DE400661C - Process for utilizing the black liquor that is omitted in the manufacture of soda cellulose - Google Patents

Description

Process for the utilization of the soda pulp production omitted black liquor. When the wood is broken down by alkaline lyes arise from the reaction of alkali with wood components, especially with the Lignin, acetic acid compounds, especially sodium acetate, its extraction in unchanged or implemented state for the economic viability of the process of - more significant This is important because the acetate makes up several percent of the weight of the wood.

The invention provides a method by which the acetate component the black liquor can be recovered usable.

That. new process takes advantage of the fact that an acetate content the alkali up to a well-known concentration, which is around 15 percent lying around does not interfere with the digestion process by the lye in any way, so that the possibility is given to work in such a way that the Aufschlusshuge on one such acetate concentration levels are maintained that the useful recovery of the acetate made possible.

If, for the purpose of performing such a procedure, the lye i is used in a cycle, in that after each use the water removed from the wood Black liquor from the largest by pressure heat treatment in a manner known per se Part of its organic components is freed, it takes place with each new use one more securing of the lye, and one only needs to use the one from the each time Black liquor flowing off from wood or from the largest by pressure heat treatment Part of its organic components freed black liquor to emit a certain amount and to replace it with new acetate-free alkali in order to keep the desired alkali Maintain concentration in the company.

The useful extraction of the acetate from the discharged from the farm Lye can be done by dry distillation in the presence of superheated steam, woä be; one preferably the dry residue of the evaporated acetate-containing liquor Salts of divalent metals added as contact substances to the yield of acetone to increase.

According to the method of the invention, one works in the following way: The wood to be digested is treated in the usual type with alkali, preferably with caustic soda. This caustic soda absorbs the substances that encrust the pulp of the wood and partially settles them around, in particular sodium acetate is formed, on which it is in the new Procedure matters in the first place.

The black liquor is subjected to pressure heating in a known manner, whereby the largest part of the organic admixtures is partly deposited as precipitated coal, partly as tar. After separation of the excretion so brought organic Substance and causticizing with quicklime are combined Acetate-containing caustic alkali, which so long in the cycle to break down new Wood mass is used until the acetate has accumulated to about 10 to 15 percent Percent has learned. Once this state is reached, the whole will stop Black liquor freed from its organic components by pressure heating Causticization is fed into the company, but a certain part of the black liquor is used ejected before causticizing, which corresponds to the amount of acetate, which has formed in the liquor during the individual digestion process. The finite The amount of alkali discharged from this emitted amount of caustic becomes {uh, fresh alkali replaced. In this way one works in a cycle using the lye.

The ejected alkali containing acetate is evaporated to dryness and the dry residue, as mentioned above, further processed by distillation. If acetone is to be obtained from it, then it is advisable to process it further on your way to carry out dry distillation in such a way that you get your dry residue Chalk or another salt of a divalent metal is added and dry distillation in the presence of superheated steam.

After the dry distillation has been carried out, a residue remains, which contains carbonate of alkali and by causticizing with quicklime in the usual way Way implemented in caustic potash «which can be used to replace the from your company during the decomposition of the IIc, Izes belititzt acetates containing latige can be.

Instead of chalk can be used as a contact substance to improve the Yield of acetotes with dry distillation also calcium acetate, barium acetate, Barium carbonate or any of the many other useful salts of divalent metals : Metals are used.

Claims (5)

PATLN T-AN PROBLEMS: i. Process for utilizing the black liquor which is omitted in the sodium cellulose production, characterized in that the .iUifschlatige used in the circuit is kept at a high sodium acetate concentration while ensuring the desired degree of concentration by expelling part of the black liquor, which has largely been freed from organic matter and replacing it with fresh alkali. 2. The method according to claim i, characterized in that that that which is essentially free of organic matter and expelled from small factories N atriuinazetatl; isting is processed on acetone. 3. Method according to claim i and 2, characterized in that the acetone to be processed -. \ Tatrituiiazetat-1ösung evaporated to dryness and distilled in the presence of superheated steam will. Method according to claim 3, characterized in that the dry distillation of the residue containing sodium acetate at a temperature of around 400 ° C carried throws. 5. The method according to claim i to 3, characterized in that that the dry residue of the sodium acetate solution before distillation with salts of divalent metals, e.g. B. kohlensatirein or acetic acid calcium or Barium, is mixed as a contact substance.