| 摘要 |
1,194,515. Aluminous cements. C. LAFARGE. 27 July, 1968 [31 July. 1967], No. 35335/68. Heading C1H. A refractory aluminous cement consists of Al 2 O 3 38-40%; AlNa 3 F 6 1À5-2À5% Na citrate 0À18-2À5% and a clinker to 100% of which at least 90% of its particles do not exceed 30 Á and contains Al 2 O 3 69-71%; CaO 28- 30%; SiO 2 and Fe 2 O 3 both below 0À3% other constituents and firing losses below 0À5%, the clinker containing CaO.Al 2 O 3 , and CaO.2Al 2 O 3 in equal proportions. The cement is obtained by heating an appropriate mix of Al 2 O 3 and CaCO 3 in a rotary kiln at 1550-1570‹ C., milling the resulting clinker, adding the other three ingredients and again milling. |
