Spiral separator and apparatus therefor

An spiral separator, for provision operatively intermediate upstream and downstream spiral trough parts of said spiral separator, the apparatus comprising:

• a slurry receiving region for receiving a mineral slurry flow from said upstream spiral trough part of said spiral separator;
• one or more splitters, configured to split the mineral slurry flow into a concentrate part, a semi-concentrate part and a remainder part, the semi-concentrate part comprising a lower proportion of more dense to less dense mineral than the concentrate part;
• and the semi-concentrate part comprising a higher proportion of the more dense to the less dense mineral than the remainder part;
• a mixing region configured to mix a more fluid radially more outward part of the remainder part with a less fluid radially more inward part of the remainder part, to provide a mixed remainder part for feeding onto the downstream spiral trough part;
• a concentrate channel for offtake of the concentrate part;
• and
• a semi-concentrate bypass channel for conveying the semi-concentrate part towards the downstream spiral trough part, such that the semi-concentrate component bypasses and is segregated from the mixing region;
• wherein the concentrate channel and the semi-concentrate channel are both, at least partially, radially inward of the mixing region;
• wherein the apparatus provides a semi-concentrate outlet configured to direct said semi-concentrate part from the bypass channel to an inner region of a working trough floor surface of the downstream spiral trough to which more dense particles migrate, in use, across the working trough floor surface, from an outer region of the working trough floor surface, at an upstream part of the downstream spiral trough part;
• and
• wherein the apparatus provides a mixed remainder outlet configured to direct said mixed remainder part from the mixing region to the outer region of the downstream spiral trough part, at an upstream part of the downstream spiral trough part.

A method of concentrating a more dense mineral provided in a mineral slurry comprising the more dense mineral and water, the method comprising:

• using an upstream stage of a spiral separator to concentrate the more dense mineral towards a radially inner side of a spiral trough of the upstream stage,
• splitting the mineral slurry, at or adjacent a bottom region of the upstream stage, into a radially inner concentrate part, a radially intermediate semi-concentrate part and a radially outer remainder part, wherein the concentrate part comprises a higher concentration of the more dense mineral than the semi-concentrate part, and the semi-concentrate part comprises a higher concentration of the more dense mineral than the remainder part;
• segregating the semi-concentrate part from the remainder part;
• mixing a more fluid radially more outward part of the remainder part with a less fluid radially more inward part of the remainder part, in a mixing region of the spiral separator to thereby provide a mixed remainder part, wherein the semi-concentrate part is segregated from the mixing region;
• and
• feeding the mixed remainder part and the semi concentrate part onto a downstream stage of the spiral separator, the downstream stage having a trough floor configured such that in use more dense mineral particles migrate inwardly from an outer region, across the trough floor, to concentrate at an inner region thereof,
• wherein the semi-concentrate part is fed to the inner region of the downstream stage at an upstream part of the downstream stage;
• and the mixed remainder part is fed to the outer region of the downstream stage at an upstream part of the downstream stage.