RU2464360C1 - Anodic mass obtaining method - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: in anodic mass obtaining method involving preliminary separate heating of coke charge, coke charge and peck, mixing of coke charge in mixer, introduction to the mixer of molten peck and coke dust and their mixing with coke charge, coke dust and molten peck, prior to introduction to the mixer, is provided with heteropolar electric charges; then, heteropolar charged mixture is supplied to mixer for mixing with coke charge. Provision of coke dust and peck with heteropolar charges is performed during 1-3 seconds with voltage on electrodes of high-voltage charging devices within 24000÷50000 V DC.

EFFECT: improving homogeneous mixing of components of anodic mass at its manufacture.

2 cl, 1 dwg

Description

The invention relates to non-ferrous metallurgy, in particular to a method for the production of anode paste for self-baking anodes of aluminum electrolysis cells, and can be used in the production of baked anodes.

The qualitative characteristics of the anode mass, when used in the electrolysis process, are as follows: the minimum foam output into the electrolyte and the lowest anode consumption during aluminum electrolysis. These indicators largely depend on the quality of mixing and impregnation of the components of the mixture with pitch at the stage of preparation of the anode mass. This process is most difficult for the dust fraction. Therefore, to improve the quality of the anode mass, the process of mixing and impregnating the dust fraction of the coke charge with the pitch is most important.

A known method of preparing the mixture to obtain the anode mass of self-baking anodes for aluminum production (SU 1497284 USSR, publication date 07/30/1989, class C25C 3/12), including mixing the dry components of the mixture, processing them with a plasma stream with a temperature of 3000-6000K for 0.1- 0.5 s, and pressing.

The disadvantage of this method is the increased requirements for heat and heat resistance of equipment for the production of anode paste, capable of withstanding the temperature of the plasma. At the same time, there is a risk of complete combustion of small particles of coke, which can lead to an increase in its consumption in the production of the anode mass. In addition, the ash content of the anode mass increases, significantly worsening its properties.

The closest to the claimed invention in technical essence and the achieved result is a method for the production of anode paste (patent RU 2312938, publication date 12/12/2007, class IPC C25C 3/12), including preliminary separate heating of the coke charge, coke dust and pitch, mixing coke charge in the mixer, introducing molten pitch and coke dust into the mixer and mixing it with the coke charge. To increase the ductility of the anode mass and to reduce the pitch content in it, coke dust is separately mixed with molten pitch in a hydro-shock cavitation dispersant, then the resulting mixture is fed to the mixer for mixing with a coke charge. Mixing the molten pitch with coke dust and mixing the resulting dust-free composition with coke charge is carried out at a pressure of not more than 100 mbar.

The disadvantage of this method is the significant, of the order of 10 minutes, the mixing time of coke dust with pitch in a hydraulic shock-cavitation dispersant, which significantly reduces the performance of the installation. Another disadvantage is the low quality of coke dust impregnation with pitch in a hydraulic shock-cavitation dispersant due to only mechanical impact on them and, as a result, the low quality of the produced anode mass, which does not meet modern requirements of electrolysis production.

Thus, the proposed method is time-consuming, time-consuming and ineffective.

The objective of the invention is: to reduce the preparation time of the anode mass; increasing the efficiency of mixing the components of the anode mass - coke charge, coke dust and pitch; an increase in the ductility of the anode mass with a simultaneous increase in the productivity of the apparatus for its production.

The technical result consists in increasing the uniformity of mixing the components of the anode mass during its production.

This object is achieved in that in a method for the production of the anode mass, including preliminary separate heating of the coke charge, coke dust and pitch, mixing the coke charge in the mixer, introducing molten pitch and coke dust into the mixer and mixing them with the coke charge, according to the claimed invention, coconut dust and the molten pitch, before being introduced into the mixer, is charged with bipolar electric charges, then a bipolar-charged mixture is fed into the mixer for mixing with the coke charge.

The method is supplemented by private distinctive features, also aimed at achieving the specified technical result.

The time to give proper charge to the pitch and coke dust depends on the electric field strength (voltage on the electrodes of the charging unit). Thus, the required charge of pitch and coke dust at a voltage of 24,000 V is achieved in 3 s, and at a voltage of 50,000 V - in 1 s. Therefore, the most acceptable is the voltage range on the electrodes of the charging unit 24000-50000 V, at which the time of charging charges to the pitch and dust particles is the optimal value (to ensure the necessary production line productivity) 1-3 s.

In relation to the prototype of the proposed method has the following differences. Immediately before introduction into the mixer, coke dust and molten pitch are charged with bipolar charges in high voltage charging installations, while the pitch is charged with a negative charge by the contact charging method, and coke dust is charged with a positive charge by the combined method of contact and triboelectrification.

The difference of the proposed method is that the coke charge, bipolar charged coke dust and pitch are fed into the mixer for mixing. When mixing, when coke dust and pitch are charged in different polarity, unipolar charged dust particles, repelling from each other without forming lumps, are distributed over almost the entire surface of the pitch, which increases the active surface of coke dust and improves its wetting by pitch. And then the multipolarly charged particles of coke dust and pitch are attracted to each other, which also improves the quality of mixing and wetting of coke dust, and, as a result, the quality of mixing of all components of the anode mass.

The drawing shows a diagram of the installation for implementing the proposed method for the production of anode mass.

The installation consists of a coke dust bin 1, bunkers of coke charge components 2, batchers of charge, dust and pitch components 3, 4, and 8, respectively, coke charge heaters and coke dust 6 and 9, respectively, transport augers 5, high-voltage charging units 7, a mixer 11 and extruder 10.

The method is as follows.

The components of the coke charge by the batchers 3, from the bins 2, transport augers 5 are fed into the batch heater 6, where it is preheated to a temperature of 200-220 ° C. The heated components of the coke charge are fed into the mixer 11.

Coke dust from the hopper 1 dispenser 4 is loaded into a dust heater 9 and is also heated to a temperature of 200-220 ° C. In the pitch batcher 8 serves pitch preheated to a temperature of 200-240 ° C. Then, the pitch and coke dust enter the high-voltage charging units 7, where they acquire electric charges within 1-3 s, the pitch - negative, and coke dust - positive. In this case, the voltage at the electrodes of high-voltage charging installations is within 24000 ÷ 50,000 V DC. Thus charged pitch and coke dust also enter the mixer 11, where they are mixed with each other and with the coke charge for 3-4 minutes. From the mixer, the anode mass is fed into the extruder 10 and after forming the briquettes in it, the anode mass is ready. The process of preparing the anode mass took 4-5 minutes, while the mixing process in the mixer provides a homogeneous mass with the necessary physical and chemical parameters.

The proposed method improves the efficiency of mixing and impregnation with a pitch of the pulverulent fraction of the coke charge.

Claims (2)

1. The method of production of the anode mass, including preliminary separate heating of the coke charge, coke dust and pitch, mixing the coke charge in the mixer, introducing molten pitch and coke dust into the mixer and mixing them with coke charge, characterized in that the coke dust and the molten pitch before introduction into the mixer is charged in a multi-polar manner in high-voltage charging installations, while coke dust is given a positive charge and the pitch is negative, then coke dust mixed in different ways is charged and pitch is fed into the mixture tel and mix with coke charge. 2. The method according to claim 1, characterized in that the imparting of bipolar charges of coke dust and pitch is carried out for 1-3 with a voltage on the electrodes of high-voltage chargers in the range of 24000 ÷ 50,000 V DC.

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