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COOKING BY CLOSED-TANK METHOD.
The old papers after handling, as previously noted, are run into large rotary boilers, together with milk of lime, and soda ash or caustic soda, depending on the particular mill practice, and after closing the boiler, live steam is introduced to a pressure of from 10 to 50 pounds, equal to a temperature of from 240° to 300° F., and the boiler is rotated. This cooking process is carried on from 8 to 16 hours, at the end of which time the pressure is relieved and the contents dumped into box trucks and run into washing engines, where the stock is defibered by the action of the beater roll, and the ink and dirt are removed by one or more cylinder washers. This washing process requires from 4 to 8 hours, depending upon the number of cylinder washers. After washing, the stock must be bleached with a chloride of lime solution and then run into draining vats, where the stock drains, and after rewashing by the introduction of water to free the stock from any remaining bleach the stock is ready to be put into beaters preparatory to remaking into paper. This draining process requires from four days to two weeks. The length of time required to drain is due to the necessity of removing any bleach that may remain, as bleach has an injurious effect on finished paper. The loss of fiber due to this process is from 25 to 50 per cent, depending on the care with which the operation is carried on and the quality of papers used.
COOKING BY THE OPEN-KETTLE PROCESS.
The principal difference between this method as compared with the closed-tank method is that the old papers are cooked in open tanks at atmospheric pressure equal to 212° F., and a solution of soda ash is used. The cooking operation is carried on from 10 to 16 hours, at the end of which time the stock is washed, bleached, and run into drainers, as in the first method described, with the same time requirements. The loss of fiber due to this process is from 20 to 40 per cent and is less than the first method, due to a decrease in both temperature and pressure, as well as a decrease in strength of chemicals used.
COOKING BY THE INCLOSED-ENGINE PROCESS.
In this process the old papers are cooked direct in a beating engine, fitted with a steam-tight cover, at a pressure of 5 pounds, equal to a temperature of 228° F. Soda ash is the chemical used to soften the paper and to form an emulsion with the fats of the ink. This method of cooking and defibering requires about four hours, at the end of which time the pulp is run into washing engines, where it is washed in from two to six hours, and, after bleaching, is run to drainers, as in the previous methods. The loss of fiber by this process is from 20 to 40 per cent, but the time saved is from 4 to 12 hours over either of the two previous methods.
It is a very well-known fact that any fibers that go to make up a sheet of paper may be very seriously injured by the action of high temperature, causing a weakening in the fiber and an actual loss in weight, due to fiber decomposition. In other words, an increase in temperature results in an increased fiber loss. In order to get the best results from recovering old papers, the process must be carried on at the lowest temperature with the weakest chemicals and with as little mechanical action as possible. In addition to these three requirements, the consideration of time required is also an important item. Any process which does not require the pulp to be bleached after washing is a saving in machinery, labor, time, chemicals, power, and space, and also a saving in fiber loss, as any bleaching solution is injurious to all paper fibers.
The new process for the recovery of old papers, as invented by Mr. 0. C. Winestock, of Perkinsville, Vt., was very carefully inspected, and several runs were made.
The method of making each demonstration was as follows: Fifteen pounds of paper were weighed out and soaked in hot water (about 110° F.) for a few minutes; the wet stock was then fed to the machine. After filling the machine with the required amount of hot water at from 160° to 170° F., the wet paper pulp and chemicals were added, the machine run until a sample drawn from the machine showed no small particles of paper not entirely defibered. The time required for this machine to reduce paper to a mass of individual fibers suspended in water and to separate the ink from the fiber, varied from 2 to 15 minutes, depending or the characteristics of the paper used.
The pulp, after being reduced in the machine, was run into a single-cylinder washer, where it remained for from one to three hours, when it was thoroughly washed free of any ink particles.
The pulp, after washing, is then ready for the paper-machine beater and does not require any bleaching whatever, nor does it require the addition of any new stock.
The estimated fiber loss is from 10 to 20 per cent, depending on quality of the stock, percentage of ash, and size.
The pulp was very carefully examined under the microscope to see if any particles of carbon remained; practically none were found. The fibers show no signs of injury either in regard to shortening or bruising, nor were the fine frayed-out ends of a well-beaten rag fiber destroyed. Any loss of fiber due to this process must come as a result of fiber passing through the wire of the cylinder washer. The operating temperature is too low to cause any appreciable fiber decomposition, also the chemicals used are too weak, and the mechanical action is such that there is very little or no loss from these causes.
Three kinds of paper were used for the demonstrations—"printed news," "printed Congressional Record," and printed "supply schedules" of the General Supply Committee. These three grades were selected for the reason that they include a wide range in grades, the “news" being 75 per cent ground wood and 25 per cent unbleached sulphite, the “Congressional Record” containing 100 per cent bleached sulphite, highly sized and calendered, and the “supply schedules” containing 90 per cent rag and 10 per cent bleached sulphite pulp. The following table shows the time required for handling each of the three lots of paper:
The lots of paper used were all more or less colored with coloring matter, it being necessary to use some blue and red coloring in order to get a white sheet of paper. This coloring matter was, of course, washed out during the process, along with ink, size, and filler, so that the color of the recovered stock was not an absolute match with the paper before going through the process, but there is no doubt that had the pulp been made back into paper, under the same conditions as when originally made, the resulting paper would have been an exact match. Any paper maker will readily understand this point and appreciate its full value.
It is a well-known fact that in recovering books and higher grade stock, the presence of any paper containing ground wood is shown by the paper turning a very darkbrown color, which can not be bleached out, and this paper tends to lower the value of the whole batch of recovered stock. The Winestock process absolutely does not discolor papers containing ground-wood pulp, thus making this process available for recovering old newspaper,
The machine is of such design that it could very readily be made in larger sizes--say, for example, one handling a charge of 500 pounds of old papers. The time of handling such sized charges would not be increased very materially, besides such sized machines would cut down labor, floor space, etc.
To sum up and compare this new process with the three processes, as previously described, shows the following advantages in favor of the new process: A great reduction in time required to recover, decrease in floor space, power, labor, and chemicals, a very much lower working temperature, and no bleaching or new stock required. Considering all these points, the fact of increased fiber yield becomes self-evident.
It is recommended that this process be installed for the purpose of converting the waste paper now sold as such into a wet stock called by the trade "wet sheets,” and sold as such.
All papers must be subjected to a recovery process for the purpose of defibering or deinking, or both, before the paper stock becomes available for remanufacture into paper. For this reason it becomes necessary to divide the Government waste paper into two general classes, viz, those papers available for remanufacturing into white or colored papers, and the remaining papers that are only available for remanufacturing into "wrappings," "boxboards," etc.
The first general class may be still further subdivided into the following grades:
No. 1 white bond and ledger shavings.
Book. Under this subdivision, the following tonnage is available for remanufacturing into high-grade white and colored papers.”
357.67 Colored writings (rag):
308. 15 Printed and used writings.
743. 83 Book.....
2, 478. 16 The balance, 1,748.38 tons, could go into a grade of remanufactured wrapping papers. It would be more advantageous to take this or most of this paper now in shape of wrapping paper, and assort for good pieces to be reused as wrapping and sold only as waste paper when unfit for reuse. This paper, when unfit för reuse as wrappers, may be reduced to pulp, but it is better not to have so great a difference in the grades at this pulping plant because this wrapping paper is a much inferior grade to the 3,964.17 tons before mentioned. It is suggested that this paper be sold as recommended under plan No. 1.
The cost of reducing this 3,964.17 tons by the Winestock process into wet sheets ready for shipment to and use by paper mills would be about $9 per ton. This figure has been computed by the expert from the Bureau of Standards, one of the members on the joint committee on waste paper, who has had practical experience in paper mills and is familiar with the Winestock process.
This $9 per ton includes estimated depreciation on plant and interest on investment.
The following table gives the estimated costs in connection with the pulping and other handling of this 3,964.17 tons: 3,964 tons of pulp, at $9 per ton..
$35, 677.53 3,964 tons (present cost of collections, and other handling).
22, 722. 64 Motor truck maintained, etc., as per plan No. 1.
3,000.00 Assorting 1,356.61 tons, at $1.25 per ton....
1, 695. 76
63, 095. 93
In order that this pulp stock may be delivered in the best condition to
paper manufacturers, it is necessary to leave with the pulp in shipping a quantity of water or moisture about equal in weight to the pulp stock. Except for the loss of material due to the process of reducing to pulp which amounts to about 15 per cent of the original quantity of waste paper, the shipping weight of this pulp would be twice the weight of the waste. Therefore the average cost of transportation at $2.40 per ton would be.....
16, 173. 79
Tons. 3,964. 17
Illustrated as follows:
Original weight of waste....
Weight of pulp stock..
3, 369. 54
Freight cost, at $2.40 per ton...
$16, 173. 79
79, 269. 72
The table following gives the estimated revenues from the sale of these wet sheets:
TABLE No. 3.
The 1,748.38 tons would bring, if sold as per plan No. 1...... .... $15, 680.97
1, 695. 76 Difference in freight rates as described in plan No. 1.... 1,356. 61
13, 072. 16 Net revenue from 1,748.38 tons...
2, 608. 81 Gross revenue from 3,964.17..
137, 719. 70 Total expense costs..
79, 269. 72
Net revenue from 3,964.17 tons....
Net proceeds under plan No. 2.....
61, 058. 79 The net proceeds of $61,058.79 shown under the above plan contemplates no change in cost of collecting and handling as compared with the present plan. These costs under the present plan as shown by Exhibit A are $32,742.43 against a revenue of $62,527.95, leaving net proceeds of $29,785.52 annually. The increased proceeds under plan No. 2 over the present plan, therefore, would amount to $31,273.27 annually.
The estimated cost of installing a pulping plant would be about $75,000. This amount would cover all possible contingencies.
In plan 3 it is thought that, as both plans No. 1 and No. 2 contemplate the selling of either the waste paper as such or the wet sheets as such to paper mills the shipping expense would be a large item, together with the numerous handlings of same, it would be better to remanufacture the waste into new paper in a Governmentowned plant. This paper could be used exclusively by the Government Printing Office, as that office is the largest buyer of paper in the Government service. It is believed that of all the plans described this plan should be followed, owing to the fact that the most favorable conditions would result therefrom.
The figures given throughout this plan are those compiled by the same representative of the Bureau of Standards as mentioned in Plan No. 2.
The 3,964.17 tons of the one class of paper mentioned in plan No 2 would reproduce 3,369.54 tons. This would be divided as follows:
The cost of manufacturing other than the cost of pulping as shown in plan No. 2 amounts to about $25 per ton. This amount includes depreciation and interest on the investment. 3,369.54 tons, at $25..
$84, 238. 50 Cost of collecting, handling, assorting, converting to pulp, etc., as shown in plan No. 2..
63, 095. 93
147, 334. 43 Value of paper shown above...
280, 223. 90 Net income from sale of 1,748.28 tons of waste paper, as shown in Table No. 3 of plan No. 2.....
2, 608. 81
282, 832. 71 Less costs as per above......
147, 334. 43 Net proceeds under plan No. 3..
135, 498. 28 The net proceeds of $135,498.28 shown under the above plan contemplate no change in cost of collecting and handling as compared with the present plan. These costs under the present plan as shown by Exhibit A are $32,742.43 against a revenue of $62,527.95, or net proceeds from the sales under the present plan of $29,785.52. The increased proceeds under plan No. 3 over the present plan, thereore, would amount to $105,712.76 annually.
The estimated cost for installation of plant for pulping, manufacturing paper, etc., is placed at a maximum of $600,000. This estimate covers cost of grounds, buildings, necessary machinery, etc.
A preliminary report on the subject of money pulp has been submitted to you under date of September 21, 1912. In this report it was recommended that a plan similar to plan No. 2 be followed. This commission expects within the next two months to submit a final report relative to money-paper pulp.
There is now being erected on the grounds of the Bureau of Standards, to be operated under its supervision, a complete commercial size defibering and deinking machine of the Winestock make. It is anticipated that this machine will be ready for operation during the first week of February, 1913, after which time additional practical tests will be made, and reports relative thereto will be duly submitted. Respectfully submitte 1.
FREDERICK A. CLEVELAND,