A horizontal mixer (20,50) for producing a slurry from which isotopes may be produced, comprising: a container comprising a rotational axis that is horizontally disposed, an inner sidewall disposed about said rotational axis, and a mixing chamber defined at least in part by said inner sidewall; a plurality of blades that extend from said inner sidewall toward an interior of said mixing chamber; and an outlet (26,72) from said mixing chamber of said container, wherein each said blade extends along said inner sidewall in an orientation relative to said rotational axis to direct fluid toward said outlet during rotation of said container in a first rotational direction about said rotational axis, wherein said container further comprises first and second container ends (86a, 86b) that are spaced along said rotational axis, wherein said plurality of blades comprises a plurality of first blades and a plurality of second blades that each extend from said inner sidewall toward said interior of said mixing chamber and that each comprise first and second blade ends (94,96), wherein each said first blade extends from its corresponding said first blade end toward its corresponding said second blade end at least generally in a direction of said second container end, wherein each said second blade extends from its corresponding said first blade end toward its corresponding said second blade end at least generally in a direction of said first container end, and wherein said first blade end of each said plurality first and second blade leads its corresponding said second blade end in said first rotational direction for said container, and wherein said first container end comprises an aperture, and characterised in that said horizontal mixer further comprises an outlet conduit (74a,74b,76) that extends through said aperture and to a location in a longitudinal dimension that is between said second ends of said plurality of first blades and said second ends of said plurality of second blades, and wherein said longitudinal dimension coincides with said rotational axis. a container comprising a rotational axis that is horizontally disposed, an inner sidewall disposed about said rotational axis, and a mixing chamber defined at least in part by said inner sidewall; a plurality of blades that extend from said inner sidewall toward an interior of said mixing chamber; and an outlet (26,72) from said mixing chamber of said container, wherein each said blade extends along said inner sidewall in an orientation relative to said rotational axis to direct fluid toward said outlet during rotation of said container in a first rotational direction about said rotational axis, wherein said container further comprises first and second container ends (86a, 86b) that are spaced along said rotational axis, wherein said plurality of blades comprises a plurality of first blades and a plurality of second blades that each extend from said inner sidewall toward said interior of said mixing chamber and that each comprise first and second blade ends (94,96), wherein each said first blade extends from its corresponding said first blade end toward its corresponding said second blade end at least generally in a direction of said second container end, wherein each said second blade extends from its corresponding said first blade end toward its corresponding said second blade end at least generally in a direction of said first container end, and wherein said first blade end of each said plurality first and second blade leads its corresponding said second blade end in said first rotational direction for said container, and wherein said first container end comprises an aperture, and characterised in that said horizontal mixer further comprises an outlet conduit (74a,74b,76) that extends through said aperture and to a location in a longitudinal dimension that is between said second ends of said plurality of first blades and said second ends of said plurality of second blades, and wherein said longitudinal dimension coincides with said rotational axis.