SULFATE PULPING OF PONDEROSA PINE TI-IINNINGS

Transcription

1 SLFATE PLPIG F PDERSA PIE TI-IIIGS ctober 1951 \13171, FEB ITED STATES LI1EPARTMET F AGRICLTRE werest SERVICE FREST PRDCTS LABRATRY Mdison 5, Wisconsin In Coopertion with the niversity of Wisconsin

2 SLFATE PLPIG F PDERSA PIE TIIGS BY J STALEY MARTI, Chemicl Engineer Forest Products Lbortory,1 Forest Service S Deprtment of Agriculture Introduction Ponderos pine (Pinus ponderos) wood obtined in thinning opertions on stnd ner Blnchrd in western Idho ws experimentlly pulped by the sulfte process to determine its pulping chrcteristics In such thinning opertions, some trees re cut to give better spcing to the remining trees, nd some trees of poor form nd vigor re removed to improve the qulity of the stnd, If stisfctory pulps could be produced from the pine thinnings, use would be provided for the wood cut in such forest-mngement prctices Test Mteril nd Pulping Procedures The test mteril consisted of 83 bolts, ech 4 feet in length, nd ws representtive of wood obtined by combintion of thinning opertions t the crown nd lower levels of the tree It ws obtined from smll stnd of pure ponderos pine contining trees 2 to 4 yers old, 4 to 1 inches in dimeter t brest height, nd 15 to 3 feet in height Pure stnds of lodgepole pine occurred in the generl re The physicl chrcteristics of the ponderos pinez re given in the following tbultion, which lists verge vlues obtined on representtive trnsverse sections, pproximtely 1 inch thick: Specific grvity 4 Density pounds per cubic foot 25 Dimeter inches 49 Age yers 368 Rte of growth rings per inch 149 ertwood, by volume percent 19 Brk, by volume 4 IF do 29 Brk, by weight (dry bsis) do 199 ** Mintined t Mdison, Wis, in coopertion with the niversity of Wisconsin?Pinus ponderos Shipment o 2814 Report o R Agriculture-Mdison

3 The density of the ponderos pine, 25 pounds per cubic foot (bsed on weight of moisture-free wood nd volume of green wood), ws within the rnge of common northern coniferous pulpwoods, such s jck pine, Dougls-fir, western hemlock, Pcific silver fir, nd lodgepole pine If it is stisfctory s pulpwood, the ponderos pine might be expected to compete in the sme mrket s these woods The ponderos pine resembled jck pine, wood used extensively in the Lke Sttes pulping industry, closely enough in chemicl composition to indicte similr sulfte=pulping chrcteristics for both species It hs slightly lower lignin content nd little higher solubility in lcohol-benzene nd in ether thn jck pine (tble 1) Vrious rtios of pulping chemicl to wood were used to produce sulfte semichemicl, krft, nd bleching sulfte pulps The pulping digestions were mde in sphericl,' rotry utoclve, which ws indirectly heted by stem nd hd cpcity of 5 cubic foot Semichemicl pulps were fiberized in n ttrition mill hving n 8-inch, single rotting disk, nd yields nd strength properties of the fiberized pulps were determined Results nd Discussion In the semichemicl pulping series, n increse in the mount of chemicls (clculted s sodium oxide) from 78 to 117 percent of the weight of moisturefree wood cused norml decrese in pulp yield from 73 to 54 percent, decrese in chemicl consumption, n increse in the density of the blck liquor, nd progressively higher strength Properties of the semichemicl pulps (tbles 2, 3) The pulps cooked with less thn 117 percent of chemicls were very drk in color, s mesured by brightness vlues, nd were similr in brightness to high-yield pulps from softwood species In the digestion in which the smllest mount of chemicls ws used, cooking ws stopped when the mximum temperture ws reched, thereby mking the totl cooking time one-hlf tht of the other digestions The result ws higher pulp yield of 75 percent nd lower strength properties, exce pt for tering strength, which showed no chnge While ll the sulfte semichemicl pul ps ppered to hve more thn dequte strength for corrugting bord, the ponderos pine sulfte pulp produced in yield of 54 percent lso ppered to hve sufficient strength for use in liner bord of high qulity The pulping of ponderos pine by conditions suitble for producing krft-type pulp (137, 156,nd 176 percent of sodium oxide) showed tht the lowest quntity of chemicls ws sufficient to produce the mximum yield of screened pulp, low yield of screening rejects, nd the highest pulp strength (tbles 2, 3) The yields of screening rejects obtined for the krft digestions were lower thn those normlly obtined from jck pine nd mny softwood species, which indicted very fvorble pulping chrcteristics for ponderos pine by the sulfte process Ponderos pine krft pulps were higher in bursting strength nd lower in tering strength (tble 3) thn southern pine pulps The bursting strength of ponderos pine krft pulps ws considerbly lower thn tht of spruce nd blsm krft pulps The krft pulps from ponderos pine were quite similr in strength to those from jck 7)ine nd pper to be suited for use in the sme Report o R199-2-

4 types of ppers, such s wrpping nd krft specilties, s the jck pine krft pulps Ponderos pine ws redily cooked to produce bleching sulfte pulp tht ws sufficiently low in lignin content nd permngnte numbers nd sufficiently high in brightness fter one-stge blech test to indicte stisfctory bleching qulities with norml quntity of chlorine (tble 2) The dditionl mounts of chemicls used for producing the bleching pulps over those required for the krft-type pulps cused norml reduction in pulp yield nd in pulp strength nd n improvement in the chemicl purity of the pulps Conclusions Except for the lower chemicl requirements nd the lower yields of screening rejects in production of ponderos pine krft pulps, ponderos pine ws, ix, generl, very similr in sulfte-pulping chrcteristics nd in the strength of the pulps produced to jck pine, pulpwood of ccepted stisfctory qulity Report o

5 Tble 1--Chemicl Constituents of ponderos pine chips nd sulfte pulps Chemicl constituent Type of mteril produced in -- Chips : Pulp :Digestion o:digestion o:digestion o 2165X 29GY : 216X Lignin percent: 251 : 266 : 46 : 29 olocellulose do: 677 : : 956 Alph cellulose do: 45 : 538 : 781 ; 8 Totl pentosns do: 12 : 17 : 12 ; 68 Ash do, 5 : Alcohol-benzene extrct- : : bies do; 56 : : Ethyl ether extrctblesdo: 41 9 : ot wter extrctblesdo,: 29 Sodium hydroxide) extrctbles do The concentrtion of sodium hydroxide in wter solution ws 1 percent by weight Report o 8199

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