SU755867A1 - Method of annealless strengthening of pelletized materials - Google Patents

Description

The invention relates to the preparation of metallurgical charges for smelting in the units used in the ferrous metallurgy and can be used, for example, for the agglomeration of the charge in the smelting of ferroalloys.

The known method of calcining agglomeration of metallurgical charges using relatively cheap hydraulically hardening cement bond-. [1).

The disadvantage of this method is the long duration of hardening (2-4 weeks, depending on the type of binder) due to the formation of a calcium aluminate hydrosulfate film around cement particles, which hinders further hardening. As a result, 24-30% of cement is not hydrated at all, and therefore does not fulfill its strengthening role. Significantly limits, in some cases, the technological application of the method of high consumption of cement (up to 15%). 25

The closest to the invention to the technical essence is a method for the production of unburned iron ore agglomerated materials, agglomeration with a cement type binder and 30

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water, which includes the thermal-moisture treatment of agglomerated iron ore material, carried out in an electromagnetic field of a current of industrial frequency with a strength of 30-3000 oersted [2] ·.

The disadvantages of this method are the significant duration of the hardening process (4.5 hours) and high consumption of cement.

The purpose of the invention is to reduce the time of hardening agglomerated material.

This goal is achieved by the fact that electromagnetic water is subjected to mixing water or a heterogeneous water-cement solution, followed by hydration of the solution by holding for 1-2 hours and feeding in the amount of 1-5 wt.% Of the agglomerate material for sintering. To reduce the duration of hydration of cement, it is carried out by heating to 100-110 ° C with continuous stirring and grinding of the cement solution.

As a result of the agglomeration of this method, without additional strengthening hardening extract, pellets or

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briquettes with a strength of at least 100 kg / cm, suitable for transportation and use in metallurgical units. Strengthening the mixture of the mixture-solution (water-cement) is achieved by creating a structure of the smallest particles of calcium hydrosilicates with a crystal lattice, akin to the lattice of the tobermorite mineral.

According to known methods, neoplasms of calcium hydrosulfoaluminate (ettrigite) type appear around cement particles in water. Their number is insignificant and is not able to create a solid structure. Appearing on the surface of the particles, the neoplasms form a dense film that impedes the diffusion of water to unreacted cement particles. As a result, hardening occurs very slowly, the reaction ends only after 3-7 days.

In the course of further hardening, the formation of smallest particles of calcium hydrosilicates and compaction of the structure occurs. This process continues for 2-4 weeks. To speed up the hardening process, it is necessary to increase the reactivity of cement to water. As a result of magnetic treatment of water, its physicochemical properties change: coagulation and adhesion of particles suspended in water are accelerated, as a result of which they precipitate, the wetting of the surface of cement particles is improved, their dissolution is accelerated. 'Subsequent exposure of the activated solution for 1-2 hours allows the implementation. Partial prehydration of cement particles. The process is accelerated by continuously mixing the solution and grinding the cement. During the subsequent mixing of the activated and partially hydrated solution with the agglomerated charge materials and briquetting or pelleting in granulators, the final strong structure of hydrosilicates is formed, resulting in hardening of the cement binder and hardening of briquettes or pellets fast within 1-5 minutes. Thus, the process of agglomeration and hardening is combined and additional processing or aging for hardening does not require the obtained pellets or briquettes. The duration of cement hydration is reduced by preheating it to 100110 ° with continuous stirring of the cement activated solution and grinding the cement in the solution.

Example 1 .. Ferrosilicon fractions <3 mm are preformed with cement mortar. The consumption of cement grade 400 is 5% by weight of the concentrated charge. Briquettes tablets ¢) 20 mm and 30 mm high under

pressure of 150 atm. The resulting briquettes after exposure to air for 5, 30 minutes; 1.3 days crush on a press like Amsler.

Example 2. In contrast to example 1, the cement solution is mixed in a magnetic field of strength 200, 1400 and 2000 oersted before mixing with ferrosilicon. After that, the solution is subjected to partial hydration, keeping it for 2 hours and in the amount of 5 wt.% Of the agglomerate mixture is mixed with ferrosicilium. Further operations are carried out according to example 1

Example Z. In contrast to Example 2, the solution to be hydrated is poured into a rotating drum filled with metal balls (40 rpm), the drum with the solution is heated to 110 ° C. Hydration lasts 20 minutes. Further operations are carried out according to example 1.

Test results of compression briquettes

Examples Tension . magnetic fields, oersted Compressive force, kg / briquette Duration of briquette exposure 5 minutes 30 min 1 day 3 days . one - 0.7 0.7 1.5 20 2 200 50 100 120 130 1400 80 120 130 130 2000 85 130 130 130 3 1400 120 130 130 130

The advantages of the method lie in the fact that the duration of hardening of agglomerated briquetting or pelleting materials from hours to 1-5 minutes is reduced, and an operation such as heat and humidifying processing requiring special equipment is eliminated. In addition, the consumption of the binder is reduced to 1-5 wt.% Of the agglomerated charge materials.

As a result, the capacity of the installation increases by 3-4 times without degrading product quality. The use of the proposed method expands the possibilities of briquetting, since the process can be carried out with relatively small pressing efforts of 100–200 kg on presses in mass quantities produced by the domestic industry. Known methods are implemented only with a pressing force of 800 kg or more. The press of this design industry are available only in single copies. The present invention may

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to find wide application in ferroalloy enterprises for briquetting charges intended for smelting ferroalloys, in metallurgical and machine-building enterprises for briquetting or pelleting small fractions of ferroalloys that are not currently in use. Expected savings over 10 million rubles. per year only from involvement in the production of currently unused fines and dusts of ferroalloys.

The introduction of the invention does not require the manufacture of special instruments or equipment, but involves the use of instruments and equipment serially produced by the domestic industry.

Claims (2)

Claim 1. The method of annealing hardening of agglomerated materials. mainly for smelting ferroalloys, including agglomeration with cement type binder and water and treatment in magnet field strength 2002000 oersted, characterized in that, in order to reduce the hardening time of agglomerated material, water is subjected to magnetic treatment 5 mixing or a heterogeneous water-cement solution followed by hydration by holding for 1-2 h, and the amount of the hydrated solution is 1-5 wt.% Of the agglomerate material. 2. The way pop. 1, wherein I D with the fact that, in order to reduce the length of the cement hydration, the hydration is performed pu., The solution was heated up ^to 100-110 C with continuous stirring and cement grinding.