SU763411A1 - Method of producing yellow ferric oxide pigment - Google Patents

Description

The invention relates to the production of yellow iron oxide pigments applied to paint, leather, construction and other industries. A known method for producing yellow iron oxide pigment by oxidizing a weakly acidic solution of iron sulfate with oxygen in the air when heated in the presence of specially prepared iron oxide nuclei and metallic iron. However, this method requires the consumption of metallic iron to neutralize excess sulfuric acid. In addition, this process is accompanied by the formation of significant uterine effluents, with sodhersside of iron sulfate, the utilization of which is associated with considerable difficulties. There is also known a method for producing yellow and iron oxide pigments. According to KOTOpoN y, an additive of aluminum sulfate in an amount of 0.5-10% based on aluminum to iron is added to the prepared ferrous sulfate solution, then the solution is treated with ammonia and oxidized with air. germ, after which the pigment particles are grown from the resulting reaction suspension by blowing the latter with an air-ammonia mixture when heated, the resulting pigment precipitate is then separated from the mother liquor 2 The disadvantage of this method is the low pigment concentration in the final suspension. In addition, the low concentration of the mother liquor in ammonium sulfate, in the order of 50-60 g / l, does not allow for a sufficiently economical utilization of it in order to obtain the appropriate fertilizer from it. The purpose of the invention is to increase the concentration of yellow iron-iron pigment in the final suspension and to ensure the use of mother liquor for the production of ammonium sulfate. This goal is achieved by the described method of obtaining yellow iron oxide pigment by preparing the ferrous sulfate solution, precipitating the embryo in it by treating it with ammonia and air oxidation, introducing it into,; . ;. .

 . g.

nuyu. The reaction suspension is the addition of aluminum sulfate in an amount of 0.050.2% by weight of iron in the initial solution, followed by the growth of pigment particles by blowing the suspension with an air-ammonia mixture while heating and separating the resulting pigment precipitate from the mother liquor.

The difference of the method is that the addition of aluminum sulfate is introduced into the reaction suspension containing the nuclei and dissolved ferrous sulfate.

In this case, aluminum sulfate is used in an amount of 0.05-0.2% by weight of iron in the initial solution.

The proposed method provides an increase in the pigment concentration in the final suspension to 120 g / l with an ammonium sulfate concentration in the mother solution up to 165 g / l, which allows the latter to be used for efficient processing for fertilizers.

Example. An iron sulphate solution with a concentration of 240 g / l is loaded into a reactor with a working capacity of 2 m, after which water is added until 830 l of 80 g / l FeSOv solution is added. The solution is stirred with air and poured into it a 25% aqueous solution of ammonia in an amount of 92.8 liters, sufficient to precipitate 50% of iron. Compressed air is blown through the suspension to oxidize until the color of the precipitate changes from dark blue-green to pale yellow. When the pH of the suspension is in the order of 3.5-4.0, the oxidation process is terminated.

A strong solution of iron sulfate concentration of 240 g / l to a volume of 2 m and a total concentration of FeSO about 150 g / l is added to the obtained germinal suspension. Then, 2.3 kg of aluminum sulfate A6j (SO) j18 is loaded into the suspension from the calculation of the content of AI in the finished product to 0.06% of the iron content and the suspension is heated to 80 ° C.

Compressed air is blown through the heated slurry at a rate of oxidation, maintaining the pH in the range of 3-4 by adding to a cart, / /. .:

spirit of ammonia gas. During the synthesis process, the level of the solution is maintained by periodically adding an solution of ferrous sulfate and then water. In this case, the solution of ferrous sulfate is served until its total amount in the process of pigment synthesis is 420 kg, after which the solution is compensated with water supply. The synthesis process is continued until the concentration of the pigment in the suspension is 120 g / l. The pigment is then separated from the pure yellow colored mother liquor, in which the concentration of ammonium sulfate is 165 g / l.

Claims (2)

1. A method for producing a yellow iron oxide pigment, which includes preparing a ferrous sulfate solution, precipitating embryos in it by treating with ammonia and air oxidation, then growing the pigment particles from the resulting reaction suspension by blowing an air-ammonia mixture while heating, adding aluminum sulfate and separating the resulting suspension pigment precipitation from the mother liquor, characterized in that, in order to increase the pigment concentration in the final suspension and the use of mother liquor for the production of ammonium sulfate, the addition of aluminum sulfate is introduced into the reaction suspension containing the nuclei in dissolved ferrous sulfate. 2. Method POP.1, characterized in that aluminum sulphate is used in an amount of 0.05-0.2% by weight of iron in the initial solution. Sources of information taken into account in the examination 1. Belenky EF, Riskin I. V. Chemistry and technology pigments, L. Chemistry, 1974, p. 371-380. 2. Japanese Patent W 38-26278, cl. 24 A 4, 11.05.63.