Magnetic field particle confinement in rotary tube furnace

A rotary tube furnace configured to facilitate a chemical reaction between a solid mass and a gas in the furnace, comprising:

• a reaction chamber extending through the furnace, the reaction chamber configured to control ingress and egress of each of the solid mass and the gas in the reaction chamber;
• a passage way configured to supply the solid mass to the reaction chamber;
• a passage way configured to supply the gas to the reaction chamber and circulate the gas through the reaction chamber;
• a heater providing heat to the reaction chamber and configured to control a reaction temperature in the reaction chamber;
• a magnetic field source in proximity to the reaction chamber for generating a magnetic field to one or more reaction zones of the reaction chamber;
• wherein the reaction chamber provides for mixing the solid mass and the gas;
• wherein the solid mass has a particulate form comprising iron-nitride particles having a non-magnetic shell 0.1 to 2.0 nm thick surrounding a magnetic core of the iron- nitride particles.