ABOUT THE SUSPENSION EFFECT IN PHOSPHOGYPSE SAMPLES
Rubrics: 1. CHEMISTRY
Authors:
1.
N.G. Chernishevsky Saratov State University
Type:
Article
Pages:
from 16
to 23
Status:
Published
Received:
23.12.2025
Accepted:
25.12.2025
Published:
25.12.2025
Language:
Russian
Keywords:
PHOSPHOGYPSUM, HYDROGEN INDEX, SUSPENSION EFFECT, ELECTRIC CURRENT
Abstract (English):
The suspension effect (SE) in samples of phosphogypsum, a by-product of phosphorus production, was studied. Laboratory experiments revealed a significant difference in pH values between phosphogypsum-based soil pastes and their filtrates. Spatial differentiation of SE has been established: acidic SE was observed in the initial samples and near the anode zone of the geoelectrochemical device, alkaline SE was recorded in the cathode region. A sharp increase in SE in samples has been experimentally proven when a direct electric current of 0.25 A is applied to samples for 36 minutes: in the anode zone, the absolute values increase by 17 times, in the cathode zone - by 8.5 times. This process is accompanied by a 6.5-fold increase in the mineralization of the aqueous extract, indicating intensive electrochemical dissolution of the gypsum matrix, migration of ionic components (Ca2+, SO42-) into the liquid phase, activation of electrolytic dissociation processes and the formation of new mineral phases (anhydrite in the anode, siderothyl in the cathode zones). The conditions of electrical neutrality of the samples (isoelectric point) at 280 mg/dm3 decanate mineralization and pH 5.66 have been determined. The results obtained make it possible to control the electrochemical dissolution of gypsum, ion migration and leaching of toxic elements (fluorine, phosphates, strontium), as well as to control the properties of phosphogypsum-based composites by regulating the electrochemically modified surface of phosphogypsum microcrystals due to the parameters electrical treatment (current density 0.15 A/cm2, exposure time 20-60 min). This opens up prospects for expanding the industrial use of phosphogypsum in the production of building materials and reducing the environmental burden through a closed cycle of processing this man-made material.
The suspension effect (SE) in samples of phosphogypsum, a by-product of phosphorus production, was studied. Laboratory experiments revealed a significant difference in pH values between phosphogypsum-based soil pastes and their filtrates. Spatial differentiation of SE has been established: acidic SE was observed in the initial samples and near the anode zone of the geoelectrochemical device, alkaline SE was recorded in the cathode region. A sharp increase in SE in samples has been experimentally proven when a direct electric current of 0.25 A is applied to samples for 36 minutes: in the anode zone, the absolute values increase by 17 times, in the cathode zone - by 8.5 times. This process is accompanied by a 6.5-fold increase in the mineralization of the aqueous extract, indicating intensive electrochemical dissolution of the gypsum matrix, migration of ionic components (Ca2+, SO42-) into the liquid phase, activation of electrolytic dissociation processes and the formation of new mineral phases (anhydrite in the anode, siderothyl in the cathode zones). The conditions of electrical neutrality of the samples (isoelectric point) at 280 mg/dm3 decanate mineralization and pH 5.66 have been determined. The results obtained make it possible to control the electrochemical dissolution of gypsum, ion migration and leaching of toxic elements (fluorine, phosphates, strontium), as well as to control the properties of phosphogypsum-based composites by regulating the electrochemically modified surface of phosphogypsum microcrystals due to the parameters electrical treatment (current density 0.15 A/cm2, exposure time 20-60 min). This opens up prospects for expanding the industrial use of phosphogypsum in the production of building materials and reducing the environmental burden through a closed cycle of processing this man-made material.
Keywords:
PHOSPHOGYPSUM, HYDROGEN INDEX, SUSPENSION EFFECT, ELECTRIC CURRENT
PHOSPHOGYPSUM, HYDROGEN INDEX, SUSPENSION EFFECT, ELECTRIC CURRENT
