Zinc oxide French process

A typical exterior acrylic paint formulation see Appendix A) was thickened with a commercial HASE thickener that contained 5.23 meq/g of carboxylic acid functionality (4). This thickener was modified with 1 to 25 lb (1 lb = 0.4536 kg) of zinc oxide (French process) in the mill base in one set of paints and with post-added zinc ammonium complex such as acetate, carbonate, bicarbonate, or glycinate in another set of paints. 

Zinc oxide (French process) 5.5 White — Neutralizes film acids, renders water noncor-... 

Metal Oxides. Zinc oxide is the most effective metal oxide. French-process-type zinc oxide, which is low in lead content, is incorporated into the latex as a dispersion. Zinc oxide serves three main functions (1) promotes cure (2) improves aging, heat, and... 

Historically, ZnO is an older pigment than Ti02. In France, the industrial production of zinc oxide started in 1840. In the French process, zinc... 

Zinc oxide is made either by the oxidation of the metal in oxygen (the indirect, IP, or French process), by the direct decomposition of zinc ores in air (the direct or American process) or by the thermal decomposition of zinc salts (TD zinc oxide). IP zinc oxides differ from TD zinc oxides in that their surfaces do not contain absorbed water. Also, whereas TD zinc oxide reacts with plain eugenol, IP zinc oxide hardly reacts unless activated by an acetic add or zinc acetate accelerator (Table 9.2). 

An activator in rubber compounds containing organic accelerators. In polychloroprene, zinc oxide is considered to be the accelerator rather than the activator. The use of zinc oxide as a reinforcing agent and as a white colouring agent is obsolescent. Zinc oxide is manufactured by either the French (or indirect) process or by the American (or direct) process. It can be used as a filler to impart high thermal conductivity. 

American Also known as the Wetherill process, and the Direct process. A process for making zinc oxide, in the form of a white pigment, from a zinc oxide ore. The ore is usually franklinite, which is predominately ZnFe204. The ore is mixed with coal and heated in a furnace to approximately 1,000°C, forming zinc vapor in a reducing atmosphere. The vapors pass to a second chamber in which they are oxidized with air, forming zinc oxide and carbon dioxide. See also French. 

Indirect An alternative name for the French process for making zinc oxide. 

Indirect sulfonating reagents, 23 522-523t Indirect vacuum gauges, 20 657 Indirect (French) zinc oxide process, 26 612-613 Indisan, 24 498... 

Zinc oxide is obtained as an intermediate in recovering zinc from minerals (See Zinc, Recovery). The oxide is prepared by vaporizing zinc metal and oxidation of the zinc vapors with preheated air (French process). The oxide can be produced by other processes. Another method involves roasting franklinite and other ores with coal and then oxidizing the product in air. 

Zinc oxide [1314-33-2], ZnO, Mr 81.38, was formerly used only as a white pigment, and was named zinc white (C.I. Pigment White 4), Chinese white, or flowers of zinc. The term zinc white now denotes zinc oxide produced by the combustion of zinc metal according to the indirect or French process. 

Indirect or French Process. The zinc is boiled, and the resulting vapor is oxidized by combustion in air under defined conditions. The crystallographic and physical properties of the ZnO can be controlled by adjustment of the combustion conditions (e.g., flame turbulence and air excess). The chemical composition of the ZnO is solely a function of the composition of the zinc vapor. 

In the indirect French process, metallurgically refined zinc metal is boiled and the generated vapors combust with air to form zinc oxide. Metallic zinc is the starting material of this latter process, making it more expensive than the American one. The French process is the preferred production method, however, because it yields a purer product. Volatile metals, such as lead and cadmium, are again the main impurities that can be found in zinc white. Complex purification methods, such as fractional distillation, have been devised to reduce the amount of these impurities to acceptable levels. 

ZnO powder is produced from the combustion of vapors coming from the distillation of metallic zinc according to the so-called French process or dry process. Using vapors coming from fractionated distillation, extra-pure oxide powders are produced, as illustrated from the chemical analysis data of two kinds of powder produced by two different companies ... 

The term zinc white now denotes zinc oxide produced by the combustion of zinc metal according to the indirect or French process. 

Indirect (French) Process. Zinc metal vapor for burning is produced in several ways, one of which involves horizontal retorts. Since all the vapor is burned in a combustion chamber, the purity of the oxide depends on that of the zinc feed. Oxide of the highest purity requires special high grade zinc and less-pure products are made by blending in Prime Western and even scrap zinc. 

In the manufacture of zinc white by the French process, metallic zinc is melted, evaporated and oxidized in the vapor state to zinc oxide with air. If the starting material is insufficiently pure, the zinc has to be purified by evaporation and condensation prior to the oxidation step. The size and shape of the zinc oxide crystals can be controlled by the oxidation conditions. After combustion the ZnO is precipitated from the ZnO/air mixture in settling chambers, in which classification of the zinc oxide particles takes place according to their size. 

The raw materials for the manufacture of zinc oxide by the American process are roasted ores, concentrates of zinc ores or more recently zinc hydroxide or zinc carbonate from the processing of scrap. These are reduced with coal and directly reoxidized to ZnO in the same reaction chamber. The purity of the zinc oxide is normally somewhat inferior to that from the French process. Grades of various purities can be produced by fractionation. 

Derivation (1) Oxidation of vaporized pure zinc (French process), (2) roasting of zinc oxide ore (franklinite) with coal and subsequent oxidation with air, (3) similar treatment starting with other ores, (4) oxidation of vapor-fractionated die castings. 

NanoTek zinc oxide - nanoparticle size zinc oxide manufactured by physical vapor synthesis process Societe des Blancs de Zinc de la Mediterranee, Marseille, France Cachet Or - French process zinc oxide Zinc Corporation of America, Monaca, PA, USA Kadox - French process zinc oxide... 

Zinc oxide is produced either by the French or by the American process. Both processes are pyrometallurgical techniques in which the metal in a vapor state reacts with oxygen, forming zinc oxide. The difference between the methods is in the raw material used for the synthesis. In the French process, pure metal is evaporated, and the final product is as pure as the metal used for its production. In the American process, zinc vapor is obtained directly from an ore by burning it as a mixture with coal or in an electrothermic process where electric current provides the heat. More recently, a new method, somewhat similar to the French process, was introduced by Nanophase Technologies Corporation who patented a physical vapor synthesis process in which zinc metal is vaporized. The vapor is rapidly cooled in the presence of oxygen, causing nucleation and condensation of nanoparticle size zinc oxide. The particles are non-porous and free of contamination. 

Figure 2.74 shows the morphology of nanoparticle size zinc oxide which can be compared with zinc oxide obtained in French process (Figure 2.75). 

The purest grades of zinc oxide from the French process contain more than 99.99% of ZnO. The purity of zinc oxide is essential in many applications because ZnO is a photochemically active material and impurities may severely affect its properties. Zinc oxide has found many applications due to its photochemical... 

Zinc Oxide. Rowers of zinc philosopher s wool zinc white C.l. Pigment White 4 C.l. 77947. OZn mol wt 81.38. Zn 80.34%, O 19.66%. ZnO. Occurs as the mineral zincite. Prepd by vaporization of metallic zinc and oxidation of the vapors with preheated air (French process) also from franklinite, (American process) or from zinc sulfide Faith, Keyes Clark s Industrial Chemicals. F. A. Lowenheim. M. K. Moran, Eds. (Wiley-In terscience. New York, 4th ed 1975) pp 882-888. Purification Depew, U.S. pat. 2,372,367 (1945 to American Zinc, Lead Smelting). The medicinal grade contains 99.5% or more ZnO technical grades contain 90-99% ZnO and a few tenths of 1% of lead. See also Colour Index vol, 4 (3rd ed., 1971) p 4687. 

White or yellowish -white, odorless powder. Hexagonal crystals d 5.67. Also reported as dj 5.607. Sublimes at normal pressure. nD 2.0041, 2.O203- American process zinc oxide pH 6.95. French process zinc oxide pH 7,37, Practically insol in water sol in dil acetic or mineral acids, ammonia, ammonium carbonate, fixed alkali hydroxide solns. 

CHEMICAL PROPERTIES noncombustible solid gradually absorbs carbon dioxide upon exposure to air reacts with hydrochloric acid to produce zinc chloride reacts with sulfuric acid to produce zinc sulfate, and it reacts with carbon monoxide or hydrogen to produce elemental zinc reacts lowly with fatty acids in oils and fats to produce lumpy masses of zinc oleate, stearate, etc. forms cement-like products when mixed with a strong solution of zinc chloride or with phosphoric acid, owing to the formation of oxy-salts hydrogen peroxide is produced when ointments containing zinc oxide and water are melted and exposed to UV light FP (NA) LFL/UFL (NA) AT (NA) HC (NA) HF (-350.5 kJ/mol crystal at 25°C) pH (6.95 American process zinc oxide, 7.37 French process zinc oxide). 

Chem. Descrip. French process Zinc oxide... 

Chem. Descrip. French process zinc oxide CAS 1314-13-2 EINECS/ELINCS 215-222-5 Uses Pigment for interior architectural all d enamels, anticorrosive primers... 

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