| 摘要 |
<p>PURPOSE: To measure concentrations of five components, i.e., sodium as a main component of salt water or a liquid in a can, chloride ions, and calcium ions, magnesium ions and potassium ions as impurities quickly with high reliability in an in-line fashion in a salt-making process. CONSTITUTION: For an infrared absorption spectrum measured by an FT-IRI, four sets K1 -K4 of a measuring wave number and a reference wave number for measuring the contribution of the HOH deformation vibration of water, one set K5 of a measuring wave number and a reference wave number for measuring the contribution of harmonics of the HOH deformation vibration of water, and one set K6 of a measuring wave number and a reference wave number for measuring the contribution of the symmetric OH stretching vibration of water are selected. An expression of relation between an absorbance difference and an ion concentration is obtained by a multiple regression method using concentrations of calcium, magnesium, potassium, sodium and chloride ions as target variables and absorbance differences of six sets of the measuring wave number and reference wave number as explanatory variables. A salt water or liquid in a can in a slat-making process is introduced to an ART cell 2 by a sampling device 4, and the concentrations of ions are measured by a computer 3 from the absorbance differences and expression of relation.</p> |
