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The object of this work is to obtain an effective binder as a result of its modification with different salts using the methods of mechanochemistry for further application in corundum refractories. In the present work the influence of mechanochemical treatment and addition of water-soluble aluminium salts (Al2(SO4)3⋅18H2O, Al(NO3)3⋅9H2O, Al(Cl)3⋅6H2O) and zirconium oxychloride ZrOCl2⋅8H2O on the properties of binders and refractories based on aluminum oxide has been investigated. To prepare the binder, ultrafine alpha aluminum oxide was used, to which were added the salts in two ways: 1) alpha aluminum oxide was pretreated in a planetary-centrifugal activator, then it was mixed with aqueous saturated solution of any salt; 2) the mixture of alpha aluminum oxide and salt additives in the form of crystalline hydrates was subjected to joint mechanochemical treatment in the activator. The binder prepared was mixed with fused electrocorundum, then 0.1 N HCl was added to the charge humidity of 10–12%; the samples were formed by vibropressing, dried in air, then they subjected to sintering at the temperature of 1250 °C for 4 h. It has been found that 1) the strength of the samples increases significantly when adding small amounts of zirconium oxychloride or water-soluble aluminum salts to the binder; 2) when preparing the binder, the second way is more preferable, that is, the joint mechanochemical treatment of ultrafine alpha aluminum oxide and additives, as in this case the optimal time of mechanochemical treatment is reduced approximately by 2 times, and, to achieve one and the same strength, smaller amounts of additives are required; the compression strength of modified samples with the density of 2.95–3 g/cm3 after air drying at room temperature has been 10–30 MPa, and after sintering it has been in the range of 108–138 MPa; 3) the use of additives allows to abandon the temporal binders. |
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