lime is completely chlorinated. The temperature of the lime during chlorination should be kept below 45° C. It is possible to make a stronger bleaching powder during cold weather than in warm weather. After chlorination the powder is packed in drums or wooden barrels for shipment. In France it is the custom to sift the bleaching powder before packing. During this operation the bleach loses in strength, but the resulting product will keep longer and is much better for shipment. The yield of bleaching powder obtained is, in good practice, one and a half times the quantity of lime used. Hasenclever, an English chemist, overcame serious engineering difficulties in building an apparatus for carrying out this process in a continuous manner. His apparatus is, in essentials, a series of continuous conveyors; the lime is fed into the top while the chlorine is drawn in at the bottom in a direction opposite to the lime. We have no knowledge that this process is being used in the United States. The foreign and domestic methods of manufacture are not dissimilar, the primary difference being the method used in the production of the chlorine. In England and France the Deacon and Weldon processes have been generally used, although recently the electrolytic process has gained considerable headway. Both of these processes obtain chlorine by the oxidation of hydrochloric acid, which has been produced from salt. The Deacon process oxidizes the hydrochloric acid by means of air, while the Weldon process uses manganese dioxide which is regenerated and used again. Both are more complicated than the electrolytic process. In Germany the chlorine is obtained. from the electrolysis of solutions of sodium or potassium chlorides. Skilled labor in the manufacturing of bleaching powder is not a necessity so long as the plant is under the supervision of a competent chemist. Since the manufacture of bleaching powder in this country is dependent on electricity for the production of chlorine, it naturally follows that Niagara Falls should be a center for this industry. However, it is not confined to this locality, as plants in other parts of the country have been operated successfully on electricity generated from steam power. Important uses.-Bleaching powder, as its name indicates, is essentially a bleaching agent. It is used for the bleaching of wood pulp and other paper stocks, cotton and linen fabrics, cotton for the manufacture of gun cotton, and as a bleaching agent in laundries. It is also used in the manufacture of other chemicals, principally chloroform; for the purification of public water supplies; and as a disinfectant, deodorant and germicide. For domestic uses it is sold in small tin cans under the name of chloride of lime. Substitutes and rival commodities.-(a) Liquid bleach: This is a solution of calcium hypochlorite and chloride produced by passing chlorine into a solution of lime, commonly called "milk of lime." It is easier to make than bleaching powder and is usually produced at the place where it is to be consumed. The numerous paper and pulp mills in this country which make their own bleach furnish instances of this practice. There is a marked tendency for the large consumers of bleaching powder to install electrolytic chlorine plants and to produce their own bleach in liquid form. This tendency has been accentuated by the war demands on chlorine. (b) Liquid chlorine: Since about 1910 this article has become a rival of bleaching powder and is fast displacing it in the purification of water supplies. It is also being used for bleaching in textile mills. It is doubtful whether liquid chlorine will take the place of bleaching powder for export, owing to the necessary back shipment of the containers. (c) Hypochlorites of sodium and potassium: Owing to the high cost of potassium salts, the hypochlorite of sodium is usually made in this country. It is produced by a special electrolytic cell at the place of consumption, or it is made from bleaching powder by treatment with soda ash. Sodium hypochlorite is preferred to lime bleach in the bleaching of cotton and linen because it gives a clear solution and because the salts formed during the bleaching are easily removed from the fabric by washing. For this reason it is used extensively in laundries and textile mills. History of the industry.-Bleaching powder was invented in 1799 by Tennant, an Englishman. It was first made in the same year by the St. Rollox Works (England) and sold at £140 (about $700) per ton. The early development of the manufacture of this commercial product took place in England. It was not until 1897, however, after the passage of the tariff act of 1897, which placed a duty of onefifth cent per pound on bleaching powder, that its manufacture was undertaken on a commercial scale in the United States. The plant of the Dow Chemical Co. at Midland, Mich., and of the Castner Electrolytic Alkali Co., at Niagara Falls, N. Y., were both started in the latter part of 1897. The industry developed rapidly from that time on. As shown by the Census of Manufactures, the production increased from 21,958,000 pounds valued at $462,949 in 1899 to 310,380,000 pounds valued at $2,916,225 in 1914. As the American industry expanded to meet our own demands, there was a gradual decline in imports. Not until about 1908, however, was there a marked falling off in imports. This probably was due to an increase in consumption with imported bleaching powder about holding its own. Just prior to the outbreak of the war the imports of bleaching powder had fallen off 30,000,000 to 40,000,000 pounds; they have since become negligible. During the 1918 fiscal year only 4,285 pounds were imported. The importation of bleaching powder was restricted by the Shipping Board and the War Industries Board. The reason for this restriction was that Europe was the only source of imports and we were then shipping large quantities of bleaching powder and other chlorine products to Europe. Therefore, importation of bleaching powder from Europe was a waste of shipping space. The fact that we are now supplying our own consumption, and that during the 1918 fiscal year we exported over 13,000,000 pounds is sufficient indication of the development of the bleaching powder industry in the United States. Largest producers. Although figures on the actual production of bleaching powder in the United Kingdom and Germany are not available, it is evident that these two countries along with the United States are the largest producers of bleaching powder. The import statistics show that 70 to 80 per cent of the bleaching powder imported into the United States came from the United Kingdom and the greater part of the remainder from Germany. The following table compiled from official publications of Germany1 and the United Kingdom 2 is indicative of the status of the industry in these countries: 1 Includes bleaching powder, bleaching lyes, and peroxides of hydrogen and barium. Lunge states that the production of bleaching powder in England was 125,000 tons in 1909 with the production decreasing. The production in the United States in 1914 was 150,000 tons. This information seems to indicate that at this time the United States was producing as much bleaching powder as any other country. The bleaching powder industry expanded greatly during the war as shown by the following table. The exports of this commodity from Japan in 1917 were nearly seven times the prewar exports (1913). Prior to 1916 over 80 per cent of the exports were to China; during 1916 and 1917 British India took over 50 per cent of the exports. a Compiled from the Annual Return of the Foreign Trade of the Empire of Japan. b Included in all others. 1 Italy, during the years 1909 to 1913, inclusive, produced about 10,000 short tons of bleaching powder per annum. Special Agents Series No. 65, Chemical Industries of Belgium, Netherlands, Norway, and Sweden, by Thomas H. Norton, Bureau of Foreign and Domestic Commerce, contains information on the bleaching-powder situation in these countries. The annual production in Belgium exceeds 6,000 tons. The other three countries are dependent on foreign countries for their supplies. COMPETITIVE CONDITIONS. Bleaching powder and the electrolytic alkali industry.-Bleaching powder has been one of the chief marketable forms of chlorine gas, which is a joint product of the electrolytic alkali industry, the other product being caustic soda. The electrolytic process necessarily produces caustic soda and chlorine in chemically equivalent amounts, which are approximately equal. The chlorine in turn will produce roughly two and one-half times as much bleaching powder in comparison with the caustic soda produced. On the other hand, the demand for caustic soda is far in excess of the demand for bleaching powder and other chlorine products. Therefore the limit to the amount of caustic soda which can be produced electrolytically is determined by the amount of chlorine (bleaching powder and other products) which can be disposed of. In an effort to supply a greater portion of the large and profitable market for caustic soda, there has been a tendency on the part of the electrolytic alkali industry to overproduce chlorine or bleach. The result has been that prices for chlorine and bleaching powder have ruled so low that manufacturers claim that there has been very little if any profit in this end of the business. The prewar price of bleaching powder was practically constant at about $25 per ton, making it one of the cheapest chemical products. Effect of the war on the electrolytic industry.-The war produced a large, although temporary, increase in the demand for chlorine. There are a number of important substances used in poison-gas warfare which require chlorine in their manufacture. Three of these substances which were used in the greatest quantities were chlorine gas itself, phosgene, and mustard gas. Even before the entrance of the United States into the war this demand caused a large increase in the capacity of the existing chlorine plants. The estimated requirements, however, became so great and the prospects of disposing of the increased output when peace came were so small that private concerns were unwilling sufficiently to enlarge their plants on terms acceptable to the Government. The Government, therefore, erected a plant to supply a large part of the increased demand due to our entrance into the war at Edgewood Arsenal, Md. This plant has a capacity of 100 tons of chlorine gas per day. The output of chlorine during 1918 was about three times the output during 1914. The war undoubtedly caused substantial increased productive capacity in England, France, and Germany. As a result of this increased capacity to meet war demands, it is expected that keen competition will result. This competition will be sharper in bleaching powder and other chlorine products than in caustic soda. 1 From Annuario Statistico Italiano. The war demands for chlorine made it necessary for the Government to control the distribution of all chlorine products, including bleaching powder. In addition, restrictions were placed on the use of bleaching powder by the paper and pulp mills. Foreign competition.-Germany in the past has interwoven her chlorine industry with her potash industry, which has monopolized the world's markets. Much chloride of potash is treated electrolytically in Germany for the production of caustic potash; the chlorine, which is produced simultaneously, is charged against bleaching powder practically free of cost, since the value of the caustic potash is sufficient to cover all the cost of manufacture of both the caustic potash and chlorine and still leave a large profit. This cheap source of chlorine is largely responsible for the rapid rise of the manufacture of bleaching powder and chlorine products in Germany. Germany, prior to the war, had increased her exports of bleaching materials until they were equal in quantity to the exports of bleaching powder from the United Kingdom. The firms in England and France which use the Deacon and Weldon processes are apparently at a disadvantage in the production. of bleaching powder, since these processes are more complicated and require more attention than the electrolytic process. Although comparative cost figures are not available, the Deacon and Weldon processes appear to be more expensive, since the electrolytic process. is gradually being installed in England and France. Since the signing of the armistice marked progress has been made in the establishment of electrolytic chlorine plants in Europe, particularly in France. Germany and England, prior to the war, controlled the export trade in bleaching powder, while in the United States the industry had developed until we were supplying the larger portion of our consumption. The war forced the immediate withdrawal of Germany and later of England from the export trade in this article. Thus the foreign trade of these two countries was thrown open to the United States. This country, by increased production, has been able to supply its own demands and to develop an export trade. During the fiscal year 1918 we exported some 6,000 short tons of bleaching powder. C With normal competitive conditions restored we may expect a determined effort on the part of England and Germany to regain. this trade. This will undoubtedly result in a price-cutting war on the United States trade in this commodity. Our chief advantage in this competition will be our cheap power for electrolysis, but whether this will offset the advantages of cheaper labor in England and the cheap source of chlorine in Germany is a question. Production of bleaching powder in United States.1 1 Listed as hypochlorites, chiefly bleaching powder and chloride of lime. $462,949 535, 835 1,786, 846 2,916, 225 |