Untitled record

IMPERIAL

PATENT OFFICE.

According to DRP No. 43977 of 17 July 1887, decomposed aluminate liquors are obtained in which the ratio of the molecular weight of AL₂ O₃ : JVa₂ O is about as 1: 6 behaves. These act according to my observations in many cases like caustic soda. In the process protected by the above-mentioned patent, after evaporation, these solutions were mixed again with bauxite and exposed to the heat of the flame furnace, to recover raw aluminate from it, which decomposes again after dissolution and filtration.

According to my research, these solutions are now capable of reaching 40 to 44⁰ B. are evaporated to dissolve the bauxite directly from the bauxite, if the same with the evaporated solutions with continuous stirring at a pressure of 3 to 4 atmospheres and the corresponding temperature (160 to 172⁰C.) by 1Y₂ treated up to 2 hours.

If the bauxite was finely powdered enough and there is not much silica present, then the clay is dissolved up to traces bezw. except for an amount which with the approximately dissolved silica and the corresponding amount of soda as the known double compound Na.₂ O AL₂ O₃ 3 Si O₂ + 9 aq remains.

In the usual processed red French bauxite with 61 pCt. AL₂ O₃ and about 3 pCt. Si O₂ are regularly 59 pct. the solution is dissolved in solution when the decomposed leachate and the bauxite are brought together in proportion to the result, after treatment, of a solution having a molecular ratio of 1 to 2₂ O₃ : Na ,, O = 1: 1.75 to 1.85; this corresponds to a yield of at least 96 pCt. the existing clay soil.

The apparatus necessary for this purpose is a pressure vessel made of half-inch sheet iron with the necessary fittings, as a safety valve, stirrer, pressure gauge, pressure tube and filling opening. As can easily be seen, the same can be for a considerable production of comparatively small dimensions, which excludes any danger in working. Similarly, the consumption of fuel and manpower to operate a very insignificant and hardly worth mentioning. For example, in a pressure vessel of 2^]/₂ m length and 1 m diameter daily about 4000 to 5000 kg of bauxite are digested, and the consumption of fuel and labor for this hardly Y.₁₅ from that required for one or more corresponding flame furnaces, except that one obtains already finished solution, while you must first prepare the solution from the dry raw aluminate when working with flame furnaces.

The red iron-containing residue remaining after the digestion settles well and, in some practice, is easily filtered

Wash. Because of its high iron and low clay content, it can still be suitably processed or fused with other iron ores to iron.