DOCSLIB.ORG

Wollastonite As a New Kind of Natural Material (A Review)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Wollastonite As a New Kind of Natural Material (A Review) Glass and Ceramics Vol. 58, Nos. 9 – 10, 2001 SCIENCE FOR CERAMIC PRODUCTION UDC 549.642.41:666.32/36.002.3(047) WOLLASTONITE AS A NEW KIND OF NATURAL MATERIAL (A REVIEW) N. I. Demidenko,1 L. I. Podzorova,1 V. S. Rozanova,1 V. A. Skorokhodov,1 and V. Ya. Shevchenko1 Translated from Steklo i Keramika, No. 9, pp. 15 – 17, September, 2001. An analysis of literature and patent data on the problem of producing and using wollastonite and wollasto- nite-based materials is carried out; the results of studying the properties of heat-insulating articles produced by the vacuum pumping technology are summarized. The theoretical possibility of using natural wollastonite as a material for the production of heat-insulating articles is demonstrated. Wollastonite is an extremely interesting but little studied synthesis of pigments applied as underglaze paints to majo- material. Due to its set of valuable, sometimes unique pro- lica products [3]. Its use in the production of high-quality perties, especially the low thermal conductivity, it is indis- glazes for porcelain ensures good spreadability of glaze, pensable in many instances, for example, in production of luster, and color. heat-insulating ceramics, such as foundry lining and packing A specific feature of natural wollastonite is the fact that in the metallurgy and automobile industry. wollastonite articles do not undergo significant volume Natural wollastonite in encountered in the form of a mi- changes in the course of their manufacture. Wollastonite is neral based on calcium silicate (CaSiO3 ). added to ceramic mixtures in making facing tiles [1]. Its use The largest world producer and consumer of natural contributes to a decrease in the TCLE, linear shrinkage, and wollastonite is the USA [1]. There are a few wollastonite de- water absorption and ensures high thermal resistance and a posits in our country (in Siberia, the Ural Region, and constant volume in articles. Karelia), but this mineral is not currently mined; therefore, The quality of wollastonite and wollastonite-based mate- concentrated natural wollastonite has to be imported from rials improve when its concentration is high. Finland, USA, India, or the CIS countries. The demand for wollastonite is currently expanding, in Since 1997, the Trans-Resurs JSC is the only supplier of particular, with respect to metallurgy companies working for natural wollastonite from the Verkhne-Bodamskoe deposit in aircraft, and in the context of the problem of replacing asbes- Kazakhstan to the Russian mineral market [2]. Wollastonite tos, which is hazardous to heath [4, 5]. from the Bosaginskoe deposit in Kazakhstan is known as The most objective parameter characterizing hazard rep- well and is in demand. As for imported varieties of natural resented by various chemicals is the value of their maximum wollastonite, the especially pure wollastonite from India permissible concentration (MPC) in air. Below are compara- merits a special note, since it surpasses the Bosaginskoe vari- tives MPC values for the compounds used in making heat-in- ety in its content of the main components and in several phy- sulating materials [6, 7]. sicomechanical properties. Wollastonite has a fibrous structure in the form of nee- Material MPC, mg/m3 dle-shaped crystals, which makes it possible to use it as a Natural and synthesized asbestos, filler in paints [1]. The needle-shaped wollastonite crystals as well as mixed asbestos-rock dust facilitate a better and more homogenous distribution of containing not more than 10% asbestos .........2 paints over the surface of an article. It is used as well in the Glass and mineral fiber (as a typical representative of wollastonite) .......4 1 Institute of Physicochemical Problems of Ceramic Materials at the Rus- sian Academy of Sciences, Moscow, Russia; All-Russia Institute of Light- Comparing the MPC values for dust of asbestos, asbes- weight Alloys, Moscow, Russia. tos-bearing materials, and wollastonite, it can be seen that 308 0361-7610/01/0910-0308$25.00 © 2001 Plenum Publishing Corporation Wollastonite As a New Kind of Natural Material 309 wollastonite is a relatively safe material: its MPC is two CaCO3, vein quartz SiO2, rice husk ash, and diatomite. The times higher than that of asbestos and asbestos-bearing mixture contained 20% calcium or sodium plagioclase and materials. some other components, as well as mineralizing agents (3% As for wollastonite, the U.S. National Labor Safety Insti- CaF2 or AlPO4 ). The materials were crushed to a particle tute has carried out an epidemiological research of the mi- size less than 10 mm, the samples were compressed at a pres- ners employed at the Wilsborough mine in order to clarify sure of 100 MPa, and the sintering temperature was deter- the effect of this material on their health. The investigation mined. The largest yield of b-CaSiO3 was obtained in using established that wollastonite is virtually safe with respect to mineralizing additives. its effect on health [1]. Wollastonite is known as an additive affecting the me- There is a known method for producing calcium silicate chanical properties of high-temperature ceramics [11]. Intro- from a suspension containing diatomite, lime, and water by duction of up to 14% wollastonite to zircon mixtures made it hydrothermal synthesis under heating and elevated pressure to possible to lower their sintering temperature to 1280°C (U.S. Patent No. 4647499). The filling agents in making (whereas pure zircon sintered at 1600°C). Furthermore, the heat-insulating products are inorganic compounds: calcium additive improved the mechanical properties of the material. carbonate; iron and zirconium oxides; silicon nitride or car- The effect of synthesized wollastonite on the microstruc- bide. The resulting product has thermal conductivity ture and properties of porcelain has been investigated [12]. It 0.054 W/(m × K) at temperature 100°C and 0.108 W/(m × K) is established that synthesized wollastonite has a high degree at 600°C. The bending strength at temperature 600°C is of crystallization. An increase in the wollastonite content in 0.5 MPa. porcelain mixture intensifies the sintering process, since it is The Osaka Packing Company (Japan) has patented a an intense flux that stimulates porcelain formation, thus low- method for making a lightweight material of calcium silicate ering the firing temperature by 50 – 80°C and reducing the (Japan Patent Application No. 63-19468). A suspension is firing duration. prepared of silicic acid, calcium hydroxide, a compound The study in [13] considers the Kalotermeks refractories based on amorphous carbon, and water in a quantity 5 times (A, B, XP) based on CaSiO3, which were produced in greater than the solid component. The solid carbon com- Czechoslovakia. Their average density is 230 – 260 kg/m3, pound comprises 7 – 50 parts of the solid component. As a bending strength 0.2 – 0.5 MPa, and thermal conductivity consequence of hydrothermal reaction, zonotrite crystals and 0.087 – 0.2 W/(m × K). The Kalotermeks refractories were amorphous carbon are synthesized. After molding, drying, used in the Czech Republic and Slovakia as lining for elec- and firing, a material based on calcium silicate and amor- tric furnaces and high-temperature heaters in melting and phous carbon is formed. The company also suggested a thermal furnaces. method for making articles of CaSiO3 with a metallic powder Wollastonite is also used in foaming compositions, additive (Japan Patent No. 63-23148). which contain water-soluble silicate of an alkaline metal, a The Tokiyama Soda Company (Japan) has developed a foaming agent, monticellite, halenite, dolomite, and mervinite material under the brand Florit, which is intended for produc- powders, and water (Japan Patent Application No. 63-24954). ing porous ceramics [8]. The pore formation in ceramics is The Japanese researchers proposed a method for producing determined by the high fire shrinkage of calcium silicate. articles by hydrothermal synthesis of wollastonite from The material absorbs oil and water well and is easily mold- silicic acid, lime, and water with resin and latex additives able. The specific surface area of the powders is up to in the amount of 20 – 35 parts (Japan Patent Application 450 m2/g, the apparent density 0.08 – 0.22 g/cm3, the calci- No. 46137). nation loss up to 10%, and they contain up to 90% SiO2 and Introduction of up to 15% wollastonite in a mixture of up to 27% CaO. There also exists a method for making as- plastic and nonplastic clays improves the thermomechanical bestos-free heat-resistant material based on calcium silicate properties of articles made of this mixture: it decreases the (Gr. Britain Patent No. 2085044). The material contains fire shrinkage and the TCLE and increases the mechanical wollastonite as the filling agent, and a lime-siliceous com- strength and thermal resistance [14]. pound serves as the binding agent. The material after mold- It is known [15] that the introduction of up to 10% ZrO2 ing is subjected to autoclave treatment under a pressure of and CaO additive in the composite material based on over 0.6 MPa and drying at a temperature above 1000°C. ZrO2 – CaO prevents the volume variations in ZrO2, which It is known that wollastonite ceramics can be synthesized contributes to the strengthening of the material. on the basis of wollastonite material from mica deposits [9]. Japanese researchers have established that addition of The mixture also contains clay and quartz sand. It is deter- aluminum powder to a lime-siliceous mixture containing mined that the samples sinter at 1140 – 1190°C. The bending Portland cement makes it possible by autoclave treatment to strength of the resulting ceramics is 160 – 180 MPa. produce a relatively strong lightweight material capable of Another research considered the sintering and crystalli- withstanding temperatures about 750°C for a long time (Ja- zation of wollastonite synthesized from natural Taiwanese pan Patent Application Nos.
Load more

Recommended publications
  • Wollastonite–A Versatile Industrial Mineral
    Industrial Minerals of the United States Wollastonite–A Versatile Industrial Mineral What is Wollastonite? Wollastonite is a chemically simple mineral named in honor of English mineralogist and chemist Sir W.H. Wollaston (1766–1828). It is composed of calcium (Ca) and silicon and oxygen (SiO2, silica) with the chemical formula CaSiO3. Although much wollastonite is relatively pure CaSiO3, it can contain some iron, magnesium, (Above and right) Hand specimens of manganese, aluminum, potassium, wollastonite showing acicular crystal clusters. sodium, or strontium substituting for calcium in the mineral structure. Pure wollastonite is bright white; the geologic conditions during formation What Makes Wollastonite and host rock composition. The type and amount of impurities can Useful? produce gray, cream, brown, pale- Lewis Deposit, mined by NYCO green, or red colors. Minerals, Inc., in the Adirondack Wollastonite has several physical Mountains in Essex County, was properties that make it useful as an formed by the recrystallization of industrial mineral: Geology of U.S. Precambrian carbonate rocks inter- Wollastonite Deposits layered with high-grade metamor- ∑ Wollastonite is largely inert, phic rocks. Nearby reserves are although it will dissolve in concen- Wollastonite is formed by two contained in the Oak Hill and trated hydrochloric acid. It will not processes. The first occurs when Deerhead deposits. The ore bodies react with other components of silica and limestone are raised to a consist of the minerals wollastonite, manufactured products either during temperature of 400°–450°C, either garnet, and diopside with as much as or after the manufacturing process. because of deep burial (regional 60 percent of the bodies being ∑ During crushing, wollastonite metamorphism) or by being baked wollastonite.
    [Show full text]
  • Wollastonite
    Strictly private and confidential Wollastonite A versatile mineral which can support sustainable farming 07 June 2019 Business Risk Analysis – Visionary Execution Strictly private and confidential 2 Disclaimer & Forward-Looking Statements Cautionary Statement on Forward-Looking Information & Statements: This presentation contains certain forward-looking information and statements which may not be based on fact, including without limitation, statements regarding the Company’s expectations in respect of its future financial position, business strategy, future exploration and production, mineral resource potential, exploration drilling, permitting, access to capital, events or developments that the Company expects to take place in the future. All statements, other than statements of historical facts, are forward-looking information and statements. The words “believe”, “expect”, “anticipate”, “contemplate”, “target”, “plan”, “intends”, “continue”, “budget”, “estimate”, “may”, “will”, “aim”, “goal” and similar expressions identify forward-looking information and statements. In addition to the forward-looking information and statements noted above, this presentation includes those that relate to: the expected results of exploration activities; the estimation of mineral resources; the ability to identify new mineral resources and convert mineral resources into mineral reserves; ability to raise additional capital and complete future financings; capital expenditures and costs, including forecasted costs; the ability of the Company to comply with
    [Show full text]
  • The Conversion of Wollastonite to Caco3 Considering Its Use for CCS Application As Cementitious Material
    applied sciences Article The Conversion of Wollastonite to CaCO3 Considering Its Use for CCS Application as Cementitious Material Kristoff Svensson *, Andreas Neumann, Flora Feitosa Menezes, Christof Lempp and Herbert Pöllmann Institute for Geosciences and Geography, Martin-Luther-University of Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle (Saale), Germany; [email protected] (A.N.); fl[email protected] (F.F.M.); [email protected] (C.L.); [email protected] (H.P.) * Correspondence: [email protected]; Tel.: +49-345-55-26138 Received: 21 December 2017; Accepted: 8 February 2018; Published: 20 February 2018 Featured Application: Building materials and CCS. Abstract: The reaction of wollastonite (CaSiO3) with CO2 in the presence of aqueous solutions (H2O) and varied temperature conditions (296 K, 323 K, and 333 K) was investigated. The educts (CaSiO3) and the products (CaCO3 and SiO2) were analyzed by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and differential scanning calorimetry with thermogravimetry coupled with a mass spectrometer and infrared spectrometer (DSC-TG/MS/IR). The reaction rate increased significantly at higher temperatures and seemed less dependent on applied pressure. It could be shown that under the defined conditions wollastonite can be applied as a cementitious material for sealing wells considering CCS applications, because after 24 h the degree of conversion from CaSiO3 to CaCO3 at 333 K was very high (>90%). As anticipated, the most likely application of wollastonite as a cementitious material in CCS would be for sealing the well after injection of CO2 in the reservoir.
    [Show full text]
  • Experimental Study of Mineral Carbonation of Wollastonite For
    DEGREE PROJECT IN TECHNOLOGY, FIRST CYCLE, 15 CREDITS STOCKHOLM, SWEDEN 2019 Experimental Study of Mineral Carbonation of Wollastonite for Increased CO2 Uptake DINA BABIKER MATILDA AHLSTRAND KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT TRITA TRITA-ABE-MBT-19533 www.kth.se Abstract The cement and concrete industry stand for approximately 8% of the global CO2 emissions. The demand of concrete and cement is expected to increase rapidly with the growing world population and increased urbanization. This makes it of the utmost importance for the industry to try to mitigate its emissions. One way to reduce the industry’s environmental impact is by mineral carbonation curing through which CO2 can be sequestered in the concrete. This investigation studied the CO2 uptake of wollastonite (CaSiO3) which can be used for mineral carbonation. The CO2 uptake of different brands of wollastonite powders for different temperatures, pressures and water to solid ratios were tested through carbonation, and the samples were then analyzed through XRD, SEM and particle size analysis. The results showed large differences in CO2 uptake between the brands of wollastonite powders. They also indicate that lower temperatures lead to higher CO2 uptake but also possibly slow down the reaction rate and that higher CO2 pressures seem to increase CO2 uptake though the effect is small. There was significant variation of the effects of the water to solid ratios on CO2 uptake between the tested brands. The morphology of the powders also seemed to be of little relevance as an amorphous and crystalline powder were the two best performing powders, similarly particle size is not indicated by the result to have a large effect on CO2 uptake, though further studies are required to fully determine the effect of the morphology and particle size.
    [Show full text]
  • Wollastonite Casio3 C 2001 Mineral Data Publishing, Version 1.2 ° Crystal Data: Monoclinic Or Triclinic
    Wollastonite CaSiO3 c 2001 Mineral Data Publishing, version 1.2 ° Crystal Data: Monoclinic or triclinic. Point Group: 2=m or 1: Crystals tabular 100 k f g or 001 , or short to long prismatic, to 20 cm. Commonly cleavable, parallel ¯brous, or compact, f g massive. Twinning: Common; twin axis [010], composition plane 100 . f g Physical Properties: Cleavage: 100 perfect; 001 and 102 , good; (100) (001) = f g f g f g ^ 84.5±. Fracture: Uneven. Tenacity: Brittle. Hardness = 4.5{5. D(meas.) = 2.86{3.09 D(calc.) = 2.90 May exhibit yellow catholuminescence. Optical Properties: Transparent to translucent. Color: White, colorless, brown, red, yellow, pale green; colorless in thin section. Streak: White. Luster: Vitreous, pearly on cleavage. Optical Class: Biaxial ({). Orientation: X c = 30 {44 ; Y b = 0 {5 ; Z a = ^ ± ± ^ ± ± ^ 37±{50±. Dispersion: r > v; weak. ® = 1.616{1.640 ¯ = 1.628{1.650 ° = 1.631{1.653 2V(meas.) = 36±{60± Cell Data: Space Group: P 21=a: a = 15.409(3) b = 7.322(1) c = 7.063(1) ¯ = 95:30(2)± Z = 12, or Space Group: P 1: a = 7.94 b = 7.32 c = 7.07 ® = 90±20 ¯ = 95±220 ° = 103±260 Z = 6 X-ray Powder Pattern: Sampo mine, Okayama Prefecture, Japan (1A). 3.314 (100), 3.83 (84), 3.51 (77), 3.086 (58), 2.302 (52), 2.556 (44), 1.759 (35) Chemistry: (1) (2) (1) (2) SiO2 50.82 50.24 CaO 48.16 35.93 Al2O3 0.46 Na2O 0.12 Fe2O3 trace K2O 0.07 + FeO 0.18 5.54 H2O 0.08 0.00 MnO 0.03 8.16 S 0.14 MgO 0.22 0.07 Total 99.68 100.54 (1) Remonmaki, Finland; corresponds to (Ca1:01Mg0:01)§=1:02Si0:99O3: (2) North mine, Broken Hill, New South Wales, Australia; corresponds to (Ca0:76Mn0:14Fe0:09)§=0:99(Si1:00Al0:01)§=1:01O3: Polymorphism & Series: 1A, 2M, 3A, 4A, 5A, 7A polytypes.
    [Show full text]
  • Minerals Found in Michigan Listed by County
    Michigan Minerals Listed by Mineral Name Based on MI DEQ GSD Bulletin 6 “Mineralogy of Michigan” Actinolite, Dickinson, Gogebic, Gratiot, and Anthonyite, Houghton County Marquette counties Anthophyllite, Dickinson, and Marquette counties Aegirinaugite, Marquette County Antigorite, Dickinson, and Marquette counties Aegirine, Marquette County Apatite, Baraga, Dickinson, Houghton, Iron, Albite, Dickinson, Gratiot, Houghton, Keweenaw, Kalkaska, Keweenaw, Marquette, and Monroe and Marquette counties counties Algodonite, Baraga, Houghton, Keweenaw, and Aphrosiderite, Gogebic, Iron, and Marquette Ontonagon counties counties Allanite, Gogebic, Iron, and Marquette counties Apophyllite, Houghton, and Keweenaw counties Almandite, Dickinson, Keweenaw, and Marquette Aragonite, Gogebic, Iron, Jackson, Marquette, and counties Monroe counties Alunite, Iron County Arsenopyrite, Marquette, and Menominee counties Analcite, Houghton, Keweenaw, and Ontonagon counties Atacamite, Houghton, Keweenaw, and Ontonagon counties Anatase, Gratiot, Houghton, Keweenaw, Marquette, and Ontonagon counties Augite, Dickinson, Genesee, Gratiot, Houghton, Iron, Keweenaw, Marquette, and Ontonagon counties Andalusite, Iron, and Marquette counties Awarurite, Marquette County Andesine, Keweenaw County Axinite, Gogebic, and Marquette counties Andradite, Dickinson County Azurite, Dickinson, Keweenaw, Marquette, and Anglesite, Marquette County Ontonagon counties Anhydrite, Bay, Berrien, Gratiot, Houghton, Babingtonite, Keweenaw County Isabella, Kalamazoo, Kent, Keweenaw, Macomb, Manistee,
    [Show full text]
  • Wollastonite
    WOLLASTONITE W ollastonite was considered by previous W orking Groups in June 1986 (IARC, 1987a) and March 1987 (IARC, 1987b). New data have since become available, and these have been incorporated in the present monograph and taken into consideration in the eva1uation. 1. Exposure Data 1.1 Chernical and physical data 1.1. 1 Nomenclature Chem. Abstr. Serv. Reg. No.: 13983- 1 7-0 Deleted CAS Reg. Nos: 9056-30-8; 57657-07-5 Chem. Abstr. Name: Wollastonite Synonyms: Aedelforsite; gillebächite, okenite; rivaite; schalstein; tabular spar; vilnite (Andrews, 1970) 1.1.2 Structure oftypical minerai CAS formula: CaSiOi Wollastonite was named after W.H. Wollaston, an English chemist and mineralogist. Natural wolIastonite is an acicular (need1e-like) calcium silicate mineraI that occurs in triclinic and monoclinic varieties; these varieties are very difficult to distinguish from one another. When triclinic, the unit celI parameters of wollastonite are as folIows: a = 0.79, b = 0.73 and c = 0.71 nm; a = 90°02', ß = 95°22' and y = 103°26' (Deer et al., 1978; Bauer et al., 1994). lnitially, wollastonite was classified as a pyroxene group mineraI; however, it has since been shown to have a slightly different chain structure. Wollastonite consists of chains of indefinite length containing three Si04 tetrahedra per unit celI. The tetrahedra are joined apex to apex, and one is orientated with an edge parallel to the axis of the chain. These chains are paired; slight offsetting produces the different structural forms of the mineraI. Also within the mineraI structure are calcium atoms, which occur in octa- hedra1 coordination and alternate with layers composed of silica atoms between layers of oxygen atoms (Deer et al., 1978).
    [Show full text]
  • Mineral Carbonation and Industrial Uses of Carbon Dioxide 319 7
    Chapter 7: Mineral carbonation and industrial uses of carbon dioxide 319 7 Mineral carbonation and industrial uses of carbon dioxide Coordinating Lead Author Marco Mazzotti (Italy and Switzerland) Lead Authors Juan Carlos Abanades (Spain), Rodney Allam (United Kingdom), Klaus S. Lackner (United States), Francis Meunier (France), Edward Rubin (United States), Juan Carlos Sanchez (Venezuela), Katsunori Yogo (Japan), Ron Zevenhoven (Netherlands and Finland) Review Editors Baldur Eliasson (Switzerland), R.T.M. Sutamihardja (Indonesia) 320 IPCC Special Report on Carbon dioxide Capture and Storage Contents EXECUTIVE SUMMARY 321 7.3 Industrial uses of carbon dioxide and its emission reduction potential 330 7.1 Introduction 322 7.3.1 Introduction 330 7.3.2 Present industrial uses of carbon dioxide 332 7.2 Mineral carbonation 322 7.3.3 New processes for CO2 abatement 332 7.2.1 Definitions, system boundaries and motivation 322 7.3.4 Assessment of the mitigation potential of CO2 7.2.2 Chemistry of mineral carbonation 323 utilization 333 7.2.3 Sources of metal oxides 324 7.3.5 Future scope 334 7.2.4 Processing 324 7.2.5 Product handling and disposal 328 References 335 7.2.6 Environmental impact 328 7.2.7 Life Cycle Assessment and costs 329 7.2.8 Future scope 330 Chapter 7: Mineral carbonation and industrial uses of carbon dioxide 321 EXECUTIVE SUMMARY This Chapter describes two rather different options for carbon and recycled using external energy sources. The resulting dioxide (CO2) storage: (i) the fixation of CO2 in the form of carbonated solids must be stored at an environmentally suitable inorganic carbonates, also known as ‘mineral carbonation’ or location.
    [Show full text]
  • For the Ceramics Industry
    Performance Minerals for the Ceramics Industry YOUR TRUSTED MINERAL SUPPLIER As the world leader in mineral-based specialty solutions for industrial applications, Imerys transforms a unique range of minerals to deliver performance enhancements that are essential to our customers’ products and manufacturing processes. IMERYS, THE WORLD LEADER IN SPECIALITY MINERALS Imerys delivers high value-added, functional solutions to a diversified Empowering our people: We ensure that health and safety come set of industrial sectors, from processing industries to consumer first by developing and continually improving our health and safety goods. The Group draws on its knowledge of applications, culture and systems to strive for an injury-free workplace. technological expertise and its material science know-how to deliver Developing our human capital by respecting internationally solutions based on the benefits of its mineral resources and recognized human rights and labor practices reflect in our Code of formulations. This contributes essential properties for Business Conduct and Ethics; investing in the talent and skills of our high-performance mineral solutions in the ceramic industry for employees; engaging in constructive social dialogue, and fostering a products such as tableware, sanitaryware, floor tiles, fiberglass, culture of workplace diversity and inclusion based on mutual respect. electrical porcelain or technical ceramics. Caring for our planet: Acting as responsible environmental stewards by assessing environmental risks and continually
    [Show full text]
  • Polysynthetically-Twinned Structures of Enstatite and Wollastonite
    Phys Chem Minerals (1984) 10:217-229 PHYSICS CHEMISTRY [[MIHERALS © Springer-Verlag 1984 Polysynthetically-Twinned Structures of Enstatite and Wollastonite Yoshikazu Ohashi * Department of Geology, University of Pennsylvania, Philadelphia, PA 19104, USA Abstract. Crystal structures of clinoenstatite, orthoenstatite, wollastonite polytypes established the structural relation- wollastonite-lT and wollastonite-2M (parawollastonite) ships between polytypes (Morimoto et al. 1960; Burnham were refined to an R factor 3-4 percent level. Molar vol- 1967; Morimoto and Koto 1969; Trojer 1968), and empha- umes at room temperature are 31.270(15), 31.315(8), sized the close relationship of the structure to the model 39.842(5) and 39.901(10) cm3/MSiO3, in the above-men- produced by applying mathematical operations to the basic tioned order, indicating that one-layer polytypes (clinoen- slab. Stacking sequences of new 3T, 4T, 5T, and 7T wollas- statite and wollastonite-lT) are stable at higher pressures tonite polytypes were determined (Henmi etal. 1978; than two-layer polytypes (orthoenstatite and wollastonite- Henmi et al. 1983), although refinements of atomic coordi- 2M). The polytypic relation of the enstatite polytypes can nates of these longer repeat polytypes were impossible. be described by four twinning operations - b glide [1 to Because of the similarities in chemistries and silicate (110), a glide I[ to (001), twofold screw axis [I to a (of linkages, and the existence of polytypes, enstatite and wol- orthoenstatite) and a twofold screw axis I[ to c. For the lastonite are often compared in parallel. Polytypes of ensta- wollastonite polytypes, twinning operations are twofold tite and wollastonite are, however, different in the way twin- screw axis II to b and a glide [I to (010).
    [Show full text]
  • Occurrence of a Skarn-Type Mineralogy Found in Ciénaga Marbles, Located in the NW Foothills of the Santa Marta Massif (Colombia)
    Occurrence of a skarn-type mineralogy found in Ciénaga Marbles, located in the NW foothills of the Santa Marta Massif (Colombia) Oscar Mauricio Castellanos-Alarcón a, Carlos Alberto Ríos-Reyes b & Luis Carlos Mantilla-Figueroa b a Programa de Geología, Universidad de Pamplona, Pamplona, Colombia, [email protected] b Escuela de Geología, Universidad Industrial de Santander, Bucaramanga, Colombia, [email protected] b Escuela de Geología, Universidad Industrial de Santander, Bucaramanga, Colombia, [email protected] Received: September 3rd, 2014.Received in revised form: August 4th, 2015.Accepted: September 20th, 2015. Abstract The early Cretaceous Ciénaga Marbles that crop out in the NW foothills of the Santa Marta Massif (Colombian Caribbean region) present an epigenetic mineral assemblage (skarn-type), overprinting the metamorphic mineral assemblage previously developed along the regional metamorphic history that affected this unit. The skarn-type mineralogy allows at least three paragenetic contexts to be distinguished, which are represented by the following neoformed minerals: (a) garnet, forsterite, diopside, titanite, wollastonite and calcite (early anhydrous metamorphic stage), (b) actinolite, tremolite, allanite and clinohumite (metasomatic or hydrated stage), and (c) chlorite, serpentine, sepiolite and quartz (late low temperature retrograde stage, probably due to infiltration of descending meteoric waters). The skarn-type mineralogy is observed as alteration halos developed around porphyritic granodiorites emplaced as sills between anisotropy planes related to metamorphic regional foliation of rock that are considered to be the causative bodies of the skarn- type mineralogy. Zircon U-Pb ages obtained from granodioritic bodies yielded an age of 55.5±0.7 Ma (Ypresian, Early Eocene). The formation of the skarn-type mineralogy in the Ciénaga Marbles is temporarily related to the formation and emplacement of hydrated silicate masses that were generated at the beginning of the subduction polarity change (i.e.
    [Show full text]
  • WOLLASTONITE by Robert L
    WOLLASTONITE By Robert L. Virta Domestic survey data were prepared by Christopher H. Lindsay, statistical assistant. Wollastonite, a calcium metasilicate (CaSiO3), has a economy and increased foreign competition in some of the low- theoretical composition of 48.3% calcium oxide and 51.7% value markets. Fording indicated that its subsidiary in New silicon dioxide but may contain trace to minor amounts of York has begun to shift its focus on mid- to high-value markets, aluminum, iron, magnesium, manganese, potassium, and where sales and prices appear to be remaining fairly stable sodium. It occurs as prismatic crystals that break into massive- (Fording, 2001, p. 28). to-acicular fragments. It is usually white but also may be gray, brown, or red depending on its composition. Consumption Wollastonite forms when impure limestones are metamorphosed (subjected to heat and pressure) or silica- In 2001, the use of wollastonite in the United States declined bearing fluids are introduced into calcareous sediments during from that of 2000, again reflecting the state of the U.S. economy metamorphic processes. In both cases, calcite reacts with silica and foreign competition in low-value markets. Sales for to produce wollastonite and carbon dioxide. Wollastonite also ceramic, metallurgy, and in general lower value products can crystallize directly from a magma that has an unusually high probably declined and those for plastics remained unchanged in carbon content, but this is a more rare occurrence. 2001. Deposits of wollastonite have been found in Arizona, In 1999, plastics accounted for an estimated 37% of U.S. California, Idaho, Nevada, New Mexico, New York, and Utah.
    [Show full text]