RU2243194C2 - Method of manufacturing alkali metal humates - Google Patents

Abstract

FIELD: mixed fertilizers.

SUBSTANCE: object of invention is preparation of fertilizers from solid combustible fossils and, in particular, consists in mixing ground coal containing at least 50% humin acids with alkali additives in rotary mixer. First, total batch of coal is loaded and then alkali is added at a velocity maintaining temperature of reaction mixture in the range of 70-80^оС, alkali-to-coal weight ratio being (0.125-0.150):1.

EFFECT: reduced expenses on providing humin acids.

2 tbl, 5 ex

Description

The invention relates to the production of fertilizers from solid fossil fuels and can be used to obtain humates of alkali metals.

A known method of producing humic fertilizers (USSR AS No. 220278 IPC C 08 F 11/02, application. March 29, 1966), according to which solid fossil fuels are treated with an alkali solution at 100 ° C, followed by treatment with ammonia.

The disadvantage of this method is the rather low extraction of humic acids.

The closest technical solution is a method for producing alkali metal humates (according to RF patent No. 2036190) by ultrafine grinding of coals containing natural humic acids together with potassium and / or sodium carbonates. The essence of the known method consists in ultrafine dispersion of the specified mixture in the mode of mechanochemical activation, which provides the possibility of solid-phase conversion of humic acids into water-soluble humates of alkali metals. The known method has the following disadvantages:

- the output of a commercial product and the productivity of equipment are reduced due to excess moisture contained in coal and adsorbed by alkaline agents from the air; excess moisture accelerates the reaction, the temperature of the reaction mixture rises rapidly, which leads to the tarring of coal and stopping the process;

- alkali metal carbonates due to low nucleophilicity are used in excess quantities (the mass ratio of coal to alkaline agents is 1: 0.8-1.2, which leads to the need to increase their consumption and, as a result, to an excess norm increase in the pH of aqueous solutions of humates in the consumer to values of 9.8- 10;

- the final product has the form of a fine powder, very dusty, which reduces its consumer properties.

An object of the invention is to develop a method for producing humic fertilizers, which allows to reduce the cost of its production and at the same time to process the humic-containing material with an alkaline agent (additive) to obtain fertilizer in granular form.

The problem is achieved in that in the method for producing humates of alkali metals, comprising mixing crushed coal with a content of humic acids of at least 50% with an alkaline additive, according to the invention, the mixing of crushed coal with an alkaline additive is carried out in a rotary mixer, into which a full batch of crushed coal is first loaded and the alkaline additive is introduced into the rotary mixer at a speed that ensures the temperature of the reaction mixture is within 70-80 ° C, and the mass ratio of alkaline additives and crushed coal is 0.125-0.150: 1.

Analysis of known sources did not reveal the distinguishing features of the invention, therefore, the claimed technical solution meets the criterion of "novelty."

Due to the fact that the alkaline additive is introduced into the mixture in the claimed ratio, and the process temperature is maintained within 70-80 ° C, the particles of the formed humates stick together, roll up and form granules with sizes from 0.5 to 10 mm (with an increase in temperature above the specified limit, the extraction of coal tar and particles stick together into larger aggregates up to 100-150 mm in size). A distinctive feature of the proposed method is that the temperature range of the reaction mixture (70-80 ° C) and the ratio of the mass of coal and alkaline additive are constant, and the time intervals between the supply of the next portion of the alkaline additive and its mass vary insignificantly depending on the design mixing device and desired performance. But the only criterion for choosing the indicated intervals between portions is the temperature of the reaction mixture.

The process is based on a simple base acid neutralization reaction:

R-COOH + NaOH = -COONa + H ₂ O + 56 kJ

The humic acid molecule consists of regularly repeating fragments, the structure of which is established relatively recently (Soil Science No. 2, 2002, pp. 150-157). The molecular weight of one fragment is 6363 cu and each fragment contains 26 groups - COOH and, therefore, when neutralized, forms 26 moles of water with the release of 1456 kJ of heat. The evaporation of 26 moles of water requires only 1176 kJ of thermal energy. Thus, in the rational conduct of the process, the amount of heat released during the reaction is more than enough to evaporate the moisture formed during the reaction. The essence of the proposed technical solution lies in the maximum use of this thermal energy. This is achieved by the fact that one of the components of the process - alkali is introduced gradually, this allows you to reduce heat loss into the environment and maximize the use of thermal energy to warm the reaction mass to the desired temperature, avoiding overheating.

Given that this invention allows to obtain, in comparison with the prototype and other sources of humic acids, humates of alkali metals in the form of granules directly in the process of solid-phase conversion and significantly reduce the consumption of alkaline additives, the proposed solution meets the criterion of "inventive step".

The process according to the invention is as follows:

- the whole mass of coal with a content of humic acids of at least 50% and a natural humidity of 20 to 30% is loaded into the mixer before the start of the process,

- the introduction of alkaline agents - additives (NaOH, KOH, K ₂ CO ₃ ) are carried out portionwise with constant monitoring of the temperature of the reaction mixture so that the mixture is heated as a result of the exothermic reaction does not exceed 80 ° C, and the mass ratio of alkaline agents to coal remains within 0.125-0.150: 1, the process completion time is determined visually when humate dust appears instead of moisture vapor from the neck of the mixer in the inspection window.

The implementation of the method is illustrated by the following examples.

Example 1

In the mixer with a capacity of 7 cubic meters. m, rotating along an inclined axis at a speed of 2 revolutions per minute, loaded 1 ton of coal containing 80.2% of natural humic acids, and they started loading granulated caustic soda in portions of 10-11 kg with an average feed rate of 2.3 kg / min. Caustic soda was supplied in this mode for 70 min, thus loading 161 kg. The ratio of alkaline agent to coal was 0.16: 1. By the time loading is complete, the temperature in the mixer has reached 95 ° C. After that, the material was mixed in a mixer until cooling. The experimental conditions are given in table 1. The characteristics of the product obtained after unloading the mixer are presented in table 2.

Example 2

Analogously to example 1, 2 tons of coal were loaded into the mixer. Caustic soda was fed in portions of 15-20 kg at an average feed rate of 1.5 kg / min for 120 minutes. A total of 180 kg of caustic is loaded with a ratio of 0.09: 1 to coal. The maximum temperature in the mixer was 65 ° C. The data are presented in tables 1 and 2.

Example 3

The experiment was carried out analogously to example 2, but the caustic was loaded for 200 minutes in portions of 25-30 kg at an average speed of 1.5 kg / min.

The total consumption of caustic soda was 300 kg with a ratio of 0.15: 1.

The maximum temperature in the mixer is 80 ° C. The data are presented in tables 1 and 2.

Example 4

Similarly to examples 1-3, coal loading 3 tons, caustic loading - 400 kg, feed rate 1.5 kg / min. The ratio of 0.13: 1. The results in tables 1 and 2.

Example 5

Similarly to examples 1-4, the loading of coal is 4 tons, the loading of caustic soda is 500 kg, the feed rate of caustic soda is 1.9 kg / min, the process time is 260 minutes.

The data in the tables show that in order to achieve almost complete conversion of humic acids into sodium or potassium humates, with an optimal particle size distribution of the final product and a low pH of its 0.01% solution, the process parameters are in the following ranges:

- The average feed rate of an alkaline agent is 1.2-1.9 kg / min,

the mass ratio of alkaline agent and coal is 0.125-0.15: 1,

- the maximum temperature of the reaction mixture is 70-80 ° C.

The advantages of the invention in comparison with the prototype are as follows:

1. Obtaining the final product in the form of granules.

2. The exclusion of energy costs for conditioning the reaction mixture to a moisture content of 7-12%.

3. Reducing the consumption of alkaline agents by 40-50%.

Claims (1)

A method of producing alkali metal humates, comprising mixing crushed coal with a content of humic acids of at least 50% with an alkaline additive, characterized in that the mixing of crushed coal with an alkaline additive is carried out in a rotary mixer, into which a full batch of crushed coal is first loaded, and the alkaline additive is introduced into a rotating mixer at a speed that ensures the temperature of the reaction mixture is within 70-80 ° C, and the mass ratio of alkaline additives and crushed coal is 0.125 - 0.150: 1.