SU801566A1 - Method of obtaining pellets - Google Patents

Description

The invention relates to the field of preparation of metallurgical charges for smelting and can be used in the agglomeration of materials from ferrous and non-ferrous metallurgy.

A known method for producing iron ore ores from overwetted concentrates, comprising the addition of a water-decomposing substance, such as calcium hydride.

The disadvantage of this method is its use as a dangerous and deficient and expensive material.

The closest to the invention according to the technical essence is the method of work on the overmoistened activated charges with cement bonding without using water-decomposing substances.

According to this method, the components of the mixture (waterlogged concentrate and Portland cement) are metered in a given ratio, mixed, subjected to mechanical activation and pelletized in a drum granulator. In this case, the work is carried out without supplying water to the pouring layer of embryos. Thus, for example, during the work of magnetite-rich Kokkanarsky concentrate, the charge was overmoistened with a moisture content of concentrate of 10.5% or more. The subsequent hardening of the pellets is carried out at normal and elevated temperatures. The disadvantage of the method is the low strength of the initial and ready-made pellets due to the disruption of the nucleation process and the growth of the gravel of the invention is an increase in the strength of the pellets.

The goal is achieved by the fact that the pelletization of the charge, which is overwetted by 0.1-2.7%, is carried out with an additional periodic water supply to the pouring layer of germs in an amount of 0.01-0.15% of the weight of the charge per pulse at a pulse frequency of 0.5 1.5 min

The initial elements of the charge are the ore waterlogged part (humidity exceeds the optimum value for pelletizing), cement, flux of the additive, etc. dosed in a predetermined ratio, stirred, subjected to mechanical activation by known methods, for example, in a rod mill or disintegrator, activated by blend, Re, 0h

not

61.92 56.71 4.06 5.56

A concentrate with a moisture content of 10.2–13.3%, exceeding the optimum for pelletizing (10.0% or less), the cement (only 4 kg of the mixture) was mixed manually and activated in a 55-liter laboratory rod mill for 5 minutes. The activated waterlogged (moisture 8.7-11.3%) mixture was sieved on a sieve with a cell size of 1 mm to destroy large lumps, and then they were pelletized periodically in a drum granulator with a diameter of 450 mm, feeding water (1 time in 0.5-1 , 5 minutes in an amount of 0.01-0.15% by weight of the charge). The pelletizing time was 30 minutes. It is further strengthened by methods of normal and accelerated hardening. During normal hardening, the cells were strengthened at a temperature of 15-28 ° C for 28 days and the air was pelleted, additionally periodically feeding water to the pouring layer of oats. Raw pellets are further strengthened by known methods - at ordinary temperature, heat and humidity. normal pressure treatment, autoclaving, etc.

The method was tested under laboratory conditions. 3 as the components of the charge, the magnetic concentrate (92% of class minus 74 µm) and the porland cement clinker (cement) of the following composition, crushed to a specific surface of 4000 cm / g, were taken at a ratio of 9: 1 and burned to a specific surface of 4000 cm / g:

wet environment (). Accelerated hardening included a 7-hour heat-moisture treatment at a temperature of 80-100 (07) and subsequent drying of the pellets at a temperature of 200 s for 1 hour (). Examples of the method are given below.

Example 1. In accordance with the prototype, the pelletization of the minimum waterlogized charge (humidity 8.7%) was carried out without supplying water to the pelletizing. In parallel, in accordance with the invention, this mixture was forged, periodically (1 time in 0.5-1.5 minutes in an amount of 0.15% of the weight of the charge), selling water to the pouring layer by germ. The following strength data was obtained

famous8,76,7 1,4

Proposed8,78,5 3,2

76

58 105

40 64. 97 58 As can be seen, the strength of the pellets, when prepared according to the present method, increased by more than 1.5 times with a hard hardening and by 30% with a normal one. The strength of the pellets for compression (P) has more than doubled (from 1.4 to 3.2 kgf / / okat).

With the maximum moisture content of the mixture, the proposed method proved to be especially effective for accelerated hardening, the strength increased almost threefold.

The effect in this case, as can be seen from the presented data, corresponded to that obtained in examples 1 and 2.

It should be noted that the moisture content of raw pellets obtained both in the prototype and in the present method is much lower than the overmoistened charge and varies within a small range (3.1–3.9%). This can be explained by the fact that in the process of the overwetted wet-bed pelletizing, excess moisture is removed from the skin. This moisture forms a film of impurity 3. Experiments were carried out in accordance with Example No. 1, the moisture content of the charge corresponded to the middle of the over-wetting interval. Water was fed periodically in an amount of 0.08% by weight of the mixture 1 time in 0.5-1.5 minutes.

They are removed on the surface of the raw material and are removed during transportation and handling, and if necessary, Q can be removed by special techniques, for example, by blowing the surface of the raw air with air.

Thus, the present method indeed allows to increase the strength of raw and ready-made pellets from the overwetted charge. Thus, the strength of the pellets, which hardened in mode 4, from the overwetted mixture with a moisture content of 11.3% increased 2.9 times. . 6 EXAMPLE 2 Experiments were carried out as in Example 1, using a mixture, the humidity of which (11.3%) was maximum permissible under the conditions of pelletizing. At higher humidity, the pelletizing process was completely disrupted. In this case, water supply was periodically carried out in an amount of 0.01% of the weight of the charge once every 0.5-1.5 minutes.

78015668

those. from 28 to 81 kgf. The increase in procappei according to the claimed method of treating the pellets obtained by means of increasing the consumption of cement

bu prototype, to the level of strength 3.0%.

Claims (1)

METHOD FOR PRODUCING PELLETS ON CEMENT BONDING FROM AN OVERHEATED MIXTURE, including · its pelletizing and subsequent hardening of the pellets at normal and elevated temperatures, characterized in that, in order to increase the strength of the pellets, the pelletizing of the mixture, waterlogged, is lead by 0.1-2.7%, with an additional periodic supply of water to the overflowing layer of embryos in an amount of 0.01-0.15% of the charge weight per pulse at a pulse frequency of 0.5-1.5 min *.