Method of apparatus for condensing metal vapours using a nozzle and a molten collector
Methods and apparatus for condensing vapour phase compounds or elements, typically metals such as magnesium, obtained by reduction processes.
1. Apparatus for condensing vapour comprising:
a source of gas comprising the vapour, a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
characterized in that the collection medium is a salt flux which has a specific gravity lower than that of the condensed droplets or particles so that in operation the condensed matter settles into a portion of the bath below the condensed liquid.
2. The apparatus of claim 1 , wherein the collection medium is a molten liquid.
3. The apparatus of claim 1 , wherein the collection medium is disposed in a bath.
4. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour, a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
characterised in that means are provided for continuously moving the collection medium through a location at which the beam impinges onto the collection medium, said means comprising a collection medium bath which is provided with a weir over which the liquid collection medium can flow to form a sheet of travelling collection medium on which the beam of condensed vapour impinges, and wherein the nozzle is disposed so as to direct the beam of droplets or particles onto the sheet of liquid falling under gravity from the weir.
5. The apparatus of claim 4 , wherein the nozzle is disposed so as to direct the beam of droplets or particles generally horizontally with respect to the collection medium.
6. The apparatus of claim 4 , wherein means are provided for re-circulating collection medium into the bath after overflowing the weir.
7. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour, a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon, wherein the collection medium is disposed in a bath, and
characterized in that means are provided for circumferentially stirring the collection medium in the bath.
8. The apparatus of claim 7 , wherein the liquid is circulated by a mechanical means.
9. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour and comprising reactive gas and/or a carrier gas,
a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
wherein the nozzle is configured so that on exiting the nozzle the droplets or particles form a first cone and the carrier and/or reactive gases form at least one further cone, the angle of divergence of the first cone being less than an angle of divergence of the second cone, so that the first cone is inside the second cone, and
characterized in that a baffle means is provided at a location so that it is disposed around the first cone and inside the second cone so as to provide a physical barrier which helps isolate the carrier and reactive gases from the condensed droplets or particles which pass through the baffle means into the collection medium.
10. The apparatus of claim 9 , wherein the baffle means is disposed around the location at which the beam of condensed particles or droplets impinges the collection medium.
11. The apparatus of claim 9 , wherein the baffle means comprises an axially elongate conduit, the walls of which provide separation of the first cone from the second cone.
12. The apparatus of claim 9 , wherein the baffle means is surrounded by a shoulder region which covers at least a portion, or all, of the remaining surface of collection medium.
13. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour and comprising reactive gas and/or a carrier gas,
a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
characterized in that the nozzle is configured and/or oriented so that the beam of droplets or particles impinges onto the collection medium at an oblique angle with respect to the medium surface.
14. The apparatus of claim 13 , wherein the collection medium is disposed in a bath and the obliquely oriented beam impinges onto the collection medium at a location radially spaced apart from a central rotational axis of medium in the bath, so that the momentum thereby transferred to the collection medium assists or cause circumferential flow of the collection medium in the bath.
15. The apparatus of claim 1 , wherein the nozzle is symmetric about a longitudinal rotational axis.
16. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour and comprising reactive gas and/or a carrier gas,
a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber,
and a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
characterized in that the nozzle is elongate in a transverse direction so that the beam of droplets or particles is provided in a generally planar or wedge-shaped form and so that the beam impinges onto the collection medium along an elongate contact region.
17. An apparatus for condensing vapour comprising:
a source of gas comprising the vapour and comprising reactive gas and/or a carrier gas,
a condensing chamber fed from the vapour source by a nozzle which has an upstream converging configuration and a downstream diverging configuration so that vapour entering the nozzle accelerates into the nozzle and expands and cools on exiting the nozzle thereby inducing the vapour to condense to form a beam of liquid droplets or solid particles in the condensing chamber, and
a liquid collection medium for the liquid droplets or particles, the collection medium having an exposed surface portion which is disposed so as to permit a beam of droplets or particles exiting the nozzle to impinge thereupon,
characterized in that the liquid collection medium comprises a thin sheet of a first liquid disposed above a second liquid, the sheet being sufficiently thin to be disrupted by impinging condensed droplets or particles, to the extent that the sheet parts in a region corresponding to the impingement so as to reveal a surface of the second liquid and permit direct access of the condensed particles or droplets to the underlying second liquid for absorption therein, and wherein the thin sheet remains as a protective covering over a remaining portion of the surface of the second liquid.
18. The apparatus of claim 17 , wherein the first liquid comprises a salt flux.
19. The apparatus of claim 17 , wherein the second liquid comprises the condensed vaporous material.
20. The apparatus of claim 17 , wherein the second liquid is a molten metal.
21. The apparatus of claim 1 , wherein the vapour comprises a metal or metallic material.
22. The apparatus of claim 21 , wherein the vapour is a metal selected from Mg, Zn, Sn, Pb, As, Sb, Bi, Si, Cd, and combinations thereof.
23. The apparatus of claim 17 , wherein the second liquid comprises molten magnesium.