Improvements in or relating to the treatment of aluminiumsilicon alloys

A composition, preferably in tableted form, for addition to hypereutectic aluminium-silicon alloys for degassing and grain-refining, comprises in admixture: (a) elemental phosphorus e.g. 1-50 parts by weight; (b) halogen-generating compound e.g. 5-90 parts by weight; with or without (c) grain-refining salt which liberates Ti, B or Zr e.g. 0-40 parts by weight and (d) carrier material e.g. 0-90 parts by weight. Examples of (b) may be chlorinated hydrocarbons such as C2Cl6, of (c) may be a fluoride or complex fluoride (titanfluoride or borofluoride) of Ti, B or Zr such as K2 Ti F6, and of (d) may be halide salts such as KCl. Specification 792,172 is referred to.