In continuing the previous report (Part.I),the authors reported the reults of studies on hardening strengths of (1) common magnesia cement from light burned magnesia obtained by calcining sea-water magnesium hydroxide and dilute bittern solution in salt making plants, and then (2) special,dolomite-magnesia cement from light burned (at 700-750°C) dolomite and light burned (at 750-800°C) magnesia from sea-water magnesium hydroxide.
The bad effect of free lime contained in light burned magnesia on the hardening strength of magnesia cement,could be excluded by adding magnesium sulphate nearly equivalent to free lime,reacting as the formula Ca (OH)₂+MgCl₂ aq.→CaSO₄middot;2H₂O+Mg (OH)₂.
The above mentioned special dolomite-magnesia cement by adding the light burned dolomite to the light burned magnesia in proportions 30-40 parts to 70-60 parts and kneading with dilute (Bé.22-24°) bittern solution,with or without magnesium sulphate to exclude the bad effect or free lime contained in both of light burned dolomite and magnesia,as the above mentioned formula.

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