RU1784625C - Process for producing red iron-containing pigment - Google Patents

Abstract

SUMMARY OF THE INVENTION: Red mud - alumina production waste is mixed with a pyrite cinder in a ratio of 1: 1-3 in the presence of phosphoric acid in an amount of 0.8-1.2 wt.% P20s to Pb20z. calcine the mixture at 700-800 ° C, grind and the product is further classified, washed from water-soluble substances, filtered and dried. Pigment characteristics: oil absorption of 30.2-31.9 g / 100 g of pigment, hiding power of 10.6-11.2 g / m2, dispersibility of 25-32 microns. 2 tab.

Description

The invention relates to a technology for producing red iron-containing pigment used in the paint and varnish, paper and rubber industries, as well as in the production of plastics and leather.

A known method for producing red iron-containing pigment by dehydration of iron sulfate heptahydrate (H), pre-mixed with iron (II) sulfate monohydrate in a 1: 1 ratio in a rotary drum furnace at a temperature of 550-600 ° C, calcination of iron (II) sulfate monohydrate with the addition of 4.0-5.0% reducing agent in a rotary drum furnace at a temperature of 700-850 ° C. The resulting product is washed from water-soluble substances, crushed in a ball mill, classified, filtered and dried.

The specified method has significant drawbacks: a complex technological scheme, a high consumption of raw materials, a significant amount of difficult to utilize sulfur-containing gases.

A known method of producing brown iron-containing pigment using pyrite cinder by grinding, mixing with mulma - waste production of acetone, taken in the amount of 57-65% by weight of the mixture, followed by processing the mixture with 38-42% sulfuric acid in a mass ratio of acid and dry mixture of 1.5-2.0: 1 and calcination of the obtained product at 875-925 ° C.

This method is complex, contributes to the formation of a large amount of sulfate effluents and harmful sulfur-containing gases.

Closest to the invention is a method for producing a red iron-containing pigment from red mud - a waste of Sb & b & 18Г пШ $ её№Г 1 by mixing it with phosphomel and calcining

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mixtures with a mass ratio of (5-70) :( 30-95).

This pigment has a low oil absorption, but gives poor hiding power and dispersibility. This pigment is used mainly for the manufacture of decorative coatings.

The aim of the invention is to improve the hiding power and dispersible ™ red. The iron-containing pigment and the expansion of its scope.

This is ensured by the fact that the red mud is mixed with the pyrite cinder in a ratio of 1: 1-3, depending on the pH, with the addition of phosphoric acid in the amount of 0.8-1.2 wt.% P20s to Fe to add to the subsequent sintering of the pigment. 0z in the pigment and calcine the mixture at 700-800 ° C, then the product is subjected to wet grinding, classification, washing from water-soluble substances, filtration and drying.

The chemical composition of red mud and pyrite cinder are given in table. 1.

When calcining red mud and cinder at 700-800 ° C and washing the product from water-soluble substances, the losses are respectively 12.0 and 10.0%.

PRI me R 1. Take 100 g of red mud from a pH of 9.6 and 100 g of pyrite cinder with a pH of 3.1. Then, 0.90 g of phosphoric acid was added to them, the mixture was thoroughly mixed and calcined at 700 ° C for 2 hours. The resulting product was crushed, classified, washed with water-soluble substances, 4.0 L of water, filtered and dried.

The synthesis yields 178.5 g of pigment and 4.0 l of water containing 22.4 g of potassium and sodium sulfates. The consumption of raw materials amounted to 1.12, including 0.005 phosphoric acid. Pigment in all respects corresponds to TU, dispersibility - 28 microns. (example 3 in table. 2).

Example 2. Take 65 g of red mud sludge pH 9.6 and 135 g of pyrite cinder with a pH of 3.1. Then 0.9 g of phosphoric acid was added thereto, the mixture was thoroughly mixed and

calcined at a temperature of 700 ° C for 2 hours. The resulting product is crushed, classified, washed with water-soluble substances 4.0 l of water, filtered and dried.

As a result of synthesis, 180.2 g of pigment and 4.0 l of water are obtained containing 20.7 g of potassium and sodium sulfates. The consumption of raw materials amounted to 1.11, including 0.005 phosphoric

.acids. In all respects, the pigment corresponds to TU; dispersibility is 29 microns (Example 4, Table 2).

In the table. Figure 2 shows examples of the ps invention and, for comparison, prototype data. It can be seen from the above data that when the cinder mixture increases by more than a 2: 1 ratio, pigment dispersibility worsens. The increase in the mixture of red mud more than 1: 1 leads to an increase in the yield of waste. An increase in the mixture of phosphoric acid or phosphates of more than 1.2% does not affect the dispersibility of the pigments, and a decrease below 0.8% or the absence of lrysodite leads to a decrease in the dispersibility of the pigment.

The pigment can be used not only for paints and varnishes for various purposes, but also in the manufacture of plastics,

rubber.

Claims (1)

SUMMARY OF THE INVENTION A method for producing a red iron-containing pigment from red mud - waste from alumina production, including calcining the mud and then crushing the resulting product, characterized in that, in order to improve the hiding power and dispersibility of the pigment, as well as expand its field of application, the red mud is pre-mixed with pyrite cinder in a ratio of 1: 1-3 in the presence of an addition of phosphoric acid, taken in an amount of 0.8-1.2 wt.% PzOs to ReaO3 in the pigment, and calcination is carried out at 700-800 ° And the pulverized product is classified, washed free of water-soluble substances, is filtered and dried. fifty Table 1 table 2