RU2225856C1 - Method for dyeing mineral fertilizers - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: the present innovation deals with obtaining granules of mineral fertilizers of different types with distinctive coloring. It deals with mixing the fuse of mineral fertilizer at weight portion of moisture being 0.2- 0.7%, in particular, the fuse of nitroammophoska, with pigments that should be dosed in dry form and granulating the mixture, moreover, as pigments one should apply red, yellow, brown and black iron oxide pigments, iron oxides (II and III) being their foundation, moreover, pigments should be added into the fuse of mineral fertilizer at the following quantities: red pigment 0.08-1.8%, yellow pigment 0.3-0.7%, brown pigment 1.0-1.5%, black pigment 1-1.5% against ready-to-use product. The present method enables to improve appearance of granulated fertilizers, obtain complicated mineral fertilizers being homogeneous by color, obtain proper color to differentiate fertilizers of one and the same type by brands, and/or against different types of fertilizers, and/or fertilizers of other manufacturers at simultaneous simplifying the process without decreasing physico- mechanical properties of the product. EFFECT: higher efficiency. 4 cl, 1 ex, 1 tbl

Description

The invention relates to the technology of mineral fertilizers with a distinctive color for them and may find application in the production of granular mineral fertilizers of various types.

The use of pigments is well known in the field of mineral fertilizers. A known method of producing mineral fertilizers of potassium chloride with a distinctive or characteristic color. According to this method, for staining the halurgic white potassium chloride in a reddish-brown color, a suspension is used comprising a red iron oxide pigment and a solvent, polyoxyglycol with mol.m. 120-140 units with the addition of water to ensure uniform distribution and disaggregation of the pigment. Processing of the product is carried out in a mixer, the pigment consumption is 100-3000 g per 1 ton of potassium chloride. As polyoxyglycols, diethylene glycol, triethylene glycol, or a mixture thereof, or a mixture of glycols with glycol ethers, or propylene glycol, or glycerols in an amount of 300-5000 g are used [patent 2145950, RU, 1998.04.29].

The disadvantage of this method is the use of water to prepare a pigment suspension in order to ensure uniform distribution of the pigment during surface staining of potassium chloride, which leads to the need for additional drying of potassium chloride after staining and the cost of technology for its production.

A known method for uniform surface staining of mixtures of fertilizers and their products, which includes coating particles of fertilizer with pigments in an amount of 0.1-1% by weight, the coating composition includes white silicate pigments with a particle size of 0.01-1 μm and a surface area of 100-550 m ² / g, at least one pigment with a particle size of 0.1-100 μm and a surface area of 10-100 m ² / g and 0-0.5% oil by weight. The ratio between white silica and other pigments ranges from 1: 3-3: 1. Fertilizing the fertilizers is carried out in two stages, the first stage includes coating the particles with oil and silicon dioxide, the second involves coating the particles with oil and coloring pigment with a particle size of 0.1-100 microns [PCT / N096 / 00269, 1995.11.20].

The disadvantage of this method is that the process of staining fertilizers is complex and multi-stage, requires the use of silicon dioxide with a high specific surface area, iron oxide pigments, vegetable oils and synthetic polymers, which leads to an increase in costs. In addition, fertilizers with a surface coloring of particles quickly become heterogeneous in color during conventional transshipment of fertilizers.

The closest to the proposed technical essence and the achieved result is a method for producing a colored mineral fertilizer, including the use of a pigment suspension in an aqueous solution to obtain mineral fertilizers with a distinctive color, especially complex nitrogen-phosphorus fertilizers. As a pigment suspension, a suspension of finely dispersed carbon in an aqueous solution is used, which is introduced into one stripped off fertilizer pulp with a moisture mass fraction of 10% before being fed to granulation. The amount of pigment is 0.2-1.0 kg of carbon per 1 ton of the finished product [patent 2193018, RU, 2001.05.07].

The disadvantages of this method are that additional equipment is required to prepare a suspension of finely dispersed carbon in water; when finely dispersed carbon is used as a pigment, the color of granular fertilizers is limited to shades of gray; when staining mineral fertilizers obtained by granulating highly concentrated melts with a moisture mass fraction of 0.3-0.7%, the use of an aqueous suspension of pigments leads to excessive wetting of the finished product, deterioration of its physical and mechanical properties, such as strength, caking, dust.

The introduction of iron-containing pigments into the pulp of phosphorus-containing fertilizers with a moisture content of 10% does not allow to color the fertilizers due to discoloration of the pigments when interacting with phosphoric acid salts during granulation and drying of fertilizers [patent 2193018, RU, 2001.05.07].

The objective of the invention is to develop a method for producing granules of mineral fertilizers with a distinctive color.

This goal is achieved by the fact that according to the proposed method for producing colored mineral fertilizers, fertilizer staining is carried out by introducing iron oxide pigment additives into a highly concentrated fertilizer melt with a moisture mass fraction of 0.2-0.7% before the melt is fed to granulation. To ensure disaggregation and uniform distribution of the pigment, it is dosed into the melt in a dry form, uniform coloring of the melt and obtaining a granular fertilizer uniform in color is ensured by intensive mixing of the melt with the addition of pigment, which makes it possible to obtain granules of the finished product having uniform uniform color throughout the volume.

As additives, synthetic red, yellow, brown and black iron oxide pigments are used, the basis of which are iron oxides (II and III). In this case, the pigments are dosed into the melt before feeding it to granulation, in particular into the melt of complex nitrogen-phosphorus-potassium (NPK) -fertilizer, in the following amounts: red 0.08-0.18%, yellow 0.3-0.7 %, brown 1.0-1.5%, black 1.0-1.5% in terms of the finished product.

Achievable technical result - obtaining colored mineral fertilizers of various types, uniform in color; improving the appearance of granular fertilizers; giving fertilizers the desired color with the ability to distinguish fertilizers of the same type by brand, and / or from different types of fertilizers, and / or from fertilizers of other manufacturers.

The red pigment allows you to color granular fertilizers in pink with shades from red-brown to lilac, the color shades in the color of the fertilizer depend on the method of preparation and manufacturer of the pigment. The yellow pigment colors the fertilizer yellow, the brown pigment brown, the black pigment dark gray with a lilac hue.

Tests of the proposed method were carried out using technological media of the current production of nitroammophos (NPK), in particular, nitroammophos melt, with a ratio of N: P ₂ O ₅ - (1.0-1.1): 1.0 or (2.0-2, 1): 1.0 and potassium salts, in particular potassium chloride.

Example. In the mixer, the nitroammophos melt is mixed with a ratio of N: P ₂ O ₅ - (1.0-1.1): 1.0, industrial potassium chloride and red iron oxide pigment in a mass ratio of 73.27: 26.65: 0.08. The melt is granulated, the granules are cooled to a temperature of 20-40 ° C and get the finished product - nitroammofosku (azofosku), painted in pink. The control of color, uniformity of color and appearance of the granules of the finished product is carried out visually. The dosage of pigments is controlled by the mass fraction of iron in the fertilizer.

Similarly, experiments are carried out in which the ratio of the reactants, the additive, the amount of the additive are changed. For comparison, a control experiment is carried out: no pigment is added to the NPK melt, a fertilizer is obtained, which is used as a sample for comparing the color of the granules.

Description of all examples, conditions and results of the experiments are given in the table (experiments 2-14).

Claims (5)

1. The method of coloring mineral fertilizers using pigments, characterized in that as the pigments coloring the fertilizers in a given color, synthetic red, yellow, brown and black pigments are used, the basis of which are iron oxides (II and III), the pigments are dosed in dry form in the melt with a mass fraction of moisture of 0.2-0.7% immediately before the melt is fed to the granulation to ensure disaggregation and uniform distribution of the pigment in the melt, the mixture is intensively mixed. 2. The method according to claim 1, characterized in that for staining the mineral fertilizer in pink with shades from red-brown to lilac, the consumption of red iron oxide pigment is 0.08-0.18% in terms of the finished product. 3. The method according to claim 1, characterized in that for staining the mineral fertilizer in yellow, the consumption of yellow iron oxide pigment is 0.3-0.7% in terms of the finished product. 4. The method according to claim 1, characterized in that for staining the mineral fertilizer brown, the consumption of brown iron oxide pigment is 1.0-1.5% in terms of the finished product. 5. The method according to claim 1, characterized in that for staining the mineral fertilizer in a dark gray color with a lilac hue, the consumption of black iron oxide pigment is 1.0-1.5% in terms of the finished product.