STUDIES ON REFRACTORY CEMENTS AND MORTARS, III

Abstract

The authors, in continuing the previous studies on refractory cementing materials (This Journal, 1936, 44, 441; 1937, 45, 219), communicate in the present report the results of further comparative tests of refractory cements on the market and some samples prepared in the laboratory. The following is the brief abstract from the original Japanese communication.(1) The refractoriness of six samples of refractory cements on the market was determined by the Seger's cone method. The samples were classified in three groups, (a) Samples of high alumina content have high degree of refractoriness (1690-1700°C, SK 31-32), (b) Samples of high silica and low alumina contents have low refractoriness (1270-1390°C, SK 9-13), and (c) Samples of nearly equal amounts of silica and alumina have moderate refractoriness (1470-1540°C, SK 16-20).(2) The slag corrosion actions of several samples of slags, ashes, glasses, etc. on refractory cements were tested as following. The sample of basic blast-furnace slag, copper refinery slag, coal ash and window glass were powdered and mixed with refractory cement in the proportion of 10:90, 20:80 and 30:70, and these mixed powders were put to test their refractoriness by the Seger's cone method as above adopted.(3) All results of several testings already reported in these reports I, II and III were usefully adopted to the preparation of various kinds of test samples of new refractory cement. These refractory cements are composed from the following three elements. (I) The first element is the powder of refractory element of high alumina content prepared by crushing natural diaspore clay or electrically molten mass mainly composed from mullite 3Al2O3⋅2SiO2 and corundum Al2O3. (II) The second elemnt is the powder of hydraulic element of high alumina content composed from calcium aluminate CaO⋅Al2O3 or 3CaO⋅5Al2O3 specially synthesized from Al2O3 and CaO or CaCO3. (III) The third element is in the special case used as the plastic element, which is the fine powder of bentonite, talc, etc, These three elements were intimately mixed in proper proportion, I:II:III in weight prportion as 70:30:0-90:10:0 or 80:15:5-80:18:2. These newly prepared refractory cements have good hydraulic property or quick hardening property of large strength at the room temperature.(4) These new refractory cements were prepared in two series of six samples, Series I: No.1-No.3 and Series II: No.4-No.6, were tested on various points for the purpose of comparison to the common samples on the market tested already in the previous raports. The detailed results of these testings were fully reported and discussed in the present report.(5) The present authors are now further studying on various series of new refractory cements prepared under the same principle and using the same elements above explained. The results will be reported in the next communications.