| 摘要 |
The invention concerns a method for determination of the charge state of filtrate from fibre pulp used in the making of paper and cardboard. In the method, a sample from the fibre is filtered through a filter and an indicator colour is added to the filtrate. The absorbency of the filtrate is measured and the charge state of the solution corresponding to the measured absorbency is read off from the corresponding place on a previously constructed calibration curve. In the first embodiment of the invention, the calibration curve is made by taking a sufficient quantity of samples from the same anionic sample and different quantities of cationic substance are added to these samples so that at least some of the samples become cationic and others anionic. The charge state for the filtered samples is determined in known manner, for example, by cationic titration or potentiometric measurement, after which one measures the absorbencies of the samples corresponding to the charge state of the sample, and draws a calibration curve or constructs a table where a given absorbency corresponds to a given charge state. <IMAGE> |
