A method for determining the solubility of water in silicate melts
A method for determining the solubility of water in silicate melts
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一种测定硅酸盐熔体中水溶解度的方法
DOI：
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发表时间：
1962
期刊：
影响因子：
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通讯作者：
R. H. Jahns
中科院分区：
文献类型：
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作者：
C. Burnham;R. H. Jahns
本文描述的测定水在硅酸盐熔体中的溶解度的方法主要是在给定体系的连续等压T-X H2O剖面中确定液体场和液+气场之间的边界（或投影边界）。它包括在贵金属胶囊中密封已知数量的水和硅酸盐起始材料，在压力容器中熔合和均匀化这些电荷，在指定的实验运行温度和压力下进行平衡，并在规定的时间后淬火。然后检查淬火产品是否有过量水分的证据。在根据临界运行结果确定溶解度值时，对最初被捕获并随后保存在电荷内的含水气泡进行修正，即对熔体中有效不可溶的水进行修正。另一种方法包括在给定系统的连续等压T-X H2O切片中定位液体场和液体+晶体场之间的边界（或投影边界）。这种方法通常产生的结果不太令人满意，主要是由于许多系统的边界坡度适中，以及难以获得所需的精确控制和温度测量。从钠长石玻璃和新墨西哥州哈丁的辉晶岩中提取的熔体中，水的溶解度已通过过量水法测定，作为每次熔体在高达10,000巴的压力和饱和h2o液体温度下的函数。伟晶岩熔体的溶解度值在1000巴和655摄氏度时为4.2 wt %，在2000巴和635摄氏度时为6.6%，在5000巴和650摄氏度时为11.2%，在10,000巴和675摄氏度时为近20%。钠长石熔体的相应值为4.2 wt %（930摄氏度），6.4%（850摄氏度），9.9%（750摄氏度）和16.8%（700摄氏度）。在1000巴的压力下，哈定菱晶岩熔体中水溶解度的温度系数约为-0.2 wt %。在650至850摄氏度的温度范围内，这些研究中获得的溶解度值在高达4500巴的压力下大大低于Goranson根据他的点火失重法对可比材料的报告值。然而，在高于5000巴的压力下，它们比根据Goranson的结果对这些更高压力进行最合理的外推所得的值要高得多。这种差异主要归因于通常被困住并保存在实验电荷中的水泡；这些气泡显然在早期对钠长石和花岗岩熔体的研究中被认为是溶解的水，这可能解释了似乎不正确的位置和形状的压力-溶解度曲线。-
The method described in this paper for determining the solubility of water in silicate melts consists primarily of locating the boundary (or projected boundary) between the field of liquid and the field of liquid+gas in successive isobaric T-X H2O sections for a given system. It involves the sealing of known amounts of water and silicate starting material in noblemetal capsules, the fusing and homogenization of these charges in pressure vessels, equilibration at designated experimental run temperatures and pressures, and quenching after prescribed periods of time. The quenched products are then examined for evidences of excess water. In determining solubility values from the results of critical runs, corrections are made for aqueous bubbles initially trapped and subsequently preserved within the charges, i.e., for water effectively unavailable for solution in the melt. An alternate method involves locating, also in successive isobaric T-X H2O sections for a given system, the boundary (or projected boundary) between the field of liquid and the field of liquid + crystals. This method generally yields results that are less satisfactory, owing chiefly to the moderate slopes of this boundary for many systems and to difficulties in obtaining the precise control and measurements of temperature that are required. The solubility of water in melts derived from albite glass and Harding, New Mexico, pegmatite have been determined by the excess-water method as a function of pressure up to 10,000 bars and at temperatures of the H 2 O-saturated liquidus for each melt. Solubility values for the pegmatite melt are 4.2 wt % at 1000 bars and 655 degrees C., 6.6% at 2000 bars and 635 degrees C., 11.2% at 5000 bars and 650 degrees C., and nearly 20% at 10,000 bars and 675 degrees C. Corresponding values for albite melt are 4.2 wt % (930 degrees C.), 6.4% (850 degrees C.), 9.9% (750 degrees C.), and 16.8% (700 degrees C.). The temperature coefficient of water solubility in Harding pegmatite melt, at a pressure of 1000 bars, is about -0.2 wt % of water per 100 degrees C. rise in temperature through the range 650 degrees to 850 degrees C. The solubility values obtained in these investigations are substantially lower, at pressures up to about 4500 bars, than values reported by Goranson for comparable materials on the basis of his weightloss-on-ignition method. However, they are much higher, at pressures above 5000 bars, than values derived by the most reasonable extrapolations of Goranson's results to these higher pressures. The discrepancies are attributed mainly to aqueous bubbles that normally are trapped and preserved in the experimental charges; these bubbles evidently were reckoned as dissolved water in the earlier work on albite and granite melts, which would account for pressure-solubility curves of seemingly incorrect position and shape. -