subject: Detailed And Professional News Of Alumina Ball [print this page] This invention relates to friable particles having the following combination of properties: an alumina ball content of at least about 98.5%, a surface area of less than about 1 m 2 /g, an attrition resistance as shown by a weight loss of less than about 0.30 weight % per hour, a particle size of about 30 to 110 microns, a tap density of less than about 1.9 g/cc, a generally spherical shape, and sufficient porosity to hold catalytic metals. The unique combination of properties makes these particles suitable for use as fluid bed catalyst carriers, especially for fluid bed reactors operated at temperatures of above about 800 C. in the presence of steam. This invention further relates to processes for producing particles having this combination of properties.
Essentially spherical particles are disclosed of at least 98.5% alumina ball having a surface area less than about 1 m2 /g, an attrition resistance of less than about 0.3 weight percent/hour in an air jet attrition test, a particle size of about 30 to about 110 microns, a tap density of about 1.3 to about 1.9 g/cc, and sufficient porosity to hold catalytic metals in conventional catalytic amounts. The alumina ball particles are especially suited for use as fluid bed catalyst carriers for use in environments involving the presence of steam, particularly at high temperatures.
A process for producing friable particles having an alumina ball content of at least about 99.5 weight percent, a surface area of less than about 1 m2 /g, an attrition resistance of less than about 0.3 weight percent per hour when tested in an air jet apparatus, a particle size ranging from about 30 to about 110 microns, a tap density of about 1.3 to about 1.9 g/cc, a generally spherical shape, and sufficient porosity to hold catalytic quantities of catalytic metals, said process comprising (i) heating hydrated alumina particles having a particle size of about 35 to about 150 microns to remove at least about 90 weight percent of the bound water and to convert the hydrate to at least gamma alumina ball and (ii) entraining the particles in a carrier gas and passing them through a high temperature zone of a plasma spray at a temperature sufficient to at least partially melt the particles and to cause them to have the properties.
