DE567114C - Manufacture of clay - Google Patents

Description

GERMAN EMPIRE

ISSUED ON
DECEMBER 28, 1932

REICH PATENT OFFICE

PATENT LETTERING

JVl 567114 CLASS 12 m GROUP

Jean Charles Seailles in Paris manufacture of clay

Addendum to patent 564

Patented in the German Empire from July 6, 1928 The main patent started on February 26, 1927.

is used.

The invention relates to an improvement on that described in patent 564059 Process for the production of alumina.

It has also been found that digesting halogen-free clay minerals can advantageously use two or more alkaline earth or alkali bases at the same time, one of which gives soluble aluminates and the other insoluble alkaline earth aluminates. The presence of soluble aluminates as intermediates facilitates surprisingly Wise the reaction, and the yield will be increased. At the same time can Achieve a high degree of purity in the end product by reducing the solubility of the silica is decreased.

As a soluble aluminate-forming base, barium oxide or caustic soda or caustic potash and be used as insoluble aluminate-forming base lime, namely the lime forms the Main digestion base, while the base which gives the soluble aluminate is by formation soluble intermediates acts as a catalyst.

You can, for example, a mixture of lime, barite, bauxite and in the autoclave Treat water; a mixture of lime, caustic soda or its educational mixture could also be used, Bauxite and water.

The amount of lime should be at least equal to that which is necessary to precipitate all of the alumina that can be bonded with barite or caustic soda as calcium aluminate. Under these conditions, the barite or caustic soda, which remain dissolved in the water, is recovered when it is withdrawn from the autoclave, and they can be used again indefinitely, with almost no loss; the calcium aluminate is obtained as a sludge mixed with the other residues. This calcium aluminate can be further treated by known processes and gives clay; for example it can be treated with soda to form soluble sodium aluminate and insoluble calcium carbonate. This aluminate is then _{precipitated by CO 2} or otherwise processed using known methods.

Example treatment of a bauxite of the following

Composition:

56.50 ο / ο

SiO ₂ 3> ^χο Fe ₂ O ₃ 24.8ο -

. FeO 3j °° ■

H ₂ O 12.50 -

99.90.

There are mixed:

100 parts by weight of this bauxite, 150 parts by weight slaked lime, 200 parts by weight of water, 20 parts by weight of NaOH.

The finely ground mixture is ^{boiled in the autoclave for about 1} _1/2 hours under 5 kg of steam pressure.

The product is then allowed to settle and then the liquid is drawn off. It is then leached and exhausted with sodium carbonate in 10% solution at about 80 ° with stirring. After the liquid has been drawn off, the residue is washed with a 50% alkali at the same temperature. _{The ALO 3} is then precipitated in the known manner by means of CO ₂ in the alkaline solutions obtained.

The yield is high, reaching 94 to 95 o / g of the alumina; the product received is very pure, and the analysis shows:

99.740 / 0 Al ₂ O ₃
0.26 o / o SiO ₂ .

Claims (1)

Claim: Process for the production of alumina according to patent 564 059, characterized in, that. in the digestion to form an insoluble alkaline earth aluminate ErdalkaEbase a small amount of a soluble aluminate forming alkali or alkaline earth base or a mixture such bases is added.