A process for separating a portion of an electrically-conductive fluid mixture of components which portion has a different concentration of a diamagnetic component than the remainder of the mixture, comprises passing the mixture under pressure through an annular passage containing a radial magnetic field which causes the concentration of the diamagnetic component in the portion of the mixture adjacent the outer wall of the passage to differ from the concentration of the diamagnetic component in the portion of the mixture adjacent the inner wall of the passage due to migration of the diamagnetic component in the field, and separating the two portions from one another. The fluid mixture may be gaseous, such as a mixture of hydrogen and helium, or liquid such as sea water. Apparatus for carrying out the process comprises a tube or pipe cored with an axially extending magnetic core and provided with circumferentially arranged outlets for separating the radially outer portion of the mixture from the remainder when flowing through the pipe or tube. The annular space between the magnetic core and the tube forms the passage through which the fluid mixture flows. The magnetic core may be formed of a series of permanent magnets arranged end-to-end and having their neighbouring poles of like polarity. For obtaining heavy water from sea water, a stainless steel pipe at each half foot distance, is provided with a circumferential drain leading into a common tank. The water enters the pipe at a pressure of 100 p.s.i. and is circulated before draining at every third circulation. The main flow is treated with H2S gas to allow deuterium exchange while heated to 100 DEG C. The sulphide and accompanying water are then run through a heat exchanger and a cold tower at 25 DEG C. so causing the water to be enriched by deuterium sulphide. Recycling through the pipe allows the water to be raised to a D2O concentration that is distilled. The collected salts are concentrated by evaporation or electrolytically separated. In subjecting uranium ore to separation the ore is ground to flotation size and added to water which is cycled through the stainless steel pipe as before. The collected solids are leached in sulphuric acid and the uranium processed. The process may be used for the extraction of components such as salt particles from sea water to produce potable water.ALSO:A process for separating a portion of an electrically-conductive fluid mixture of components which portion has a different concentration of a diamagnetic component than the remainder of the mixture, comprises passing the mixture under pressure through an annular passage containing a radial magnetic field which causes the concentration of the diamagnetic component in the portion of the mixture adjacent the outer wall of the passage to differ from the concentration of the diamagnetic component in the portion of the mixture adjacent the inner wall of the passage due to migration of the diamagnetic component in the field, and separating the two portions from one another. Apparatus for carrying out the process comprises a tube or pipe cored with an axially extending magnetic core and provided with circumferentially arranged outlets for separating the radially outer portion of the mixture from the remainder when flowing through the pipe or tube. The annular space between the magnetic core and the tube forms the passage through which the fluid mixture flows. The magnetic core may be formed of a series of permanent magnets arranged end-to-end and having their neighbouring poles of like polarity. The passage of the fluid mixture through the magnetic field may produce a magneto hydrodynamic whirl effect which causes suspended particles to be thrown against the pipe wall and broken into smaller particles. In preparing tetraethyl lead, lead compounds such as lead sulphide, lead oxide or lead dioxide may be suspended in water to form an electrically-conductive mixture and separated by the magneto hydrodynamic effect. These compounds now react readily with ethyl chloride to form tetraethyl lead. Also the reaction of lithium ethyl or sodium ethyl with lead sulphide at room temperature produces a rapid reaction with high yields.ALSO:A process for separating a portion of an electrically-conductive fluid mixture of components which portion has a different concentration of a diamagnetic component than the remainder of the mixture, comprises passing the mixture under pressure through an annular passage containing a radial magnetic field which causes the concentration of the diamagnetic component in the portion of the mixture adjacent the outer wall of the passage to differ from the concentration of the diamagnetic component in the portion of the mixture adjacent the inner wall of the passage due to migration of the diamagnetic component in the field, and separating the two portions from one another. Apparatus for carrying out the process comprises a tube or pipe cored with an axially extending magnetic core and provided with circumferentially arranged outlets for separating the radially outer portion of the mixture from the remainder when flowing through the pipe or tube. The annular space between the magnetic core and the tube forms the passage through which the fluid mixture flows. The magnetic core may be formed of a series of permanent magnets arranged end-to-end and having their neighbouring poles of like polarity. The process may be used for the concentration of free (organic) radicals in solution. For example a diamagnetic solution may be used for the conversion of parahydrogen. Thus triphenylmethyl will convert parahydrogen which may be collected. Tetraphenylidiphenoquinodimethane and stilbenoquinodimethane, both of which are diamagnetic, may be used for this purpose. Similarly, rubrene and dibenzanthracine may be employed. A further application is the promotion of hydroforming of petroleum and free radical formation in petroleum gases leading to the formation of gasoline. Petroleum gases or liquid subjected to the magnetic hydrodynamic effect react to form long chain hydrocarbons, isomerize and form alkyl and alkane compounds. Petrol may be refined by causing the formation of free radicals by ejecting ions in the gaseous state in a magneto hydrodynamc whirl and allowing the free radicals to recombine.ALSO:A process for separating a portion of an electrically-conductive fluid mixture of components which portion has a different concentration of a diamagentic component than the remainder of the mixture, comprises passing the mixture under pressure through an annular passage containing a radial magnetic field which causes the concentration of the diamagnetic component in the portion of the mixture adjacent the outer wall of the passage to differ from the concentration of the diamagnetic component in the portion of the mixture adjacent the inner wall of the passage due to migration of the diamagnetic component in the field, and separating the two portions from one another. Apparatus for carrying out the process comprises a tube or pipe cored with an axially extending magnetic core and provided with circumferentially arranged outlets for separating the radially outer portion of the mixture from the remainder when flowing through the pipe or tube. The annular space between the magnetic core and the tube forms the passage through which the fluid mixture flows. The magnetic core may be formed of a series of permanent magnets arranged end-to-end and having their neighbouring poles of like polarity. The fluid mixture may be gaseous, such as a mixture of hydrogen and helium, or liquid such as sea water. A further application is the separation of deuterium from hydrogen in the refinement of hydrogen. Deuterium exchange between hydrogen sulphide and water may be promoted whereby deuterium sulphide is concentrated. In the separation of ortho-hydrogen from para-hydrogen, the ortho-hydrogen, being paramagnetic, passes parallel to the magnets and is collected at the outlet. The para-hydrogen being diamagnetic, moves at right angles to the axis of the magnets. The passage of the fluid mixture through the magnetic field may produce a magneto hydrodynamic whirl effect which causes suspended particles to be thrown against the pipe wall and broken into smaller particles. The process may be used for the separation of heavy water present in sea water and for the extraction of components such as salt particles from sea water. In the separation of ores, the ore is ground to flotation size, suspended in water to form an electrically conductive mixture and subjected to the magneto hydrodynamic effect. The ore particles can thus be reduced to fragments of 2 microns and readily leached and concentrated.