Hard water boiling. When this is the case, it is usually caused by the presence of calcium sulphate/calcium chloride and/or magnesium sulphate/magnesium chloride in the water, which do not precipitate out as the temperature increases. Ions causing permanent hardness of water can be removed using a water softener, or ion exchange column. Total Permanent Hardness = Permanent Calcium Hardness + Permanent Magnesium Hardness With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather, because the 2+ ions destroy the surfactant properties of the soap by forming a solid precipitate (the soap scum). A major component of such
Magnesium the commercial aerospace industry, magnesium was generally restricted to engine-related components, due to fire and corrosion hazards. Currently, magnesium alloy use in aerospace is increasing, driven by the importance of fuel economy. Development and testing of new magnesium alloys continues, notably Elektron 21, which (in test) has proved suitable for aerospace engine, internal, and airframe components. The European Community runs three R&D magnesium projects in the Aerospace priority of Six Framework Program. In the form of thin ribbons, magnesium is used to purify solvents; for example, preparing super-dry ethanol. Both AJ62A and AE44 are recent developments in high-temperature low-creep magnesium