Document gb67RYoR5gzpdYq4ydDkqVm8L

FILE NAME: RT Vanderbilt (RTV) DATE: 1966 June 1 DOC#: RTV308 DOCUMENT DESCRIPTION: Book Excerpt From RTV Book on Talc FOREW ORD With talc now being recognized as a major component of ceramic whiteware bodies and paint formulations and finding increased use in other industries, we have decided, during this our 50th anniversary year, to put in book form our accumu lated knowledge of this valuable and versatile raw material. ^JEfboogh ppraptf emphasizes Vanderbilt m^^ ie much that is pf general interest tP those who are concerned with the use of N ew lfork State talcs. R. T . VANDERBILT COMPANY, INC. June 1, 1966 The following are registered trademarks, U.S. Patent Office-. AGERITE CAPTAX DARVAN ETH YL ZIMATE METHYL TUADS M ETHYL ZIMATE NYTAL PEERLESS PYRAX SULFADS TRU0D0R V A N Cl D E VANSTAY VEEGUM ZETAX In addition to the above, many calcium and magnesium bearing minerals may be present in small amounts such as calcite, dolomite, magnesite, brucite, apatite, gypsum, phlogopite, pevictase, and hexagonite. Therefore, it is quite evident that these talc deposits may easily contain two or more min erals in greatly varying amounts, depending upon the extent to which the above reactions have taken place. Extreme care in blending is, therefore, essen tial in producing a satisfactory commercial product. Minerai Composition of N Y TA L 100 Early in the development of the "NYTAL" ore body, samples were submitted to the Department of Geology, Columbia University and they reported the following mineral composition: Talc -- Tremolite -- Antigorite -- Magnesite -- Apatite -- Periclase -- Brucite -- Phlogopite-- On the order of one-third On the order of one-third Less than one-third About 5 per cent Minor constituent Minor constituent Minor constituent Minor onstituent At a later date Dolomite, Calcite, Hexagonite, Rhodonite and Gypsum were also found to be present in minor amounts. Engel- states that the zones of commercial talc pinch and swell, and curve in sinuous to complexly folded patterns, as shown in Figure No. 2, but are rudely conformable with adjoining marble layers. The talc zones have a composite strike length of more than five miles, a probable extent down dip in excess of 2,000 feet, and widths of as much as 400 feet. Dips along the talc belts are quite vari able, ranging from the horizontal through the ver tical, but averaging about 45 degrees to the north west. Variations in thickness of the talc belts or of any included zone may be either abrupt or gradual. The belt near Talcville, which contains one pro ducing mine, varies up to 300 feet or more in thickness, averaging perhaps 135 feet thick in the mines. Much of this thickness is commercial talc. A talc belt north of Balmat and southeast and east of Fowler, along which are 2 active mines, varies up to at least 425 feet in thickness, and averages possibly 125 feet, figure 2. In this belt, however, one of several zones of commercial talc 6 to 25 feet thick, or rarely as much as 75 feet thick, are interlayered with impure or discolored non-commercial zones within the belt. Within these two belts are talc reserves sufficient to last several generations at the present rate of production, under resourceful mining methods. IV PR O PER TIES Composition Talc has the theoretical formula of 3Mg0 4SiO,, H.O 31.7% 63.5% 4.8% 1. C h em ical A n a ly se s NYTAL, being a tremolitic talc, has the average chemical analyses as follows: PER CENT NYTAL 99 NYTAL too NYTAL 100HR NYTAL 200 NYTAL 300 NYTAL 400 S10, 5 7.3 MgO 28 .4 CaO 8 .0 F e ,Q . 0 .3 A l .0 0 .6 MnO 0 .3 Na 0 0 .3 Ignition Lo ss 4.8 10 0 .0 5 6 .6 29 .4 7.6 03 0 .5 0 .3 0 .2 5 .1 10 0 .0 5 6 .6 2 9 .2 8.0 0 .3 0 .5 0 .3 -- 5 .1 1 0 0 .0 5 7.5 2 8 .3 7 .2 } l ,5 0 .3 0 .2 50 L00 0 55 .5 29 .0 7 .8 .2 .7 0 .2 -- 5 .6 10 0 .0 5 7.5 2 8 .4 6 .8 } l.6 0 .2 0 .2 5.3 100 0 General Appearance 1. Raw Ore As previously stated there are many types of ore blended to produce the usable commercial talc. The two most distinctive types are a hard, grey, massive type mined for the ceramic industry (Figure No. 3) and the soft, shiny, foliated type mined for the paint industry (Figure No. 4). There is a great difference in the chemical com position of the three major minerals. There is also a vast difference in their physical and pvro-physical properties. Rogers and Kerr1 give the following description of these three minerals when viewed under the microscope. "T A LC occurs in coarse to fine piaty or fibrous aggregates. Talc greatly resembles muscovite (mica) and pvrophyllite. It may be necessary' to make a chemical test in ocdev to prove the identity of talc." '*Tremolite occurs ip long prismatic crystals and columnar to fibrous aggregates. Asbesti- 4 I RAW ORES Figure 3-- Hard Ore Figure 5-- Nytal 99 Figure 4-- Soft Ore form varieties are common. Tremolite has the same genera! appearance as wollastonite." Antigorite occurs in anhedral crystals or aggregates of fibroiamellar structure. It often occurs as pseudomorphs after pyroxene, oli vine, etc." A wide variation in the unctuousness of these minerals has proven to he the physical property hardest to control and one of the most important as it greatly affects both pressing and casting prop erties of ceramic bodies. Figure 6-- Nylal 100 Figure 7-- Nytal 300 5