Spanish brown, Indian red, dry or moist, colcothar, dry oxide of iron-Rates of duty. 87 Colors and paints, * * * whether dry or mixed, or ground with 1883 1890 61 1894 48 * All other paints, colors, and pigments, whether dry or mixed, or All paints, colors, pigments, *** whether crude or dry or All paints, colors, pigments, * * * whether crude or dry or mixed, ** *Spanish brown, venetian red, Indian red, and colcothar or oxide of iron, not specially provided for in this section. COURT AND TREASURY DECISIONS. Rates of duty, specific and ad valorem. 25 per cent ad valorem. Do. Do. 30 per cent ad valorem. Do. 10 per cent ad va lorem. Oxides of iron in general use both as colors and as polishing powders were held dutiable under the provision in paragraph 479 of the act of 1883 for "polishing powders of every description, by whatever name known," and not under the provision in paragraph 87 for colors and paints. (Zucker, etc., Chemical Co. v. Magone, 37 Fed., 776.) Venetian red was classified as a dry paint and not as ochery earth under the act of 1890 (G. A. 629, T. D. 11346), but red earth, a calcareous earth colored by ferric oxides of a red color and similar in appearance to red hematites, was classified as ochery earth (G. A. 1880, T. D. 13608). Oxide of iron used to purify coal gas by abstracting the sulphur therefrom was classified as an unenumerated unmanufactured article under that act. (G. A. 4146, T. D. 19355.) Oxide of iron in the form of loose earth and declared to be in fact an Indian red in a crude condition was held to come within paragraph 58 of the act of 1897 as a crude pigment. (G. A. 4201, T. D. 19580.) A red pigment imported to be used as a color was held dutiable as a color rather than as an ochery earth or as an ocher. (Vandegrift v. United States, 107 Fed., 265.) Crocus, a product from the dross or residuum of burnt pyrites treated by a process to eliminate the sulphur and used properly as a polishing powder, but to a considerable extent as a painter's color, was held dutiable as a color and not as dross or residuum from burnt pyrites under the act of 1890. (Smith v. United States, 93 Fed., 194.) This case was followed in the classification of oxide of iron in the form of a ground hematite which was classified as a color and not as unwrought and unmanufactured earth under paragraph 93 of the act of 1897. (G. A. 5016, T. D. 23346.) Oxide of iron in its condition as taken from the ground without any preparation whatever, intended for use as a pigment, was classified under paragraph 55 of the act of 1913 at the 10 per cent rate. (T. D. 34390.) Tuscan red No. 4076 DX, claimed to be oxide of iron within paragraph 55, or pigment within paragraph 61 of the 1913 act, was returned by the chemist as containing about 10 per cent of coal-tar 35284-21-A-15- -7 coloring matter, some inert diluent, and the remainder iron oxide with a little moisture inherent in colors. The definition in the Oxford dictionary of the word "lake" was followed, and the merchandise held dutiable accordingly under paragraph 63 of the act of 1913. (Abstract 40363.) Tuscan red, a coal-tar color lake composed of oxide of iron and containing about 4 per cent of aniline color, was held dutiable under Group III of section 500 of the revenue act of September 8, 1916, at 30 per cent ad valorem, plus the special duty of 5 cents per pound imposed in section 501. (Abstracts 42413, 42464, and 43708.) appeal is pending in the Court of Customs Appeals from Abstract 43708 upon the question whether the special duty of 5 cents per pound accrued. (T. D. 38444.) (See also survey on Paints of all kinds, par. 63, infra.) LEAD PIGMENTS. An OXIDES OF LEAD-LITHARGE, RED LEAD, AND ORANGE MINERAL. [Par. 56, 25% ad val.] SUMMARY. The oxides of lead are less important pigments at the present time than they have been in the past, but they are used more largely in other industries. Litharge, the monoxide, which was formerly used as a coloring agent in yellow paint, is now used in the paint industry for the preparation of boiled linseed oil and to some extent in preservative paints. The chief consumption is in glass making and pottery manufacture. Litharge is the chief source of lead for the production of lead acetate and other lead salts and for many lead pigments, especially the chromates. There are numerous minor uses. Massicot is another variety of lead monoxide, differing only in physical properties from litharge. It is made almost exclusively for the manufacture of red lead. Red lead, lead tetroxide, is a very heavy orange-red pigment having great covering power and brilliancy. It has been largely used in preservative paints for structural steel. Like litharge it is also used in making glass. Orange mineral is a variety of red lead which has been prepared with special care. It is generally made from white lead whereas red lead is made from massicot which is prepared by the oxidation of molten metal. It is more expensive than red lead and is often stained with organic dyes and sold as artificial vermilion or "vermilionette." Both orange mineral and red lead are used in making rubber goods. The United States is a large producer and consumer of lead oxides. The output in 1916 was 121,548,000 pounds, valued at nearly $10,000,000. Over 62 per cent of the quantity and 60 per cent of the value was in the form of litharge; the remainder consisted almost wholly of red lead, as orange mineral is used in only minor amounts in this country. The chief localities of production are Pennsylvania, New York, Missouri, Illinois, Ohio, and California. For more than 20 years the litharge supply has come almost wholly from domestic sources. The prewar consumption (1910-14) was about 25,000 tons annually. There is a small production as a by-product of lead refining, but most of the output is made from pig lead. The consump tion of red lead during the five years ended December 31, 1914, was about 19,000 tons annually. Less than 5 per cent of this was imported. Nearly one-half of the 1,000 to 2,000 tons of orange mineral used annually in this period was imported. About 90 per cent of the weight and a large fraction of the value of litharge and red lead consists of metallic lead. Since the cost of metallic lead is generally greater in the United States than in European countries, the domestic producer of lead oxides is at a considerable disadvantage as regards the cost of his raw material. Fuel requirements are an important item, but the slightly cheaper fuel cost in this country does not offset the higher cost of lead. Labor is also a larger factor than it is in the manufacture of most paint products. Oxides of lead (litharge, red lead, and orange mineral)—Summary table. 5 Red lead valued at $3,681 imported free of duty for construction of vessels. GENERAL INFORMATION. PARAGRAPH 56, TARIFF ACT OF 1913. "Lead pigments: Litharge, orange mineral, red lead, white lead, and all pigments containing lead, dry or in pulp, and ground or mixed with oil or water, not specially provided for in this section, 25 per cent ad valorem." This survey deals only with the so-called "lead oxides" which comprise litharge, red lead, and orange mineral. White lead is discussed separately in this series. All other pigments containing lead and which are important commercially are provided for in other paragraphs of the tariff act.1 DESCRIPTION. There are several oxides of lead. Most of these, however, are of purely theoretical interest and the only ones that are important in the paint industry are litharge, the monoxide, and red lead and its modification, orange mineral, the tetroxide.2 Lead chromates, Par. 54. Vermilion red, containing lead but not containing quicksilver, Par. 59. Vermilionettes (red lead stained with eosine) are classified as "lakes." 2 Lead dioxide (PbO2) is used to some extent in the manufacture of aniline. 3 Litharge (PbO) is a reddish yellow powder. It is not so important as a pigment as it is for the preparation of "boiled linseed oil." It is used to some extent in the manufacture of preservative paints because it is basic (not acid) and resists corrosion. Litharge and linseed oil make a very hard cement-like film that withstands abrasion, but the litharge combines with the oil so fast that when used in mixed paints it tends to "liver" and saponify. A few black paints are held together by the use of litharge and, provided they are used within a month or two after they are made, serve their purpose perfectly. One of the largest uses of litharge is in the making of lead or flint' glass and in a large number of pottery glazes. It is also used as a flux in the assaying of gold and silver ores and, because of its ready solubility in acids, as a source of lead in the manufacture of many salts and compounds of lead (especially the acetate and nitrate). Litharge is frequently used as a pipe-joint cement, although not so satisfactory as red lead for this purpose. At one time litharge was used as a yellow pigment, but at the present time its chief function in the paint industry is as a drier. The rubber industry is another large consumer of litharge. Massicot is another variety of lead monoxide, differing from litharge only in physical properties. It has a lighter yellow shade than the latter and is prepared chiefly for the manufacture of red lead. Red lead is lead tetroxide (Pb,O,). Chemically it is regarded as a mixture of lead monoxide and peroxide (2PbO.PbO2), but commercial samples vary somewhat from this formula. It is a very heavy orange-red pigment, a little variable in color but having great covering power and brilliancy. Red lead was the first successful protective coat for structural iron and steel and is still preferred by some engineers. It is, however, a difficult pigment to use properly, since it must be applied very soon after mixing to avoid undue combination with the oil, and if it is not mixed with an inert base is very fatiguing to the painter that does the work. The high specific gravity of red lead makes it very heavy on the brush, and the workman is very likely to thin his paint so as to make it flow easier and thereby loses the protective quality of the coat. For this reason red lead is being mixed more and more with other pigments, especially graphite and iron oxides (and metallic paints), and has even been replaced in many instances by the latter. Asphaltum and other bituminous bases are also substituted frequently in outside work. Because of its active oxidizing effect with linseed oil, red lead is very extensively used as a lute in plumbing and gas fitting. A large use of red lead is for glass making. A minor consumption is in the manufacture of storage batteries. Orange mineral has the same chemical composition as red lead but differs in color and in its (lower) specific gravity. Strictly it is merely a very pure form of red lead, but it is manufactured from white lead, whereas red lead is produced from lead metal. Orange 5 1 Very pure litharge has the color of yellow ochre. The shade of commercial litharge varies, however, from lemon yellow to reddish yellow and on heating it becomes brownish red. 2 Stiffen the oil so that the paint can not be applied with a brush. 3 Toch. Chemistry and Technology of Paints. Van Nostrand. 1916. One proprietary brand (Dutch Boy Red Lead) will remain soft in oil, though nearly pure. 5 Generally the scum that collects on the surface of the wash waters used in levigating white lead. White lead was also used as a source of massicot when that pigment was important as a paint material (i. e. prior to the improvements in chrome vellows). mineral is the variety of red lead which is stained with eosine and sold as artificial vermilion or "vermilionette." It is valued by the depth of its orange shade. DOMESTIC PRODUCTION. The domestic output of lead oxides increased nearly 50 per cent from 1900 to 1910, and before the outbreak of the war increased another 50 per cent. The production of all classes of lead oxides in the United States in 1914 was practically 93,000,000 pounds, valued at something over $5,000,000. The increased use of structural steel through the war period (especially for ships and shipyards) and the heavy demands from the glass and rubber industries called for larger quantities of these oxides than had ever before been produced. The output in 1916 was 121,548,000 pounds, valued at nearly $10,000,000. Over 62 per cent of the quantity and 60 per cent of the value of the 1916 output of these oxides was in the form of litharge; the remainder was almost wholly red lead, orange mineral not being made in important quantities in this country. Raw materials. The fundamental raw material of all the lead oxides is, of course, metallic lead, which constitutes more than 90 per cent of the weight of these products and a considerable fraction of the value. A fraction of the litharge supply is derived as a byproduct of the desilverization of lead bullion, but it is made chiefly from market lead. Red lead is also made from the metal and to only a slight extent from unmarketable qualities of white lead. There is also a process for the production of red lead from litharge (instead of massicot) using nitrate of soda (converted to nitrite of soda).? Processes of manufacture.-Litharge and massicot are both made chiefly by the oxidation of melted lead in the air. The essential difference is that litharge is produced at a temperature sufficiently high to melt the lead monoxide (about 900° C.), whereas massicot is produced when the temperature is considerably below the melting point of the oxide. Litharge is frequently made in rotating drums made of cast iron and heated by an external fire. The drums have shelves or ribs. inside which pick up the melted lead and cause it to fall in thin films through a current of air which is drawn through by a fan. It is also produced in furnaces of the reverberatory type, but equipped with suitable arrangements for blowing air over the surface of the molten lead which, in effect, much resembles the cupelling operation in refining lead bullion and which furnishes part of the domestic litharge supply. The melted litharge from the furnace can be run over an iron plate and chilled with water. This produces yellow litharge in more or less lump form. Slow cooling favors the formation of a red, flaky variety. This is formed by allowing the melted litharge to collect in front of the furnace in cakes of from 1 to 1.5 tons in weight where it will cool very slowly. The inner part of the cake will swell up and form flakes of red litharge; the outer and 4 1 Compilations of Mineral Industry and of Geological Survey. Census data show only about two-thirds this amount. 2 See Holly's "Analysis of Paint and Varnish," p. 221. 3 Thorp. Outlines of Industrial Chemistry. MacMillan. 1916. 4 Hofman, H. O. Metallurgy of Lead. McGraw-Hill. 1918. |