Method and transferred arc plasma system for production of fine and ultrafine powders

A method for the production of fine and ultrafine powders with a transferred arc plasma system, the method comprising the steps of:

• providing a material to be vaporized or decomposed in a plasma reactor;
• supplying a plasma torch feed gas;
• striking an arc between the material and an electrode to generate a plasma having a temperature sufficiently high to vaporize or decompose the material and form a vapor thereof;
• injecting a diluting gas that is heated to a temperature of at least about 1000 K. into the plasma reactor;
• transporting the vapor by means of the plasma gas and diluting gas into a quench tube wherein the vapor is condensed and powder formation occurs, the transporting step further comprising the steps of:
• indirectly cooling or heating the vapor in a first section of the quench tube to cause particle growth and crystallization in said first section;
• and
• directly cooling in a second section of the quench tube the grown particles passing from the first section;
• and
• collecting the cooled particles in a collection unit,
• wherein the collecting step collects at least 0.5 kg/h of particles.

A method for the production of a fine powder of a metal with a transferred arc plasma system, the method comprising the steps of:

• continuously providing a metal to be vaporized in a crucible inside a plasma reactor;
• supplying a plasma torch feed gas;
• striking an arc between the metal and a non-consumable electrode in a straight polarity configuration to generate a plasma having a temperature sufficiently high to vaporize the metal and form a vapor thereof;
• injecting a diluting gas that is heated to a temperature of at least 1000 K, into the plasma reactor, the diluting gas being port at a location that is physically separated from the plasma torch feed gas;
• transporting the vapor by means of the plasma gas and the diluting gas into a quench tube wherein the vapor is condensed and powder formation occurs, the quench tube comprising:
• a first section comprising an elongated tubular body for indirectly cooling or heating the vapor therein, the vapor passing through the inside of the body, and
• a second section coupled to the first section for directly cooling powder particles passing from the first section by injecting a cooling fluid directly into the second section;
• and
• collecting the powder particles in a collection unit.

A method for the production of a fine powder of a metal with a transferred arc plasma system, the method comprising the steps of:

• continuously providing a metal to be vaporized in a crucible inside a plasma reactor;
• supplying a plasma torch feed gas to the plasma reactor;
• striking an arc between the metal and a non-consumable electrode in a straight polarity configuration to generate a plasma having a temperature sufficiently high to vaporize the metal and form a vapor thereof;
• injecting a diluting gas that is heated to a temperature of at least 1000 K, into the plasma reactor the diluting gag being injected at a port that is physically separated from the plasma torch feed gas;
• transporting the vapor by means of the plasma gas and the diluting gas into a quench tube wherein the vapor is condensed and powder formation occurs;
• the method further comprising the steps of (i) indirectly cooling or heating the vapor in a first section of the quench tube to cause particle growth and crystallization in the first section, and (ii) directly cooling the grown particles in a second section of the quench tube by injecting a cooling fluid directly into the second section;
• and
• collecting the cooled particles in a collection unit.