Tamping paste for aluminum electrolytic cell and use method of tamping paste

Abstract

The invention discloses tamping paste for an aluminum electrolytic cell and a use method of the tamping paste. The tamping paste mainly comprises carbonaceous aggregate, a binder, metal powder, an expansion agent and a curing agent. Normal-temperature tamping connection is conducted through the high-expansion high-conductivity tamping paste, and assembly is completed through the working procedures of paste preparation, cleaning of a dovetail groove and a cathode steel bar, laying of the thin-layer tamping paste on the bottom face of the dovetail groove, placing of the cathode steel bar, filling and tamping of the tamping paste, normal-temperature curing and the like. Compared with existing tamping paste and a use method of the existing tamping paste, the tamping paste for the aluminum electrolytic cell and the use method of the tamping paste have the beneficial effects that operation under the normal temperature is easy, and expansion and conductivity are high; the property of conduction between the cathode steel bar and a carbon block and the conductive property of the steel bar paste are improved, the aluminum electrolytic cell cathode voltage drop is reduced, the aluminum electrolysis energy consumption is saved, and the service life of an aluminum electrolytic cathode is prolonged.

Description

technical field [0001] The invention relates to the technical field of aluminum electrolysis, in particular to a tamping paste for an aluminum electrolysis cell and a method for connecting aluminum electrolysis cathode steel rods and carbon blocks. Background technique [0002] Industrial primary aluminum production has always adopted the Hall-Heroult aluminum electrolysis process. Aluminum electrolytic cells are the core key equipment for primary aluminum production. Their service life and quality determine various technical and economic indicators in the aluminum electrolytic production process. The cathode is a key component of the aluminum electrolytic cell, and its material and assembly quality directly affect the cathode voltage drop, which in turn affects the energy consumption index. The cathode voltage drop refers to the voltage drop between the upper surface of the cathode carbon block in the electrolytic cell and the outlet end of the cathode conductive steel rod....

AI Technical Summary

Problems solved by technology

[0003] Existing aluminum electrolysis cathode steel rod assembly mostly adopts phosphorus pig iron casting method or traditional tamping paste tamping method to connect cathode steel rod and carbon block together, they all have certain shortcomings, adopt the shortcoming of phosphorus pig iron casting method as follows: (1 ) before tamping, it is necessary to preheat the carbon block and steel rod to high temperature before pouring, which requires energy consumption and increases the cost. At the same time, due to the large temperature difference between the two ends of the steel rod, it is easy to cause the steel rod to bend and deform, and the surface of the dovetail groove is oxidized and peeled at high temperature , which brings hidden dangers to the interface between phosphorus pig iron and carbon block, especially after high-temperature pouring and two thermal shocks at the start of roasting, it is even more unfavorable to the interface

(2) When using phosphorus pig iron for tamping, because the cathode assembly adopts intermittent pouring, the fluidity of iron is required to be high. The two elements of phosphorus and iron can reduce the viscosity of molten iron, but too much phosphorus increases the viscosity of phosphorus pig iron. The cold brittleness of the ring; the phosphorus pig iron ring is very easy to break after pouring, and even cause the cathode steel rod and carbon block to fall off, which increases the risk of aluminum electrolysis operation and production

(3) When phosphorus pig iron is used repeatedly, its composition will change, the confinement effect will become worse, and tiny gaps will appear, which will increase its resistance and energy consumption.

(4) It is difficult to clean the phosphorus pig iron sticking on the steel rod when taking out the cathode, which makes the work more difficult and the operating cost increases. The long-term existence of phosphorus pig iron on the cathode steel rod will corrode the cathode steel rod and cause damage to the cathode steel rod

The disadvantages of using the traditional tamping paste tamping method are as follows: Although it is more convenient to cast than phosphorus pig iron and the cost is lower, the most important reason for the high contact pressure drop between the current cathode steel rod and carbon block is that the steel rod paste interacts with the carbon block during the high temperature process. The thermal matching between the block and the cathode steel rod is poor, followed by the conductivity of the steel rod paste itself needs to be improved