DE96467C - - Google Patents

Description

PATENT OFFICE.

The present process aims to regenerate the alkalis from the waste liquors the sulphite and sulphate pulp manufacture by treating them with or alumina Materials (e.g. bauxite) and leaching of the alkalis as alkali aluminates. Since to achieve pure end products the organic substances of the waste liquor must be destroyed by evaporation and annealing, see above During this process, the sulphurous salts (sulphates, Sulphonates, sulphites and sulphides) are all converted into sulphurous alkalis, which the formation prevent aluminates. In order to remedy this inconvenience, in the present process one relies on clay an amount of lime, iron, and the like, equivalent to the sulfur content of the lye Sulfur-binding materials too.

This process now also permits those which necessarily occur in the course of manufacture Loss of alkali by adding an appropriate amount of sulfate or bisulfate to the To cover the calcining pan completely, while with the present regeneration process the Soda or Sulphate - cellulose factories always limit this addition to a certain level had to stay, since with a larger content of sodium sulphide (which is derived from the sulphate or bisulphate forms when calcined under the influence of organic substances) in the finished cooking liquor the quality of the cellulose suffers.

The practical implementation of the method is therefore, for example, like. follows:

The lye from the cookers and the fabric washers are made according to the well-known Methods evaporated. At any stage of the evaporation process, preferably in the calcining pan, the thickened waste liquor is powdered bauxite or something else alumina-containing material added in such an amount that the alkali of the thick Leaching all alumina is converted into alkali aluminates. At the same time you put the fat one Waste liquor an amount corresponding to the sulfur content (to be determined by analysis) carbonate of lime (limestone) or caustic lime in pieces about the size of a bean. The bauxite and the limestone can also be used in special. Apparatus, for example in rotating cookers and like. brought together with the waste liquor and the resulting liquid then evaporated will.

The from the Calcinir- bezw. Drawn melting furnaces Reaction mass, which contains the alkali for the most part as alkali aluminate leached by known methods with water and the solution from the residue either separated by allowing it to sit down or with the aid of a filter press. The residue is washed out and the washing water is used to leach out a new batch of reaction material.

The obtained kare solution, which mainly contains alkali aluminate and its

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Concentration corresponding to the strength of the liquid that will later be used for pulp manufacture must be chosen, is now according to the type of process of the relevant cellulose factory further treated in the following two ways:

A. For soda or Sulphate pulp mills.

Carbonic acid is introduced into the solution of the aluminate. This makes pure alumina hydrate precipitated and obtained a solution of the carbonic acid alkali. The solution to the Carbonate alkali is causticized in a known manner by quicklime and the obtained Lye used for pulp production. The alumina hydrate is passed through a filter press separated from the liquid, washed out and further treated as described later. the The necessary carbonic acid is expediently taken from a lime kiln, and at the same time Caustic lime obtained is used for gasification.

B. For sulphite pulp mills.
Sulphurous acid is passed into the solution of the aluminate, pure alumina hydrate being precipitated and a solution of sulphurous alkali resulting. The products obtained are separated as in the above method and the solution of the sulphurous alkali used for pulping the pulp raw materials. The sulphurous acid is obtained in a known manner by burning sulfur, gravel, etc. The alumina hydrate, which precipitates in the purest state (almost chemically pure) in both methods, can either be dried and then used in the aluminum industry, or it becomes as moist as it comes from the filter press in hot sulfuric acid at 60 ° B. registered and converted into sulfuric alumina, which is known to be used en masse in paper manufacture for gluing. It can also be used to produce aluminum salts for dyeing purposes.

The loss that occurs naturally in all pulp mills in the course of manufacture In both methods, alkali is obtained by adding sulphate (including bisulphate) to the CaI-cinir pan covered. These materials are in front. the introduction of the bauxite into the thick lye bring in and stir well. Of course, it has to bind the sulfur a corresponding amount of limestone can also be entered.

Claims (1)

Patent claim: Process for the regeneration of the alkalis from the waste liquors of the sulphite and sulphate cellulose production by means of clay or materials containing clay (e.g. bauxite), thereby marked that the waste liquors, in addition to the alumina, have an effect on the sulfur content of the liquors appropriate addition of lime and the like. Is given.