US1249287A

US1249287A - Manufacture of chemical sulfate pulp.

Info

Publication number: US1249287A
Application number: US81616814A
Authority: US
Inventors: Charles N Waite; Josef E Hedin
Original assignee: Individual
Current assignee: Individual
Priority date: 1914-02-03
Filing date: 1914-02-03
Publication date: 1917-12-04
Anticipated expiration: 1934-12-04

Description

integer.

' particularly to the solution which is used in sans CHARLES Ill. WAI'IE AND JOSE]? E; HEIJIN, 0F WILMINGTON, DELAWARE, ASSIGNUAS Um I ONE-THIRD T0 "WILLIAM H. SHARP, 0F PHILADELPHIA, PENNSYLVANIA.

Ito Drawing.

To all whom it may concern:

Be it known that we, CHARLES N. "Warm and J osnr E. HEDIN, of the city of Wilming ton,-c0unty of Newcastle, and State of Dela- Ware, have invented certain new and useful Improvements in the Manufacture of Chemical Sulfate-Pulp, whereof the following is a specification. Our invention relates to improvements in the art of manufacturing chemical sulfate pulp as used in paper manufacture, and more such processes for the purpose of cooking or digesting the wood. Sodium sulfid has heretofore been used'in solution for this purpose, but it has been customary to obtain the sodium sulfid by the smelting of sulfate of soda with a mixture of carbonate of soda and organic matter contained in theblack liquor as the result of a preceding process .of digestion. I

According to our process, we obtain the sulfid of sodium in the digesting liquor by the direct addition of sulfur toa caustic soda solution.

In the practice of our process we add to a solution of caustic soda (say about seven per cent. or eleven degrees Baum) a suficie'nt amount of sulfur to produce a suitable quantity of sodium sulfid by reaction with the caustic soda. 'For ordinary purposes, we find that the addition of sulfur in the amount of about two per cent. of the total liquor used produces goodresults. The sulfur should be added to the caustic soda solution while boiling, and the process should be continued for about three hours before the liquor is ready for use. f

As the result of the addition of the sulfur a portion of the caustic soda has been converted intosodium sulfid leaving additional caustic soda not adected. The liquor thus formed is added in the usual digester to the wood and the process of digesting practised asknown to those skilled in this art;

In this process'the liquor digests the wood with formation of a waste black liquor which is drawnod from the wood pulp which is to be used in paper manufactured Thereafter the Waste liquor is returned arid from it carbonate of soda is recovered by the usual process which consists in evaporating the water and burning outthe organic matter which leaves carbonate of soda.

Specification of Letters Patent.

This carbonate of soda is then dissolved and lime MANUFACTURE 01E CHEMICAL SULFATE PULP.

added for the production of caustic soda. Accordmg to our process it is'convenient to Patented men. A, IAI "I. Application filed February 3, 19M. Serial Ito. MAMA add the sulfur required alongwith the lime during this causticizing process, thereby avoiding the necessity of a separate process for the production of the sodium sulfid.

- After having thus added the sulfur during the causticizing process with the production of sodium sulfid, the liquoris then again usedand the process repeats itself.

By our process the formation of the digesting' liquor is much simplifiedl The use of any smelting process is avoided and the proportion of sodium sulfid in the liquor may be regulated with much greater nicety than in previous processes. I

There 1s a corresponding savlng 0f the cost of raw material.

Having thus described our invention, we

claim: 1

. 1. The process of manufacturing liquor to be used in thedigestion of wood pulp, which consists in taking the spent liquor remain ing from a previous digestion, evaporating the Water therefrom, burning out the organic matter contained, dissolving the resulting sodium carbonate and at the same time adding lime, wherebycaustic soda is produced, and sufiicient sulfur; to convert part of the caustic soda into sodium sulfid, and using the liquor thus produced for a succeeding process of, digesting wood.

2. The process of digesting wood pulp for the manufacture of paper, which consists in adding to a caustic soda solution a quantity of sulfur sufficient to convert a portion of the caustic soda into sodium sulfid, and

thereafter adding the liquor thus produced to the wood to be digested, drawing ofi from the digested wood pulp the resulting liquor, evaporating the water therefrom, burning the organic matter, dissolving the remaining carbonate of soda and adding thereto lime and sulfur whereby there is produced a solution containing caustic soda and sodium sulfid and using the liquor thus produced for a succeeding process of digesting wood. In testimony whereof, we have hereunto signed our names at Philadelphia, Pennsyl- Vania, this thirty-first day of January, 1914.

CHARLES N. WAITJE. JUSEF 1E. I-IEDIN.