not yet sufficiently advanced to recommend this process1. On the other hand, viscose pulps made largely from wood, as well as cotton linters, have been made from pine sulphites and some work has been done on the use of bleached sulphate. In addition, birch and aspen have been used

commercially.

It would seem worth while, therefore, to test the principal native hardwoods as well as the leading plantation species, Insignis Pine, as a raw material for viscose pulp. If Insignis Pine sulphate can be prepared satisfactorily a small scale purification plant, operated in connection with the sulphate plant already proposed, might be the best solution for supplying Chile's present domestic requirements. If native hardwoods prove suitable the possibility of producing pulp for domestic and export markets could then be examined more intelligently.

Insulation and Hardboard

Insulation or fiberboard and hardboards have a great variety of uses and should find a large potential market in Chile, where they now make up less than ten percent of total paper consumption as against over one-third total paper consumption in the United States.

Fiberboards are made from a number of raw materials, including plant wastes such as straw, cornstalks, sugar cane bagasse, and extracted licorice root and various species of wood such as spruce, fir, pine, aspen, poplar, cottonwood, and willow. The wood species, in some cases, are used in the form of sawmill or resin extracted wood wastes. Most of these fiber materials can be used in making hardboard, though practically all such boards are now made from wood fiber. Recent research indicates that a hardboard can be made out of the residue from hydrolyzed wood from which most of the cellulose has been extracted in the preparation of alcohol by the modified Scholler or American process. The processes for reducing the material to pulp may be mechanical, or a combination of chemical and mechanical treatments. The mechanical processes include (1) the groundwood process identical to that used for making paper pulp, and (2) fiberization of the material in an attrition mill. When chemical softening is employed prior to fiberization the chipped material is partially digested in a dilute alkaline or neutral solution or subjected to the action of high temperature steam. Fiberizing of the softened material is done in attrition mills or brought about by blowing the softened chips from the treating vessel against a target. Since the chemical treatment is relatively mild, the yield of fiber obtained is 90 percent or more of the wood used.

Several types of forming and drying machines are employed, some of special design developed by the individual company, others designed for the purpose by equipment manufacturers.

Insulating boards are made in sheets of from 13 to 19 millimeters thick, weighing from 250 to 270 kilograms per cubic meter. Hardboards are made from the same materials but compressed to sheets 3 to 5 millimeters in thickness, weighing about 1,000 kilograms per cubic meter.

Investment costs will vary according to the process employed and the local conditions. The equipment required for pulp making will amount to 185 to 300 thousand pesos per ton of daily capacity. Forming, drying, pressing, and other auxiliary equipment will cost from 300 to 450 thousand pesos per ton. These estimates do not include power and steam plant facilities. The economic minimum size of board mill under conditions prevailing in Chile is not known. In the United States experience indicates the pulp mill should have capacity for production of at

1 War developments may, however, change this entire picture and result in the replacement of cotton linters by wood in the preparation of acetate pulps.

least 70 tons (metric) per 24 hours, from which approximately 200,000 square meters of insulating board, 19 mm. in thickness can be made. Chilean conditions might permit economical operation of smaller sized plants.

Considerable interest has been aroused in Chile to produce insulation and hardboard from sawmill waste and tests made with native species, including Canelo and Manio, are said to have been promising. The product in approximately 13 to 19 millimeter sizes could be used for lath or plaster base in frame houses, and for wall or ceiling coverings in auxiliary rooms and attics. Some contractors in Chile believe it would prove suitable as wall and ceiling material in place of plaster or wood in some types of dwellings. It would also find use in furniture, refrigerators, temporary structures, in poultry houses on farms, and in some kinds of packaging. Hardboard could also be used in kitchen and store fixtures, in toys, and in electrical and machine shop installations. The thicker size is suitable as insulating sheeting under the siding of frame houses. In this service it competes with low grade lumber. In the United States insulating and hardboards sell for about 16 to 18 pesos per square meter.

Insulating and hardboard, therefore, should find a ready market in Chile and if they can be prepared economically from sawmill waste, these products would offer a valuable outlet for the mill waste. The available processes and probable costs and returns under Chilean conditions warrant detailed investigation.

PLASTICS, ALCOHOL, AND PROTEIN FEED

Recent advances in the chemical conversion of wood have attracted world-wide attention. The transformation of wood into such commodities as artificial silk, sugar, plastics, alcohol, and cattle feed are not only remarkable performances to the laymen but develop more efficient use of wood as a raw material through elimination of some of the truly tremendous quantities of waste. Chemical conversion seems one of the most promising possibilities of using the sawdust pile and other waste, usually far in excess of plant fuel requirements, as well as bolt or log materials of smaller dimensions.

Nevertheless the possibilities are not as favorable or as farreaching as might be supposed. The technology of producing the materials mentioned no longer offers any great difficulties; the chemistry and mechanics of the processes evolved are clear. But sawdust and other wood waste is bulky and difficult to concentrate, and is economically feasible to operate often only under the most favorable of economic conditions, as under war pressures and shortages, or where the derived products are lacking or expensive, or where waste is particularly easy to obtain and handle in quantity. The price that can be paid for waste must be very low to make conversion operations economical.

The manufacture of plastics from wood and wood waste is one of the newer developments. The manufacture of Bakelite type of plastics, about one-half wood flour, one-half phenolic resins, is well known. More recently, chemists at the Forest Products Laboratory, Madison, Wisconsin, have developed a method of hydrolyzing wood to give a product showing utility as a semi-plastic filler to replace wood flour in phenol-formaldehyde resins. In this role the hydrolyzed wood effects a saving in phenol-formaldehyde resin. Because of marketing difficulties and other factors, this method is used to only a limited extent. Regardless of the process of production, however, it seems clear that the introduction of a wood based plastic industry in Chile would meet with

rather formidable difficulties growing out of the relatively small market available, the relatively large initial investment in plant and equipment, and shortage of skilled labor and technical knowledge. In the United States these factors have confined the preparation of the basic material, the molding powders, to a very few, large chemical concerns. Molders are dependent on these firms not only for their basic material but also to a considerable degree for technical service and guidance. Pending further developments, therefore, it would seem best for Chile not to attempt primary manufacture of plastics as an additional wood based industry.

The production of ethyl alcohol from wood is another process now well beyond the exploration stage as far as chemical and technological difficulties are concerned. Alcohol in quantity has been produced from wood in both Europe and the United States, in the latter under war conditions, and a large scale plant using the modified American process is now being built which may prove economic even after war demands lessen and price recessions occur. In Germany plants using 60 tons of wood per day with the Scholler process have proved economic. If the operation of plants using 60 to 100 tons of wood per day prove economic in Chile, an alcohol plant would integrate well with the medium to larger size mills recommended. A sawmill cutting 48 thousand board feet per 8-hour day, for example, furnishes 60 to 120 tons of sawdust and waste over fuel needs, depending on how much woods waste is used in addition to sawdust and mill scrap. This wood could be furnished at 40 to 45 pesos per ton for mill waste and 80 to 96 pesos, possibly less, per ton for woods waste under average conditions. These prices compare favorably with wood costs in the United States for similar material and could undoubtedly be lowered under better than average conditions. A 60-ton plant would produce annually up to 4 million liters from softwood, or 3 million liters from hardwood. This product should find a ready market. Some 2 million liters of ethyl alcohol at a price ranging from 3.18 to 7.30 pesos per liter have been used over the last several years for gasoline adulterant alone. If alcohol can be produced from wood at a reasonable price, in the neighborhood of 3 pesos per liter (which would compare favorably with ethyl alcohol and gasoline prices in the prewar period), it would prove a welcome addition to the raw material supply for Chilean industries. This would depend on how efficiently a small plant can be operated under Chilean conditions. The relatively small size of hardwood mills and the difficulty of concentrating large quantities of waste economically would definitely limit the size of operations.

1

On the other hand, some hardwood species might prove better for the production of carbohydrate or protein feeds. A high content carbohydrate cattle feed should find a ready market in Chile. Several methods have been used in Europe for the conversion of wood waste into cattle feed. The simplest method is a development of the pulping processes in Sweden where it was used to produce feed after the German occupation of Norway and Denmark closed off imports of hay and grain. The process consisted of overcooking of chips in the regular sulphite pulping process so that most of the cellulose was hydrolyzed. The cellulose became soft and capable of being used as roughage. The pulping liquor, which was rich in sugars, was concentrated and mixed with the soft pulp for feed. This process is not very efficient because so much of the sugars are destroyed in the process. About half the carbohydrate material becomes available as cattle feed. Cattle in Sweden lived on this syn

This discussion on cattle feed from wood waste based primarily on a memorandum by Harris of the Forest Products Laboratory, Madison, Wisconsin.

thetic feed for three winters and produced milk. equipment is used.

ars.

Standard pulping

A second method, which was developed in Sweden by Hagglund and commercialized in Germany as the Bergius-Hagglund saccharification process, is the most efficient of all processes for the production of sugIn this process wood chips, sawdust, or shavings are treated with hydrochloric acid gas and sufficient moisture under pressure so that 42 to 44 percent hydrochloric acid is produced at low temperatures on the wood. While at 20° to 30° C. the chips stand in this strong acid for 8 to 16 hours, which converts the cellulose into a sugar syrup. The hydrochloric acid is removed by evaporation under diminished pressure leaving a thick sugary mass containing lignin. This mass is mixed with a little lime to neutralize the remaining acid and then mixed with chopped straw for cattle feed. This process gives 60 to 65 percent yields of sugar from wood. The disadvantage of the process is that it must be carried out in stoneware equipment and, because of the large amounts of hydrochloric acid required, it is rather expensive. The sugar from this process is not fermentable.

A third process involves the treatment of chips, shavings, or sawdust at gradually increasing temperatures from 150° to 180° C. with successive batches of 0.5 percent sulfuric acid. This is the Scholler process, mentioned above, now commercialized in Germany. Plants have also been built in Finland, Italy, and Japan. Because of the lack of large sources of wood waste in one locality, the Germans developed a plant to use 60 tons (dry basis) of wood per day. They assumed that smaller plants could not operate economically in Germany.

The sugars from this process are in a dilute solution which must be evaporated to a syrup for use as cattle feed. The Germans have also experimented with the production of human food from this process. About half the sugars may be crystallized for edible glucose. The remainder may be fermented to produce alcohol or used to grow yeast for humans or stock. This process gives approximately 50 percent yields of sugar from wood.

A fourth process has been developed as far as the pilot-plant stage in Finland. This process uses successive treatments of chips, shavings, or sawdust with 1 to 5 percent sulfur dioxide at 180° C. over a period of about 16 hours. In other respects the process is similar to the Scholler process. It is possible that the American modification of the Scholler process could be operated economically in Chile for the production of sugars or yeast at sawmills producing 20 to 30 tons (dry basis) of wood waste. Such a plant, including a heating plant, should cost about 6,200,000 pesos and require about 20 men to operate on a 24-hour per day basis. The lignin produced will supply most of the fuel required.

For the production of yeast for high protein feed, the sugar solution from the modified Scholler process is diluted still further. Nitrogen in the form of ammonium salts and phosphates are added. Yeast such as Torula is introduced and air is pumped through the solution which promotes the growth of yeast. Very little alcohol is produced. A 20 to 24 percent yield of dry yeast containing 50 percent protein may be obtained from wood (dry basis). This yeast is in a very concentrated form and must be fed mixed with straw or other materials for cattle. It is being used as human food in Germany.

It should be possible to produce a carbohydrate food from wood which is 80 percent or more digestible by cows for about 1,240 pesos per ton (800 kg.) and high protein yeast 100 percent digestible, 50 percent protein for about 4,030 pesos per metric ton.

The larger saw mills in Chile may each have 20 to 30 tons (dry basis) or more, of wood waste per day. Plants with 20 to 30 tons of waste per day would provide about 15,000 tons of wood waste per 300-day

year and produce 7,500 tons of carbohydrate (80 percent digestible), or 6 million kilograms of carbohydrate food for cattle, hogs, or chickens. The wood-using industries in the large cities may provide sufficient wood waste for other plants. Those operating on hardwoods are better suited for the production of yeast because some of the sugars produced from hardwoods are not useful to higher animal organisms.

Accordingly it is recommended that experimental trials be made to determine the alcohol, carbohydrate and protein yields obtainable from leading Chilean species. If the results are promising, a further study should be made of the economic aspects of alcohol and protein feed production.

TREATING PLANT

The sections relating to ties and poles under national timber requirements, present and future, have emphasized that the growing shortage of Roble and rising price for ties and the proposed pole program under the projected electrification program, make the early installation of a treating plant advisable and justifiable. The advantage of properly applied preservative treatments, using creosote-coal-tar solutions or creosote-petroleum solutions as a means of prolonging the life of railroad ties and telephone and electric power poles, is well known. According to experience in the United States, non-durable species that give only a few years service without treatment will last from 20 to 30 years or more if properly creosoted and mechanically protected.

In a report made by the Norfolk & Western Railroad, it is stated from tests made at their treating plant that Coigue, Ulmo, and Tenio will take treatment very well. No doubt there are a number of other species that are satisfactorily treatable and have the other properties required of ties. Since treated ties may contain unlimited amounts of sapwood, they can be cut from smaller trees than is possible for untreated ties required to be all heartwood. Larger tree sections often produce two ties suitable for treatment that would yield only one allheartwood tie. It is estimated that the timber actually cut would produce 50 to 100 percent more ties with sapwood than of all-heartwood, and, as the treated ties would have a service life expectancy of over 20 years, the actual depletion of standing timber required to meet present demands might be reduced by 2/3 to 3/4.

The longer life, reduced volume of timber required, production from lower priced species and reduction in renewal expense means that it would be economical and highly desirable to use creosoted ties in preference to untreated Roble. Though Roble does not take treatment readily it is reasonable to believe that pressure treated Roble ties would give much better service than untreated. In the United States, though white oak does not take treatment readily, it has been found desirable to treat it because of the longer service life, treated ties on one railroad lasting 20 years as compared with 12 if untreated.

In the United States, as the percentage of treated ties in track increased, the average annual replacements by the principal railways decreased, as shown in table 33.