Quantification of CaCO_3-CaSO_3 centre dot 0.5H_2O-CaSO_4 centre dot 2H_2O mixtures by FTIR analysis and its ANN model

摘要

A new quantitative analysis method for mixtures of calcium carbonate (CaCO_3), calcium sulphite hemihydrate (CaSO_3 centre dot 1/2H_2O) and gypsum (CaSO_4 centre dot 2H_2O) by FTIR spectroscopy is developed. The method involves the FTIR analysis of powder mixtures of several compositions on KBr disc specimens. Intensities of the resulting absorbance peaks for CaCO_3, CaSO_3 centre dot 1/2H_2O and CaSO_4 centre dot 2H_2O at 1453, 980, 1146 cm~(-1) were used as input data for an artificial neural network (ANN) model, the output being the weight percent compositions of the mixtures. The training and testing data were randomly separated from the complete original data set. Testing of the model was done with saccessfully low-average error levels. The utility of the model is in the potential ability to use FTIR spectrum to predict the proportions of the three substances in unknown mixtures.