Apparatus for on-line detection of magnetic resonance signals from a target material in a mineral slurry

An apparatus for on-line detection of magnetic resonance signals from a target material in a mineral slurry, the apparatus comprising:

• an electrically conductive housing;
• an electrically non-conducting (ENC) pipe to enable throughput of a mineral slurry, the ENC pipe configured to pass through the electrically conductive housing;
• one or more primary coils configured to encircle a section of the ENC pipe within the housing, each primary coil defining a measurement zone;
• a capacitor unit coupled to a terminal of each respective primary coil, where a value of each capacitor unit value is selectable so that a primary coil series resonance is formed close to a value of a magnetic resonance frequency of the target material;
• an RF transmitter operable to transmit a signal to one or more drive coil electrical networks, where an operating frequency of the RF transmitter is set approximately equal to the magnetic resonance frequency of the target material;
• one or more drive coils each having an associated drive coil electrical network, where the number of drive coils equals the number of primary coils, and where each drive coil and associated drive coil electrical network is positioned relative to a single primary coil to magnetically couple said drive coil to said primary coil;
• an impedance monitor coupled to each drive coil electrical network and operable to measure a complex input impedance of said drive coil electrical network;
• and
• an RF receiver adapted to receive from each drive coil electrical network, magnetic resonance signals from the target material, the RF receiver forming an output signal of detected signals.