Example 2
A ton of so-called "mean" berylliferous pegmatite of Valmasul (Bolzano) containing 7.5% of beryllium oxide is treated as in the preceding example but with a quantity of 470 kgs. of precipitated calcium fluoride such as Is freshly collected in a subsequent phase of the operation which will be described hereinafter, and 1500-1600 kgs. of a salt-acid solution containing about 45-46% of sodium nitrate and 24-25% of nitric acid such as the solution obtained in a subsequent phase of the operation as hereinafter described. As in the preceding example, the paste is burnt, after having been well compressed in order to extract from the same all the calcium and sodium salts which it contains, at a temperature of about 650" C. during about two hours and then submitted to the lixiviation.
The precipitation of the beryllium hydrate is obtained by means of the sodium ion extracted from an electrolyzer of the mercury type which decomposes the sodium chloride. As in the preceding example the beryllium hydrate which has been precipitated in the electrolyzer is separated in a filter press and the mixed solution of nitrated and fluorinated sodium salts from the electrolyzer is mixed with the liquid which has been expelled in the first place from the briquettes and which contains calcium salts. In the vessel which contains the mixture calcium fluoride is formed again, by precipitation, and, after having been separated by decantation, this calcium fluoride is conveyed to the first phase of the operation.
The liquid which separates from the calcium fluoride by decantation is composed of a solution of sodium nitrate alone, which is conveyed to a vacuum concentration apparatus until a concentration of about 50% of salt Is obtained.
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