SU77406A1 - The method of obtaining yellow iron oxide pigments - Google Patents

Description

The invention relates to the preparation of pigments having widespread use in the paint industry.

Iron oxide pigments are the most important inorganic pigments, as they are made from affordable and cheap raw materials and have very high low-tech properties and a wide variety of colors (yellow, red, brown, black) and shades. These pigments are produced in small quantities, and only one red, due to the lack of developed methods for producing iron oxide pigments.

Adding to the solution of the iron salt a small amount of iron oxide hydrate — germs upon receipt of pigments — improves the color of the resulting precipitate.

The exceptional effect on the color and low-technical properties of iron oxide pigments obtained in the presence of nuclei has the properties of the latter.

To obtain a light-colored iron oxide pigment and excellent low-tech properties

32 Svoz. Issue 2, Part I. 1950

Only hydrates and iron oxides belonging to the modification a-yes and possessing active properties can be used as nuclei.

The latter are obtained only when operating under certain conditions, the deviation from which, sometimes even small, leads to a change in the properties of the hydrate-modification or activity, which drastically reduces or completely eliminates the germinal properties of the hydrate.

According to the proposed method, it is necessary to precipitate iron oxide salt (ferrous sulfate) ammonium ammonia and subsequent oxidation of the resulting iron oxide hydrate to obtain iron oxide hydrates, which have the best excess of iron salt solution (iron sulfate) at low temperatures (" below 40 ° C) by a slow current of air or a solution of bertolet salt.

The proposed method for producing iron oxide pigments is as follows: a germ in an amount of about 10-12%,

497 on Fe with respect to the iron oxide salt, is added to the iron oxide salt solution in which iron waste is placed (iron chips, scrap iron, tin waste, etc.), and air is blown through the whole mass at a temperature of 60-70 °. A very intense oxidation of metallic iron proceeds and a rich, light yellow precipitate forms. The resulting pigment has very high low-tech properties and very clean and bright color. The hiding power of the pigments is equal to: SY. 10-12 e / l2, i.e., the highest for the color pigments; the intensity is equal to the lead crown, i.e., the highest for yellow pigments. The resulting pigment in most paint and varnish compositions (oil nitro-enamels, oil paints) can replace lead crowns. The yellow pigments obtained by the proposed method, during calcination, form red iron oxide pigments of a very strong and pure color. Formulation of germ preparation 1) Iron vitriol (FeSOi. THNO) Technical ammonia, based on gas. Solution concentration. . Bertoletov salt .... Oka sleniya at a temperature of 2) Same as B p. 1, but oxidation is carried out with a weak current of air at a temperature of L5-20 ° for 18-20 hours. 2.75 kg 20-25% 20-22 °) Iron vitriol (FeSO, 7H2O) 54 kg Technical ammonia, based on 3.2 kg Concentration of solutions. . 15-20% Bertoletov salt .... 2.0 kg Oxidation at a temperature of 20-25 °) Same as item 3, but oxidation is conducted weakly. air flow. Pigment preparation recipe 70-120 kg Ferrous sulfate Metallic iron 200-ZOO kg (miscellaneous waste) 50-100% of Germ. . . . The specified amount of oxidation for 20-24 hours. at a temperature of 62-66 °. The subject matter of the invention is 1. A method of producing yellow geo-oxide pigments by oxidizing metallic iron with oxygen in air in an iron salt solution and in the presence of nuclei, characterized in that active hydrates of iron oxide a-modification are used as nuclei. 2. A method according to claim 1, wherein the iron oxide hydrate for the embryo is obtained by oxidation at temperatures below 40 ° iron hydroxide precipitated by ammonia from iron oxide salts. 3. A method according to claim 2, characterized in that the oxidation of iron oxide hydrate at a temperature not higher than 40 ° is carried out in the presence of an excess of iron salt, either with a slow air flow or with a potassium salt.