Heat resistant and light weight container for materials to be ashed, and process for manufacture thereof

A container for an ashable material to be ashed by heating in an ashing furnace, which container is suitable for use in an ashing furnace that is heated by microwave radiation of microwave absorptive elements thereof, which is heat resistant, walled, light in weight, microwave transmissive and porous and is made of a material of construction which is a non-woven thin sheet of quartz microfibers, which are held in walled container form, which sheet is of a thickness in the range of 0.2 to 0.7 mm., of such porosity that the pressure drop across it is 1 to 5 mm. of mercury at 5 cm./sec. face velocity of air, resistant to high temperatures, up to 500.degree. C., retentive of micron size particles, transmissive of microwave radiation and of a weight in the range of 50 to 200 g./m..sup.2, which thin sheet of quartz microfibers has been heat cured to walled container form.

A process for manufacturing a container that is suitable for use as a container for ashable material to be ashed by heat in a furnace in analytical operations, which container is heat resistant during such ashing operations in which it is heated to a temperature up to 500.degree. C., light in weight, porous and includes integral bottom and side wall portions made of quartz microfibers which are held together in walled and bottomed container form, which comprises shaping quartz microfibers to bottomed and side walled container form while such fibers are wet with water, heating such quartz fibers to an elevated temperature to drive off the water and cure or sinter the fibers together, and cooling the container to room temperature, to form the form retaining, light weight, side walled and bottomed, heat resistant container.

A process for manufacturing a container that is suitable for use as a container for ashable material to be ashed by heat from microwave radiation of microwave absorptive elements in an ashing furnace, which comprises shaping a light weight, microwave transmissive and porous sheet of quartz microfibers, which contains 2 to 10% of borosilicate glass microfibers and is of a thickness in the range of 0.2 to 0.7 mm., of such porosity that the pressure drop across it is 1 to 5 mm. of mercury at 5 cm./sec. face velocity of air, resistant to high temperature, up to 500.degree. C., retentive of micron size particles, transmissive of microwave radiation and of a weight in the range of 50 to 200 g./m..sup.2, to container form, wetting such sheet with water before heating the sheet in container form, heating the formed container to a temperature in the range of 500.degree. to 1,200.degree. C. for 1 to 20 minutes, and cooling the container to room temperature in room temperature air, whereby a form retaining ashing container results.