US841190A - Manufacture of purified soda-pine pulp. - Google Patents

Description

WILLIAM H. SHARP, OF PHILADELPHIA,J/PENNSYLVANIA.

MANUFACTURE OF PU RIFIED SODA -PINE PULP- Specification of Letters Patent.

. Patented Jan. 15, 1907.

Application filed November 6, 1908. Serial No; 342.172.

it whom it may concern: I

Be it known that 1, WILLIAM H. SHARP, residing at No. 1813 Chestnut street, in the. city of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a certain. new and useful Im i'ovement in the bianuiaoture of Purified ode-Pine Pulp, whereof the followin is a specification.

As indicated in the above statement, my process is limited to the manufacture or the pulp or cellulose from pine-wood as distin-r guished from other kinds of 'wood, and it. is also limited to the so-called soda process, whereby the wood is primarily digested.

Without attem ting to indicate all the varieties of pine w ose similar characteristics render them amenable to treatment by my process, the following may be stated as typical ofsuch varieties, the commercial name in each instance being stated as most 'ob viously d'escriptive-viz., short-leaf sprhcepine, loblolly-pine, ioxtail pine, long leaf pine, old-field pine, jack-pine, :ci ger-prneL When the soda process is emp oyed upon pine-wood of this character, it is found that at the conclusion of the process there are re-- sidual substances which resist the urifying reagents and which discolor the pu to the serious impairment of its commercial value. These substances do not yield tc'the bleaching agent usually cm loyed-viz., ordinary bleaching-powder or clilorid of limebut are extremely persistent; and the object of my present invention is I substances so that they shall no longer imto remove or modify the To this end I conduct the process as follows: The pine-wood in the form oi chips or small fragments is first digested with a solution of caustic soda of the pair the product.

strength of ab0ut 12 to 13 .Baum for about ten hours at a pressure of about one hundred and twenty pounds. It is then thoroughly washed with water, and after washing it is treated with bleaching-powder of chlorid of lime, about twenty pounds of this reagent being used to each one hundred pounds of the washed pulp. After the action. of the blcaching-pmvder is nearly exhausted I. add about five pounds of a permanganate salt, preferably permanganate of potash or permanganate of soda, to one ton of the pulp. The mass is then stirredsigned my name, at Philadel thoroughl and as soon as the color indicates that the csired reactions are obtained it is washed with a dilute solution of sulfurous acid until all the soluble traces of the manganous compounds have been removed. The

pulp is then ready for use in the ordinary manner.

Having wish it to thus described my invention, I be unde'rstood that I do not claim, broadly, the use of a ermanganate in connection with the bleac in of pul for I am aware that in the so-ca led sulf ite .process for the manufacture of ulp permanganate has been used. Its use, owever, so far as am aware, has been at a difierent stage of the process and in eatly larger percentages than the one which I employ. The soda process,'to which my invention 1s limited,-presents entirely different conditions at that stage in which I'emplo the permanganate, and although the de ective character of the ulti-- mate'product of the soda process in the particulars above named has long been known and the desirability of a remedy therefor has been fully a preciated, it has not, so far as I am aware, een deemed possible to obviate the difficulties. of novelty upon the discovery that where pins-wood is subjected to treatment by the so-call ed soda process the reactions which occur and the resultant condition of the product which is attained after the usual leaching stage has been completed are such I therefore base my claim as to permit the successful use of a relatively small amount of permanganate for removing the last and persistent traces of discoloring material.

I claim I The hereinbefore described.process of man uiacturing sodainepulp, which consists in, first, digesting thepine-wood with a caustic soda; second, washin third, treating with chlorid of lime; fourt treating with a ermanganate; and, finally, washing in a di ute sulfurous acid, substantiall as set forth.

In testimony whereof have hereunto hia, Pennsylvania, this 5th day of Novem er, 1906.

, WILLIAM H. SHARP. -Wi-tnesses:

JAMES H. BELL, E. L. FULLERTON