Abstract
In the previous report (4), the formation of basic magnesium hypochlorite by a non-diaphragm electrolysis to separate magnesium dissolved in sea water was studied, but magnesium could not be removed completely, and the amount of precipitate was so little its composition could not be considered.
In this report, magnesium chloride solution containing 1.7 mol per litre of magnesium was used, and the effects of electrolytic factors on the formation of basic hypochlorite and the formation of hypochlorous acid, hypochlorite and chlorate in electrolyte were studied. Factors that had been employed were amount of sodium chloride, current density, distance between electrodes, quantity of electrolytic current, temperature, leaving time after electrolysis, and the effect of calcium. And also oxidation current efficiency, decomposition ratio of chloride, and removal ratio of magnesium were determined.
Formation of basic hypochlorite was affected significantly by temperature and leaving time after electrolysis relating with the reaction velocity of magnesium hydroxide and hypochlorite. The amount of precipitate and of the hypochlorite in precipitate were reached to a maximum value at 50°C, and these amounts were increased considerably by the leaving time of 24 hours, and also were reached to a maximum value at 72 hours. Compositions of basic magnesium hypochlorites were varied by the conditions of their preparations, and the mole ratios in precipitates that obtained were Mg(ClO)2: Mg(OH)2: H2O=1:18.5-3.1:11.3-0, but they gave a same results by the X-ray diffraction, and showed the patterns indicating diffused bands of weak intensity at 13°, 36° and 59°(2θ).
In the electrolysis of brine, amount of precipitate was increased more than in magnesium chloride solution, but amount of precipitate was increased more than in magnesium chloride solution, but amount of hypochlorite in precipitate was decreased, so the effect of addition of sodium chloride was recognized. But, in this case, removal ratio of magnesium was not so much as 17 percent.
It was considered to be difficult to remove completely magnesium by a process of formation of basic hypochlorite.
