(2) The difficulty experienced in preserving caustic soda in a powdered state, owing to the tendency of its particles when exposed to the atmosphere, to deliquesce and combine and mass together, is said to be overcome by mixing with the soda a quantity of powdered sand sufficient to protect the particles of soda from such contact with each other as will cause them to mass together, and also sufficient to shield, in a measure, the particles of caustic from contact with the atmosphere. Caustic soda thus treated is applicable generally in the arts, an 1 can be handled with greater facility than the ordinary commercial article. Where it is to be used as a flux in the manufacture of cat iron, 1 part ground sand may be used to 5 of ground caustic soda; but the quantity of sand may be materially increased, though a less amount will not prove effective. While the sand operates in a measure to protect the soda from atmospheric influences, and prevent contact of its particles, there is no chemical combination between the sand and soda which would cause it to solidify and harden, as would be the case were powdered limestone, for instance, used. In practice the soda and sand are ground up to a powder, either separately or together, and immediately mixed.
From the facility with which the article prepared can be handled, it is especially adapted for use as a flux in the manufacture of cast iron, though for the same reason it also commends itself to the trade generally.