Die Trennung des Calciums vom Magnesium nach dem Oxalatverfahren

Inorganic Gravimetric Analysis

“…The nitric acid solution of the alloy was evaporated in the presence of oxalic acid crystals, the residue was ignited, and the calcium was extracted with water and subsequently was precipitated as oxalate at pH of about 5 and ignited to calcium oxide. Karaoglanov (163) reported that calcium could be separated very nicely from magnesium over certain concentration ratios if considerable excess of oxalate was used and the calcium oxalate was filtered after one hour. While filtering was difficult, there was no appreciable interference from magnesium.…”

Separation of Calcium from Magnesium by Oxalate Method in Samples of High Magnesium-Calium Ratio

“…It has been clearly shown (I, 3, 5, 6, 7) that in magnesium-calcium ratios (by weight) of 1 to 1 or lower a better separation is attained by slow neutralization of an acid oxalate solution than by addition of oxalate to a neutral solution. In this case, sufficient oxalate according to Figure 2 is not always added and it is necessary to depend upon supersaturation to keep magnesium oxalate from precipitating (4).…”