Study of porous phospho-gypsum composites and their properties on the basis of nostochiometric interpolymer complexes

 
SCIENCE AND INNOVATION 
INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 2 ISSUE 3 MARCH 2023 
UIF-2022: 8.2 | ISSN: 2181-3337 | SCIENTISTS.UZ 
47
bodies (rivers, seas) and laying on land. The first method is practiced only by some states: 
Morocco, Tunisia, the countries of South Africa and Mexico, which is approximately 5% [10]. 
Ground-based storage of waste requires special engineering structures for storage and is carried 
out in the so-called “dry” dumps or in hydraulic dumps (reclaimed or bulk gypsum storage tanks) 
[11,12]. The drive has one or another name depending on the method of transportation: 
- "Dry" (semi-dry selection) - with the movement of wet waste without neutralization by 
road. In Russia, this method is practiced, for example, by Phosphorit Production Association 
(Kingisepp, Leningrad Region) and Apatit BF JSC (Balakovo, Saratov Region). 
- “Wet” (hydrotransport) - the waste is fed to the dump by hydrotransport via a slurry 
pipeline after neutralizing acids in the liquid phase with lime and repulping. Examples are 
enterprises: OJSC Metakhim (Volkhov, Leningrad Region), Production Association Ammofos 
(Cherepovets) and EuroChem-BMU LLC (Belorechensk, Krasnodar Territory). 
In the formation of this kind of mining structures are guided, first of all, by economic and 
environmental principles, the meaning of which is to ensure maximum technical and economic 
efficiency with minimal disturbance of the natural environment. One way or another, the 
ecological balance is disturbed, which is associated with a change in the natural landscape, 
pollution of the soil cover, deterioration of the atmospheric air, changes in the condition and 
properties of rocks that form the foundations of dumps, hydrological and hydrogeological regimes, 
etc. [13,14]. 
The problem of using phosphogypsum as a secondary raw material for the production of 
liquid products has been relevant since the 60s. XX century. The results of numerous studies and 
practices convincingly proved the technical feasibility and feasibility of using phosphogypsum in 
the national economy instead of traditional types of natural raw materials [15]. This is due to the 
content in gypsum from 80 to 98% gypsum, which allows it to be attributed to gypsum raw 
materials. Here it should be noted the most promising areas of using phosphogypsum as a valuable 
large-tonnage secondary resource: 

in agriculture for chemical reclamation of acid and solonetzic soils and composting with 
organic fertilizers; 

in the cement industry, as a mineralizer - additives to the raw material mixture and as a 
regulator of setting speed - instead of natural gypsum; 

for the production of gypsum binders and products, filler in the manufacture of plastics, glass; 

in the construction of roads, the construction of buildings and structures; 

at arrangement of sea and coastal zones; 

for the production of sulfuric acid, etc. 
These examples on the involvement of phosphogypsum are mostly positive, but 
quantitatively this is only 15% worldwide. The remaining 85% are sent to dumps. This is due to 
the fact that phosphogypsum is contaminated with various impurities (sulfuric acid, potassium and 
sodium salts, fluorides and silicofluorides, silicon oxide, rare earth elements, radioactive 
substances, etc.), which do not allow replacing them with natural gypsum. In turn, the need for the 
use of complex and expensive equipment for the preparation of phosphogypsum as a recyclable 
material, as well as existing methods, processes and technologies, require large amounts of energy 
and heat in comparison with the processing of natural gypsum raw materials. Hence the high cost 
of phosphogypsum. An exception are countries that do not have deposits of natural gypsum, for 
example, Japan, which completely processes it. Another factor limiting the use of phosphogypsum 

---