close association with micaceous schist. The mineral assemblage of talc, tremolite, actinolite, chlorite and calcite suggest low grade greenschist metamorphic facies from possible hydrothermal alteration. Geochemical results revealed the following range of concentrations; SiO2 42.19-59.03%; Al2O3 1.1 - 11.8%; Fe2O3 7.64-9.56%; MgO 24.47-26.639%; Ni 594-1207ppm; Co 43.2-113.9ppm; Sn 6-41ppm; V 32-75ppm and Zr 1.3-58.7ppm, and these are typical of talcose rocks. Petrogenetic studies suggest a komatiitic origin with a peridotitic komatiite precursor for the talc-chlorite-tremolite schist. Enrichment in LREE, depletion in HREE and a negative Eu anomaly suggest alteration of the parent magma for the talcose rock and plagioclase fractionation. The trends observed for the LILE, HFSE and REE suggest possible contamination or mixing of crustal and mantle materials during the formation of the protolith. Ni and Co concentrations are higher than average crustal values with implication for ultrabasic to basic magma composition for the komatiitic progenitor and also suggestive of possible mineralisation. Conclusion: Mineralogical examination has revealed a talc-chlorite-tremolite composition for the talcose rocks with peridotitic komatiite precursory while geochemical composition supported ultrabasic magmatism similar to those with the Ilesha schist belt.

Understanding Precambrian Komatiite Petrochemistry from talc bodies within the Ilesha Schist belt, Southwestern Nigeria

The nature of parentage of talc bodies from the northern part of Ilesha schist belt was investigated and compared with altered ultramafic – Komatiite. Observations from thin sections revealed altered serpentine with included nodular olivines. Talc, chlorite and tremolite were other minerals present. Geochemical analysis of five (5) rock samples taken from talc bodies outcropped from both sides of the Ifewara Shear Zone (ISZ) revealed magnesia (MgO) > 18% and Al2 O3 /TiO2 values ~ 40. MgO values ranged from 23.01 – 32.79 wt. %. Al2 O3 and TiO2 values averaged 2.34 and 0.04wt. % respectively. Mg# values (87.93 – 90.71) supported ultramafic precursor. Major oxide variation plots against magnesia revealed negative correlation in Al2 O3 TiO2 vs MgO. Co, V, Ni and Cu concentrations were significantly higher than the incompatible elements. Maximum Ni and Co values were 1765.10 ppm and 108.60 ppm respectively. The rare earth element (REE) concentrations showed relative enrichment in light rare earth element (LREE). The values of Gd/Yb(N) ranges from 0.94 – 1.86. The Gd/Yb(N) and Al2 O3 /TiO2 suggested that the precursor to the talc bodies were possible Gorgona group IIItype komatiite. Plot of V vs Ti indicated an Island arc environment for the emplacement of these talc bodies.Keywords: Gorgona-type-Komatiite, Talc-bodies, ISZ, Serpentine, Magnesia

Genesis of giant Early Proterozoic magnesite and related talc deposits in the Mafeng area, Liaoning Province, NE China

This study aims to understand the origin of giant magnesite and talc deposits in the Liaohe Group (Liaoning Province, NE China). Magnesite stromatolites and the composition of fluid inclusions suggest that magnesite or high-Mg calcite precipitated directly from strongly restricted seawater pools with meteoric influx. A primary evaporitic origin is also indicated for parts of the investigated dolomites by comparably heavy δ18O values. Later, intense metasomatic activity led to the formation of a magnesite/dolomite succession with irregular contacts and a lighter isotopic signature of oxygen. A slight shift in δ18O to more positive values was observed for talc-hosting magnesite, which can be explained by the incorporation of isotopically light oxygen into talc. This highlights that the hydrothermal processes that led to talc formation influenced the hosting carbonates as well, which is also documented by a tendency to smaller crystal sizes, a higher whiteness and lower trace element concentrations in samples from locations nearby large talc bodies. Although δ13C is suggested to be less sensitive to hydrothermal activity, comparably light δ13C values were determined for magnesite sinters, as well as for remobilized magnesites. In general, the δ13C signature of the investigated magnesites is lighter than expected for Proterozoic carbonates. A single-stage generation of the giant talc deposit in the study area is suggested based on elemental and isotopic data. Later deformation led to a (iso-chemical) re-location of talc at least once. During this process, irregularly distributed, cloudy/massive talc bodies acted as weak zones and were incorporated into shear bands up to several meters in thickness, which form the actually present, structurally controlled deposit. The original ore type is preserved only in areas with minor deformation. Lamprophyre dykes prove Jurassic volcanism and are clearly younger than the main phase of talc generation. A younger (post-Jurassic?), intense tectonic event is indicated by strongly tectonized dyke material that is re-worked into strike-slip faults and shows siliceous contact zones to the surrounding magnesite. These faults occasionally cross-cut the older, deposit-forming talc shear bands, indicating that the event that led to the deformation of lamprophyre dykes was younger than the main phase of talc re-location. However, this younger event did not lead to a second phase of major talc generation or affect the quality of the initial deposit to a large extent.

Geology of the Fontane talc mineralization (Germanasca valley, Italian Western Alps)

ABSTRACTThe 1:5000 scale Geological Map of the Fontane talc mineralization (FTM) aims to give new information about the origin and geological structure of an important talc mineralization occurring in the axial sector of the Italian Western Alps. The FTM is hosted within a pre-Carboniferous polymetamorphic complex which was deformed and metamorphosed during both Variscan and Alpine orogenesis, and is part of the Dora-Maira continental crust. Field mapping and underground investigations highlight that the talc bodies (i) never crop out but occur at depth along a well-defined lithostratigraphic association between micaschist, marble and gneiss and (ii) were deformed during different Alpine-related deformation phases (i.e. D1, D2 and D3 syn-metamorphic phases and post-metamorphic extensional faulting). The here defined lithostratigraphic and structural characterization of talc bodies, is an input for further research into the geodynamic context of where talc forms and for new mineral exploration outside the mapped area.

Complex structural and fluid flow evolution along the Grenville Front, west Texas

A narrow (∼7 km wide) fold and thrust belt in west Texas that represents the northernmost extent of a Grenville-age collisional belt along the southern margin of Laurentia (Grenville Front), records a complex history of deformation and associated fluid flow. The Streeruwitz thrust that emplaced ca. 1.35 Ga high-grade metamorphic rocks over ca. 1.25 Ga foreland sedimentary and volcanic rocks postdates polyphase deformation in the footwall and is complexly folded into domes and basins. Four phases of tectonism, recording a changing kinematic setting, affected the area and formed: (1) pre-Streeruwitz ductile polyphase folds (F 1 –F 3 ) and associated foliations (S 1 –S 2 ) consistent with northward tectonic transport; (2) dextral oblique-slip, high-angle, west-northwest–trending faults associated with upright vertical sheath folds (F 4 ); (3) Streeruwitz and related subsidiary imbricate thrusts that truncate F 1 –F 4 folds at a high angle and cause localized folding (F 5 ) consistent with north-northeast to northeastward tectonic transport; and (4) complex southeast- and northwest-trending domes and basins (F 6 ) of the thrusts, resulting from continual Grenville-age transpression. Fluids with an evolving chemistry over time were channelized along the thrusts, metasomatically altering the adjacent rocks. Early siliceous fluids caused replacement of mafic dikes and dolostones that preserve F 1 and S 1 and formation of extensive talc bodies with talc aligned axial planar to F 2 , forming the dominant S 2 fabric. Initial thrusting at depth produced mylonites in both footwall (syn-S 2 ) and hanging-wall rocks that were later brecciated in the final stage of thrusting along the Streeruwitz thrust. Further evolution of fluids along the thrusts is recorded in altered rocks adjacent to thrusts, breccias, and veins, starting with silica- and alkali-rich fluids. Lastly, carbonate-rich fluids replaced footwall rocks and cemented breccias in both the hanging wall and footwall. This study documents a previously unrecognized complex structural, metamorphic, and metasomatic history, and fluid evolution in the foreland. This history, coupled with differences from that in the overriding older metamorphic rocks, requires a new kinematic model for the southern margin of Laurentia. In addition, the disparity in deformation timing and kinematic evolution between west Texas and the central Texas Llano uplift requires active subduction in west Texas after collision in central Texas. We propose that collision of a north-verging continental indenter with southern Laurentia initially occurred in the Llano area (ca. 1150–1120 Ma) and that continued subduction along strike caused clockwise rotation of the indenting continent and collision in west Texas (ca. 1060–980 Ma).

Using the geologic setting of talc deposits as an indicator of amphibole asbestos content

This study examined commercial talc deposits in the U.S. and their amphibole-asbestos content. The study found that the talc-forming environment directly influenced the amphibole and amphibole-asbestos content of the talc deposit. Large talc districts in the U.S. have mined hydrothermal talcs that replaced dolostone. Hydrothermal talcs, created by siliceous fluids heated by magmas at depth, consistently lack amphiboles as accessory minerals. In contrast, mineable talc deposits that formed by contact or regional metamorphism consistently contain amphiboles, locally as asbestiform varieties. Examples of contact metamorphic deposits occur in Death Valley, California; these talc-tremolite deposits contain accessory amphibole-asbestos. Talc bodies formed by regional metamorphism always contain amphiboles, which display a variety of compositions and habits, including asbestiform. Some industrial mineral deposits are under scrutiny as potential sources of accessory asbestos minerals. Recognizing consistent relations between the talc-forming environment and amphibole-asbestos content may be used in prioritizing remediation or monitoring of abandoned and active talc mines.

COMPOSITION FEATURES AND INDUSTRIAL APPRALSAL OF THE BABA ODE TALC OCCURRENCE, SOUTH WESTERN NIGERIA

The Baba Ode talc with a preliminary quantitative estimation of 3 million tons, occurs in close association with a mafic complex. This complex is surrounded by a series of compositionally variable gneisses, syenites, phillytes and mica schists, granites and coarse pegmatites all of the Iseyin-Oyan schist belt. This study aims at assessing the petrographic, chemical and physical composition of the talc body in order to appraise its industrial suitability. Two petrographic varieties, a white talcose, and a fibrous light grayish tremolitic variety characterize the body. X- ray and petrographic studies show that mineralogically they comprise mainly of talc, tremolite and chlorite with subordinate quartz and muscovite. Chemical analysis of representative samples using Atomic Absorption Spectrometer (AAS) instrumentation methods show that the tremolitic variety is higher in Si20 (53.97%) and Al203. (1.9%) than in the talcose. Fe (t) as Fe203 (4.35%) and Ca0 (1.7%) content in the two varieties are non-variable. While Mg0 values in the talcose (33.25%) is higher than in the tremolitic type (31.39%). Concentration of Ti02, Mn02, Na0 and P205 for both varieties do not exceed 0.25%. Firing characteristics reveal an average loss on ignition (L.O.I) of 4.21% for the two types. Linear shrinkage (L.S.V) average 1.35% while average water absorption capacity is 4.1%. A flat to gently undulating topographic configuration and easy accessibility enhance the mineability of body. The talc body therefore with some beneficiation will be useful in paper, paint, roofing and ceramic manufacturing. Key words: Talc occurrence, petrographic, chemical, industrial. [Global Jnl Geol. Sci. Vol.1(1) 2003: 63-72]

Quantitative comparison of asbestos and talc bodies in an individual with mixed exposure

Tissue from an individual with a history of exposure to asbestos and other dust was referred for particulate analysis. The digested material was reviewed by light microscopy to establish the numbers of ferruginous bodies per gram of tissue. Typical asbestos bodies were found at levels consistent with occupational exposure. A second type of elongated ferruginous body was formed on a thicker transparent core which suggested the minerals were sheet silicates. The number of ferruginous bodies with nonasbestos cores was over four times the number of asbestos cored ferruginous bodies. Electron microscopy was used to confirm the core composition of both populations and also to establish the levels of uncoated fibers. The nonasbestos ferruginous bodies were predominantly formed on talc.

Mineralogy and origin of the State Line talc deposit, Pennsylvania

The State Line talc deposit, in Lancaster County, Pennsylvania, near the Maryland border, occurs at the boundary between a serpentinite body and surrounding metamorphosed pelitic rocks. Blackwall-type zones are found in the talc body. The zones are composed of variable amounts of tremolite, chlorite, biotite, and dolomite. However, trace element chemistry indicates that the zones are not a product of simple blackwall metasomatic processes. The ratios of Al 2 O 3 /Cr, Zr/Cr, Ti/Cr, and Al 2 O 3 /Ni in the blackwall-type zones are intermediate between the ratios found in the serpentinite and the pelite, supporting the hypothesis that these zones result from the sedimentary mixing of pelitic and serpentinite-bearing material on the sea floor, with later modifying metasomatism.The distribution of tremolite, a contaminant that affects significantly the market value of a talc deposit, is the result of small-scale metasomatic reactions that modified the original layers of serpentinite-bearing and pelitic detritus; and larger scale metasomatism involving silica, water, and carbon dioxide that fixed tremolite as the saturating calcium phase in the proximity of the pelitic country rock, and dolomite in the proximity of the serpentinite.

Hydrothermal alteration haloes and enlarged soil anomalies over concealed talc bodies, southwestern Montana

Anomalous concentrations of talc have been found in residual soil associated with buried and blind talc bodies in southwestern Montana. In order to better understand the intensity and distribution of the residual talc, rock samples obtained by means of drilling have been studied. In general, except for massive talc, the rock is calcitic or dolomitic marble. In the weathering environment, the carbonate is leached away leaving the insoluble material as residual soil. This being the case, the minerals of primary interest are in the acid insoluble portion of the drilling samples. X-ray diffraction analysis shows talc to comprise 50% or more of the acid insoluble residue obtained from the marble. Talc and chlorite occur in some parts of the zone in sufficient quantities to be visually identified in the hand samples. In addition to talc and chlorite, minor amounts of chlorite/smectite and corrensite-type mixed-layer minerals occur randomly. The outer zone shows talc averaging less than 20% of the insoluble. Generally an amount of smectite±vermiculite equal to that of talc is present. Talc and other layer-silicate minerals cannot be identified in hand sample. The alteration zonation appears to be compatible with origin by hydrothermal fluids having decreasing temperature away from the talc zone. In deposits studied, the size of the alteration zones appears to be directly related to the size of the talc body. Because the insoluble minerals end up in the residual soil as a result of weathering and because the analytical procedures for Montana soils involve nonfractionated bulk samples, a large zone of talc-rich residual soil will be found to overlie and surround most buried or blind bodies suggesting a much larger body than actually present. However, such soil zones also offer sizeable targets for exploration.

The use of soil anomalies to locate concealed talc bodies

Residual carbonate-rich collected from a site thought to overlie a talc body were analyzed by X-ray diffraction to determine which of five methods of pre-treatment or calculation is most efficient in showing the positive talc anomaly. A talc distribution map was plotted for each method with the following results: (1) the map of percent talc acid-treated samples showed one large anomaly. (2) The map of percent talc for non-acid-treated samples showed two smaller positive anomalies similar in area of coverage to that obtained for acid treated samples. (3) Intensities corrected for the amount of carbonate, yield a map with anomalies similar to acid treatment. (4 and 5) Data obtained for carbonate-containing samples analyzed for absolute talc intensity (uncorrected for carbonate) or from heat-treated (carbonate corrected) samples were of less value in finding areas of talc concentrations. Consequently, maps obtained by calculating percentage values for talc yield the best results. Acid-treated samples provide the greatest accuracy but take the longest time to prepare; whereas, non-acid-treated samples provide good results at a substantial saving of time.

Petrogenesis and timing of talc formation in the Ruby Range, southwestern Montana

Talc deposits in the Ruby Range, southwestern Montana, have formed in Archean dolomitic marbles that were mineralized during retrograde talcification in the Proterozoic. Calcite-rich marbles contain the assemblage calcite-olivine-phlogopite + or - tremolite, indicating that metamorphism occurred in the upper amphibolite to granulite facies (M 1 ); crystallization of serpentine and chlorite, and dolomitization of the marbles in the greenschist facies overprinted the high-grade calc-silicate assemblages (M 2 ); and talc has replaced dolomite and the other greenschist-grade silicate minerals in the latest stage of recrystallization which resulted in the formation of the main talc bodies (M 3 ). Structural control of the talc formation is suggested by discontinuous occurrences of talc bodies along layer-parallel fractures. Preservation of relict textures indicates that the talc formed during constant volume replacement. Geochemical analyses and mass balance calculations demonstrate that introduction of large quantities of Si and Mg and removal of Ca is required to maintain constant volume. Model reactions indicate that infiltration of a minimum of 4.8 x 10 5 1 of water is needed to convert a cubic meter of the average high-grade marble to talc (volumetric water/rock ratio > 600). The infiltration mechanism is consistent with the observation that no isobaric univariant mineral assemblages were present to buffer the composition of the metamorphic fluids. Estimates of the maximum conditions of talc formation of 2 kbars and 400 degrees C are based on field observations and heterogeneous phase equilibria; it is probable that the talc actually formed at much lower temperatures and pressures, possibly in a near-surface hot spring deposit. Regional geologic relations indicate that the talc mineralization occurred during the middle Proterozoic.

Mineralogy and geochemical dispersion in tropical residual soils overlying a talc deposit in southwestern Nigeria

Soil profiles overlying a talc deposit and associated amphibolite country rock have been investigated in order to determine the mineralogy and nature of geochemical dispersion, as a potential tool of industrial mineral prospecting in tropical terraines. Results of mineralogical analysis show that in soils overlying the talc body, talc still persists as a major component of the soil, in association with quartz, chlorite, illite and goethite, whereas in the amphibolite soil, most primary minerals have decomposed to kaolinite, quartz and goethite. Chemical variations in the soils are characterized by general enrichment in Fe 2O 3 and Al 2O 3, and depletion in Na 2O, K 2O, CaO, MgO and FeO relative to the parent rocks. Trace-element abundances show inconsistent patterns. While Ni and Co are depleted relative to the parent rocks, Zn and Cu show considerable enhancement. In spite of the intense weathering characteristics of tropical environments, high MgO contents of the soils seem to be the only reliable geochemical indicator of the existence of talc deposits beneath the soil cover. This parameter in conjunction with X-ray diffraction analysis of the soils may constitute an invaluable exploration tool for detecting buried talc deposits.

Expandable layer silicates associated with hydrothermal talc deposits of Murphy, North Carolina

Corrensite and other mixed-layer chlorites occur in the insoluble residues from the Murphy Marble. They are found in an ordered arrangement around one of the eight zones in the Murphy Marble. The envelope, 60 m wide, is centered on the mottled zone in the upper part of the marble formation. The progression of the layer silicates is: vermiculite --> vermiculite-smectite --> smectite --> smectite-chlorite --> corrensite + chlorite --> chlorite. In addition, quartz, plagioclase, and muscovite may occur. The mottled zone appears to have been a conduit of the hydrothermal fluids which have altered the silicates in the marbles; isotopic data supports this hypothesis. The altered carbonate rock is depleted in heavy isotopes. A genetic connection, between the talc bodies and the hydrothermal plumbing system, is indicated by an increase in the amount of expanding and contracting layers in the mixed-layer minerals of the mottled zone near the orebody.--Modified journal abstract.

Mineralogy of residual soils overlying a talc deposit

The residual soil overlying a talc deposit, which occurs as a lens between gneiss and serpentinite in Lancaster County, Pennsylvania, contains talc in all size fractions studied (10 μm to less than 2 μm) and in unfractionated samples. A study of soil samples, obtained by auger drilling, indicates that small amounts of talc can be detected by X-ray diffraction in samples obtained over a large area when the X-ray samples are prepared so that the clays are well oriented. Randomly oriented X-ray samples, in which the level of detection of talc is much poorer, also were successfully used to determine the presence of the talc body by means of quantitative measurements. In addition, the latter procedure was found to be superior in determining the actual size and location of the ore body. It is proposed that such procedures might be used in exploration for similar talc deposits.

The mineralogy and origin of the talc deposits near Winterboro, Alabama

The north and south talc bodies near Winterboro, Alabama, are associated with Cambrian dolomite. The north body lies like a blanket in residual clay which overlies the dolomite bedrock, and the lense-shaped south body is oriented along a fracture in the dolomite with a strike of N 65 degrees W and a dip of 43 degrees NE. The nature and distribution of insoluble residues in the dolomite as well as textural and field evidence suggest that hydrothermal solutions and metasomatic processes produced talc in and near fractures in the dolomite. These solutions are apparently also responsible for the production of chlorite in the dolomite and in associated shales and sandstones, or chlorite metasomatites, beneath the south body. Weathering exposed the north body and part of the south body and produced brecciation and silicification as well as a residuum of talc and chlorite in the vicinity of the orebodies.Insoluble residues in dolomite obtained from diamond drill cores suggest that a mineralized halo of talc and chlorite extends at least 200 feet from the main orebody, with the talc to chlorite ratio increasing as the talc body is approached. This feature, the presence of talc in the residual soils overlying the dolomite, and the associated chlorite and chlorite metasomatites may be useful in prospecting for Winterboro-type talc deposits.

Use of talc bodies in walltiles

Use of talc bodies in walltiles

A STUDY OF THE EFFECT OF THE SUBSTITUTION OF CALCINED BALL CLAY FOR NONPLASTIC IN PORCELAIN AND TALC BODIES

It has been the purpose of this study to determine the effect of the substitution of calcined ball clay for flint in certain type bodies. Complete data on the physical properties of these bodies has been obtained, including electrical resistivity up to 980°C. A substitution of calcined ball clay for a portion of the talc in a type talc body has also been made.