Microwave processing of feedstock, such as exfoliating vermiculite and other minerals, and treating contaminated materials

The method of claim 2 applied to exfoliating vermiculite.

The method of any preceding claim in which the microwaves are substantially constrained to stay within a microwave waveguide, and in which the mineral is moved through a microwave applicator attached to the waveguide.

The method of any preceding claim comprising creating a bed of particles of the mineral and applying the microwaves from beneath the bed.

The method of a preceding claim comprising applying at least 1, 5, 10, 20, 30 or more kW of power to the mineral.

The method of any preceding claim in which the bulk mineral is substantially transparent to the microwave frequency used.

The method of any preceding claim in which microwaves are applied at a heating zone and in which dust is extracted at the heating zone by a dust extractor.

The method of any preceding claim in which expanded mineral is produced having a bulk temperature, or the order of, or less than, 150° C. when expanded.

The method of any preceding claim in which expanded mineral is passed directly from an expanding process to a packaging process, without being allowed to stand still for a significant length of time in a cooling process in between.

A method according to any preceding claim comprising having a bed of mineral particles with a generally uniform depth of at least 5 mm, and preferably at least 10 mm or at least 20 mm at the time that microwaves are applied to the particles.

A method according to any preceding claim in which a microwave heating zone extends across substantially the full width of a conveyor belt and the peak microwave energy density and/or cumulative microwave energy experienced by mineral particles as they pass through the heating zone is uniform to within 20%, across the width of the belt.

A method according to any preceding claim performed by a mobile mineral expander, optionally provided in or on a wheeled or tracked vehicle.

The method of any preceding claim where the microwaves have a frequency of about 2.45 GHz, a power of about 15 kW, and a power density of about 1×106 W/m3.

The method of any preceding claim where the microwaves have a frequency of about 2.45 GHz, a power of about 30 kW and a power density of about 1×106 W/m3.

The method of any preceding claim where the microwaves have a frequency of about 900 MHz, a power of about 75-100 kW and a power density of about 1×106 W/m3.

The method of any preceding claim where the microwaves have a frequency of about 900 MHz, a power of about 150 kW and a power density of about 1×106 W/m3.

A microwave particle expander, adapted in use to expand particles using microwaves, comprising a particle-receiving region and a microwave generator, the microwave generator being adapted to generate microwaves at the particle-receiving region having a wavelength capable of exciting water and of producing, in use, a microwave field with a power density of at least 1×106 W/m3.

A method of microwave processing a feedstock comprising applying microwaves from beneath the feedstock.

A microwave treatment apparatus for processing feedstock, the apparatus comprising a treatment region at which feedstock is treated with microwaves, and a microwave delivery port or applicator disposed below the feedstock in the treatment region so as to irradiate the feedstock from below, and preferably which comprises a tunnel microwave applicator.

Use of a microwave applicator beneath a feedstock being processed by microwaves from the applicator in order to make the microwave processing of the feedstock less sensitive to the height or position of the feedstock.

A method of increasing the power density experienced in a feedstock as it is microwaved by a guided waveguide microwave system comprising applying microwaves from beneath the feedstock.