The technological inspection of the electrolyte composition in aluminum production is performed using calibration X-ray quantitative phase analysis (QPA). For this purpose, the use of QPA by the Rietveld method, which does not require the creation of multiphase reference samples and is able to take into account the actual structure of the phases in the samples, could be promising. However, its limitations are in its low automation and in the problem of setting the correct initial values of profile and structural parameters. A possible solution to this problem is the application of the genetic algorithm we proposed earlier for finding suitable initial parameter values individually for each sample. However, the genetic algorithm also needs tuning. A self-configuring genetic algorithm that does not require tuning and provides a fully automatic analysis of the electrolyte composition by the Rietveld method was proposed, and successful testing results were presented.

The present paper provides a combined application of X-ray diffraction (XRD) and X-ray fluorescence (XRF) methods in process control for the analysis of aluminum baths of different compositions. Developed approaches to the combined calibration XRD and XRF methods, independent calibration XRF techniques and to the full-profile automated Rietveld analysis of a bath composition are described.We established that combined XRD-XRF calibration techniques provide an accurate stable analysis of technological parameters in a wide range of traditional and low-melting compositions due to an accurate quantification of CaF 2 , MgF 2 and KF additives. The developed XRF techniques provide quantitative analysis of both cryolite ratio and alumina with the accuracy of 0.03 and 0.25% wt. respectively, which is comparable with the technologically required accuracy.The evolutionary approach that automates full profile quantitative XRD analysis of bath composition and uses XRF data on Ca and Mg provides a better accuracy of measuring cryolite ratio compared to an accuracy of non-automated analysis by Rietveld method.Combined application of the two X-ray methods eliminates gross analytical errors and stabilizes overall performance of a smelter's process control system.