One of the quality indicators of the produced mining and chemical raw materials and processed products is their moisture content. Reliable control of humidity requires a lot of labor and time.

The process control system of Nalchik hydromet plant requires operative information on humidity of initial industrial products of KSMP. The currently used thermogravimetric method requires 4 hours for drying of industrial products at a temperature of 105°C to a constant weight ...

When controlling the moisture content of materials with large dielectric losses, schemes that allow measuring the components of the complex resistance of the capacitive transducer are usually used. The greatest sensitivity among them is characterized by bridge meters ...

In resonant methods of moisture measurement, a capacitive sensor with the material under study is in some cases included in the oscillatory circuit of a self-excited oscillator. A change in the moisture content W of the material being monitored leads to a readjustment of the resonant circuit in the anode-grid circuit of the oscillator, which causes a certain increment in the generated frequency. The frequency increment of the self-excited oscillator is converted by frequency discriminators into a direct voltage, which is fed to a measuring instrument. A disadvantage of the considered method of moisture control is the dependence of the operating frequency of the self-excited oscillator on the magnitude of dielectric losses in the material being monitored. At large dielectric losses, the error in moisture measurement can reach significant values. This disadvantage also limits the use of highly sensitive resonant methods.

Selection and maintenance of optimal technological modes of preparation and briquetting, conditions of coal storage and transportation require prompt and objective automatic monitoring of its moisture content.

Moisture content is one of the quality indicators of coal and its products. Measuring the moisture content of low-grade materials is a difficult problem and has not been finally solved.

Numerous methods of measuring the moisture content of solid, liquid and bulk materials are known: conductometric, based on the use of the relationship between moisture and the active resistance of the material; capacitive – between moisture and dielectric permittivity (more precisely – apparent capacitance); neutron; nuclear magnetic resonance – NMR, etc.

Creation of the system for express discrete determinations of phosphate flour moisture content within 0-3,5% was preceded by the study of its electrophysical properties. For this purpose, the dependence lg r = F1 (W) ( r and W - respectively the volume resistivity and moisture content of phosphate flour) was obtained at direct current.