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Hydration of magnesia in dolomitic hydrated limes and putties

1937; US government; Volume: 19; Issue: 2 Linguagem: Inglês

10.6028/jres.019.010

2376-5305

L.S. Wells, Kenneth Taylor,

Geological Formations and Processes Exploration

Heat-Qf-solution and ignition-loss methods have been developed for determining the degree of hydration of magnesia in hydrated dolomitic limes and in hydrated dolomitic lime putties.The rate of hydratiQn Qf magnesia in such limes has been studied when the limes were aged as putties at different temperatures, when subjected to steam hydration at variQus temperatures and pressures, and when eXPQsed to different reJative humidities.In the six commercial hydrates studied, 70 to.90 percent Qfl the magnesia was still unhydrated after the customary 1 day of soaking.From 2 to. 4 months were required to hydrate 95 percent of the magnesia when the limes were soaked at rOQm temperature, but the rate Qf hydratiQn was much mQre rapid at higher temperatures. CONTENTSPage I. IntrQductiQn ________________________________ ____ _____________ _ 216 II.MethQds of determining the degree of hydration of magnesia __ _____ _ 216 III.Heats Qf sQlutiQn of CaO, Ca(OHh, CaCOa, MgO, and Mg(OHh ____ 218 IV.Comparison Qf the observed and cll.lculated heats Qf solution Qf hy-drat~d dQIQmitic limes, and the degree Qf hydration of magnesia in these limes __ ________________ __________ ____ ___ ____________ ___ 220 V. Calculations involved in the determination of the degree Qf hydratiQn of magnesia in dQlomitic lime putties by the heat-Qf-solutiQn method ____________________ _________________________________ 223 VI.Rate Qf hydration of magnesia in dolomitic lime putties at rQom temperature ____________________________________________________ 223 VII.Correlation of ignition-loss and heat-of-solution methods for determining the degree Qf hydration of magnesia in dolomitic limes _ _ _ _ 225 1. Calculations involved in the ignition-loss method ___ _________ 226 2. Correlation of heat-of-solution and ignition-loss methods in the case of aged putties ___________________ _________ __ __ ____ 227 3. Correlation of heat-of-solution and ignition-loss methods in the case of steam hydration __ ___ __ ___ ____ _________ ______ ___ 228 VIII.Effect of temperature on the rate of hydration of magnesia in dolomitic limes ____ ____ _____ _________ ___ __ ______________ ___ ___ _______ _ 228 1. Hydration of putties at different temperatures __ ____________ 229 2. Hydration with steam at different temperatures __ ___________ 230 IX.Effect of moisture conditions on the rate of hydration of magnesia in dolomitic hydrated limes ____ ___ _______