KAOLIN REFLECTANCE SPECTROSCOPY: USING PLS-R TO PREDICT CONTAMINANT CONTENT
ESPECTROSCOPIA DO CAULIM: USO DE PLS-R PARA PREDIZER O CONTEÚDO DE CONTAMINANTES
Paulo Ricardo Nunes da Conceição, Carlos Otávio Petter, Carlos Hoffmann Sampaio, Aaron Young
Abstract
The present study deals with the prediction of contaminant concentrations in kaolin using Partial Least Squares Regression (PLS-R). The aim is to show that PLS-R method can be used to predict contaminant concentration in kaolin. High level kaolin means a kaolin with high-brightness. Since brightness is directly related to the reflectance spectrum and kaolin contaminants affect the reflectance spectrum it is important to the beneficiation of kaolin relates optical features and contaminants. Depending on the product to be produced, the optical parameters will influence how the kaolin will be processed. High-brightness kaolin and two red and yellow inorganic pigments were used to simulate colours contaminants frequently found in Brazilian kaolins, such as, hematite, goethite, rutile and anatase. By adding different pigment concentrations to the pure kaolin, it was possible to create a small dataset containing the visible reflectance spectrum of each sample with the respective optical quality parameters of the kaolin. Results allow us to conclude that PLS-R can predict through the reflectance spectrum the contaminant concentration of the kaolin with R-squared equal 0.9954 for red content and R-squared equal 0.9973 for yellow one.
Keywords
Resumo
O presente estudo trata da predição da concentração de contaminantes presentes no caulim através do uso de Partial Least Squares Regression (PLS-R). O objetivo é mostrar que PLS-R pode ser usada para prever o conteúdo de contaminantes no caulim. Para o caulim ser alto nível é preciso ter alta alvura. Como alvura está diretamente vinculada ao espectro de reflectânica e este é afetado pelos contaminantes é importante para o processamento de caulim relacionar contaminantes com parâmetros ópticos. Os parâmetros ópticos do caulim influenciam como ele será produzido. Caulim de alta alvura e dois pigmentos inorgânicos amarelo e vermelho foram usados para simular contaminantes encontrados no caulim brasileiro, como, hematita, goetita, rutilo e anatásio. Adicionando diferentes concentrações de pigmento ao caulim puro, foi possível criar uma base de dados contendo o espectro de reflectância de cada amostra com seus respectivos parâmetros ópticos de qualidade. Conclui-se que PLS-R, através do espectro de reflectância, pode prever as concentrações dos contaminantes do caulim contaminado com R2 igual a 0,9954 para contaminante vermelho e R2 igual a 0,9973 para amarelo.
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Referências
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