Influence of Gypsum and Phosphogypsum Dehydration Conditions on the Structure and Technical Properties of the Binder

Technological processes for the production of gypsum and anhydrite binders (dry process) can be divided into three main groups, which differ in the speed of raw material dehydration processes and, as a result, the duration of heat treatment: roasting raw materials in the form of crushed stone in drying drums or rotating furnaces, roasting in gypsum-cooking boilers (infinite heating) and roasting gypsum raw materials in a suspended state (mills, fluidized bed apparatus, etc.). Roasting of gypsum raw materials in a suspended state is characterized by a high rate of dehydration processes. High-speed roasting (techno-impact) leads to the formation of a heterogeneous product consisting of metastable calcium sulfates. Direct heat and mass exchange with the heat carrier makes it possible to significantly accelerate the roasting process and reduce the specific fuel and energy consumption. Increasing the temperature in the reaction zone, increasing the speed of dehydration processes affect the technical properties of the gypsum binder. The influence of raw material dehydration conditions and artificial accelerated aging processes on the technical properties of the binder was studied. Another goal of the experiment was to determine the kinetics of gypsum and phosphogypsum dehydration in order to optimize the processes of dehydration and reduce the water demand of molding mixtures. The practical results of the study should be considered justification of the need for artificial aging and a quantitative assessment of its impact on the quality of the binder. It is recommended to continue the study in order to optimize the processes of dehydration.

Yu.G. MESHCHERYAKOV¹, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
S.V. FEDOROV¹, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
V.P. SUCHKOV², Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Rosatom Technical Academy, Saint-Petersburg branch (4, building A, Aerodromnaya Street, Saint-Petersburg, 197348, Russian Federation)
² Nizhny Novgorod State University of Architecture and Civil Engineering (65, Ilyinskaya Street, Nizhny Novgorod, 603950, Russian Federation)

1. Meshcheryakov Yu.G., Fedorov S.V. Promishlennaya pererabotka fosfogipsa [Industrial processing of phosphogypsum]. St. Petersburg: Stroyizdat. 2007. 102 p.
2. Meshcheryakov Yu.G., Fedorov S.V. Complex industrial processing of the Khibiny apatite concentrate. Increasing the efficiency of production and use of gypsum materials and products: Materials of the IX International Scientific and Practical Conference. Minsk. 2018, pp. 124–127. (In Russian).
3. Udalova E.A., Gabitov A.I., Shuvaeva A.R., Nedoseko I.V., Chernova A.R., Yamilova V.V. Current state and promising possibilities of using phosphogypsum for the production of binders. Istoriya i pedagogika estestvoznaniya. 2016. No. 4, pp. 55–58. (In Russian).
4. Saadaoui E., Ghazel N., Romdhane C.B., Massoudi N. Phosphogypsum: potential uses and problems – a review. International Journal of Environmental Studies. No. 74, pp. 558–567. DOI: https://doi.org/ 10.1080/00207233.2017.1330582
5. Fomenko A.I. Tekhnologii pererabotki tekhnogennogo syr’ya: monografiya. [Technologies for processing technogenic raw materials: monograph]. Moscow: Infra-Engineering. 2018. 136 p.
6. Assakunova B.T., Baymenova G.R., Amankulov M.A. Composite non-fired gypsum binders from local raw materials. Nauka, novye tekhnologii i innovatsii Kyrgyzstana. 2017. No. 10, pp. 26–28. (In Russian).
7. Derevianko V.N., Telyanov V.A. Technologies for the production of gypsum binders from phosphogypsum. Vіsnik PDABA. 2010. No. 2–3, pp. 143–144. (In Russian).
8. Suchkov V.P., Veselov A.V. Mechanochemical activation of natural and technogenic raw materials in the production of high-strength gypsum. Increasing the efficiency of production and use of gypsum materials and products: Materials of the IX International Scientific and Practical Conference. Minsk. 2018, pp. 164–173. (In Russian).
9. Murat M. Structure, cristallochimie, et reactivite des sulfates de calcium. Colloq. Int. de la RILEM: Sulfates de calcium et materiaux derives. Lyon. 1977.
10. Gorbovskiy K.G., Norov A.M., Kulpina Yu.N. Investigation of the kinetics of thermal dehydration of phosphogypsum. Trudy Kol’skogo nauchnogo tsentra RAN. 2019. No. 1 (3). DOI: 10.25702/KSC.2307-5252.2019.10.1.79-86 (In Russian).
11. Lehmann H. Mathiak H, Kurpiers P. Untersuchungen uber Alterungsvorgange an frisch gebranntem Gips. Berichte der Deutschen Keramischen Gesellschaft. 1973. No. 6.
12. Vetegrove H. Homogenizer CLAUDIUS PETERS – gypsum technology to reduce costs and improve quality. Stroitel’nye Materialy [Construction Materials]. 2010. No. 7, pp. 7–12. (In Russian).
13. Vetegrove H. Improving the quality of gypsum binder based on the SMARTGYP PROCESS technology of the CLAUDIUS PETERS company. Stroitel’nye Materialy [Construction Materials]. 2012. No. 7, pp. 37–41. (In Russian).
14. Tischer H.B. Changing the properties of stucco in open storage conditions. Increasing production efficiency and the use of gypsum materials: Materials of the All-Russian seminar. Moscow. 2002, pp. 12–14. (In Russian).
15. Wirsching F X. Gips. Gebruder Knauf Westdeutsche Gipswerke. 1988, pp. 289–315.