Quality diagnostics of the baked anodes for aluminum electrolytic cells by non-destructive control method

The results of work on the creation of an efficient and economical method, as well as the manufacture and testing of an installation for non-destructive quality control of baked anodes of aluminum electrolytic cells. The installation uses the method of measuring the electrical resistance of the anode and building its calculation model with known data on its geometry and resistivity, as well as the geometry and coordinates of internal defects. In this case, a series of calculations is performed to obtain a 3D matrix of amplitudes and directions of the vectors of the calculated strengths or inductions of the electromagnetic field at points located near the outer surface of the anode. To do this, at least two electrically conductive contacts are placed at these points, passing a given amount of electric current through the anode. Also, at least one sensor is placed near the outer surface of the anode and the amplitude and direction of the magnetic field intensity or induction vectors are measured and displayed in the form of a 3D matrix of the measured intensity or magnetic field induction vectors. After that, the 3D matrices of the calculated and measured vectors of the strength or induction of the magnetic field are compared at the same points located near the outer surface of the anode and, based on these results, the sizes and coordinates of internal defects are determined. The technical result of the implementation of the proposed method is to increase the accuracy, reliability and reliability of determining the location of defects in baked anodes. The installation was tested in laboratory and industrial conditions, which showed good agreement between the results obtained and the data obtained by destructive testing. The entire procedure for checking the quality of one anode took 45-50 s. As a result of preliminary tests, it was determined that out of 100% of the anodes approved for use by the manufacturer, 13.5% were rejected by NDF testing. During research in the Siberian Federal University laboratory, it was found that the accuracy of detecting defective anode blocks using NDF was 82%. Industrial test results of the installation made it possible to divide all anode blocks into 4 classes based on quality, and the validity of this division was confirmed by destructive testing tests.