Platov South-Russian State Polytechnic University (NPI) (Novocherkassk, Russia):

Shabelskaya N. P., Professor, Doctor of Engineering Sciences, Associate Professor, nina_shabelskaya@mail.ru
Medvedev R. P., Applicant

In this work, inorganic fluorescent dye fillers are obtained from the waste generated when producing phosphoric acid from apatite. The search for a method for processing waste products of phosphoric acid production into high-demand products is a very urgent task. Currently, the main area of phosphogypsum recycling is the manufacture of such building materials as wall panels, dry mixes, etc. It is also used for land reclamation. However, such use of phosphogypsum, which is the most valuable raw material for the production of a number of important inorganic substances, is impractical from the economic point of view. In this regard, a study aimed at developing methods for producing popular products, in particular inorganic luminescent dyes, from large-tonnage industrial wastes is of particular relevance. The possibility of synthesizing an inorganic fluorescent dye from phosphogypsum using coal, sucrose, and citric acid as reducing agents is first discussed in this work. The samples obtained are studied by scanning electron microscopy (SEM) using electron probe microanalysis (EPMA). It is established that the main component of phosphogypsum (calcium sulfate) may be converted into a luminescent material (calcium sulfide) under the influence of various reducing agents, in particular coal, citric acid, and sucrose. It is discovered that the materials obtained glow with an orange light under ultraviolet radiation. When using citric acid and sucrose as reducing agents, the glow is uniformly distributed over the surface of the sample.

1. Xu J. P., Fan L. R., Xie Y. C., Wu G. Recycling-equilibrium strategy for phosphogypsum pollution control in phosphate fertilizer plants. Journal of Cleaner Production. 2019. Vol. 215. pp. 175–197.
2. El Zrelli R., Rabaoui L., Abda H., Daghbouj N., Perez-Lopez R., Castet S., Aigouy T., Bejaoui N., Courjault-Rade P. Characterization of the role of phosphogypsum foam in the transport of metals and radionuclides in the Southern Mediterranean Sea. Journal of Hazardous Materials. 2019. Vol. 363. pp. 258–267.
3. Sizyakov V. M., Utkov V. А., Brichkin V. N., Gumenyuk A. M. Limestonenepheline mix composition conditioning by using alkali-free feed additives. Obogashchenie Rud. 2017. No. 1. pp. 51–55. DOI: 10.17580/or.2017.01.10.
4. Isakov A. E., Мatveeva V. A. ОАО «Kovdorsky MCC» manganese-containing waste water purification study. Obogashchenie Rud. 2016. No. 2. pp. 44–48. DOI: 10.17580/or.2016.02.08.
5. Nikiforova E. M., Eromasov R. G., Vasilyeva М. N. The Sorsky Mining Complex molybdenum ores flotation tailings recycling in cellular thermalinsulating- structural ceramics production. Obogashchenie Rud. 2017. No. 1. pp. 40–45. DOI: 10.17580/or.2017.01.08.

6. Kachurin N. M., Kalaeva S. Z., Vorobyev S. A. Production of magnetic fluids from industrial wastes. Obogashchenie Rud. 2015. No. 2. pp. 47–52. DOI: 10.17580/or.2015.02.10.
7. Szajerski P., Celinska J., Bern H., Gasiorowski A., Anyszka R., Dziugan P. Radium content and radon exhalation rate from sulfur polymer composites (SPC) based on mineral fillers. Construction and Building Materials. 2019. Vol. 198. pp. 390–398.
8. Miekos E., Zielinski M., Kolodziejczyk K., Jaksender M. Application of industrial and biopolymers waste to stabilise the subsoil of road surfaces. Road Materials and Pavement Design. 2017. Vol. 20, No. 2. pp. 440–453.
9. James J. Strength benefit of sawdust/wood ash amendment in cement stabilization of an expansive soil. Revista Facultad de Ingenieria. 2019. Vol. 28, No. 50. pp. 44–61.
10. Michalovicz L., Muller M. M. L., Tormena C. A., Dick W. A., Vicensi M., Meert L. Soil chemical attributes, nutrient uptake and yield of no-till crops as affected by phosphogypsumdoses and parceling in southern Brazil. Archives of Agronomy and Soil Science. 2019. Vol. 65, No. 3. pp. 385–399.
11. Fedotov P. S., Petropavlovskiy I. А., Norov А. М., Malyavin A. S., Ovchinnikova К. N. Preparation of PKSfertilizers of 0-20-20-5S brand using various phosphate raw materials. Khimicheskaya Promyshlennost’ Segodnya. 2016. No. 2. pp. 6–11.
12. Yang B. J., Yang M. M., Wang B. N., Fang X. Y., Wan Q. A new route to synthesize calcium carbonate microspheres from phosphogypsum. Materials Research Express. 2019. Vol. 6, No. 4. Paper 045042.
13. Altiner M., Top S., Kaymakoglu B., Seckin I. Y., Vapur H. Production of precipitated calcium carbonate particles from gypsum waste using venturi tubes as a carbonation zone. Journal of CO₂ Utilization. 2019. Vol. 29. pp. 117–125.
14. Ennaciri Y., Bettach M. Procedure to convert phosphogypsum waste into valuable products. Materials and Manufacturing Processes. 2018. Vol. 33, No. 16. pp. 1727–1733.
15. Telesca A., Marroccoli M., Winnefeld F. Synthesis and characterisation of calcium sulfoaluminate cements produced by different chemical gypsums. Advances in Cement Research. 2019. Vol. 31, No. 3. pp. 113–123.
16. Kosynkin V. D., Selivanovskiy A. K., Fedulova T. T., Smirnov K. M., Krylova O. K. Comprehensive phosphogypsum treatment with the recovery of chemically precipitated chalk, gypsum, and REE concentrate. Tsvetnye Metally. 2012. No. 3. pp. 31–34.
17. Zhuang Y. F., Li T. Y., Yuan P., Li Y. Q., Yang Y. M., Yang Z. P. The novel red persistent phosphor CaS:Yb²⁺, Cl–potentially applicable in AC LED. Applied Physics A. Materials Science & Processing. 2019. Vol. 125, Iss. 2. Artcle 141.
18. Tong X. B., Yang J. X., Wu P. P., Zhang X. M., Seo Y. J. Color tunable emission from CaS:Cu⁺, Mn²⁺ rare-earthfree phosphors prepared by a simple carbon-thermal reduction method. Journal of Alloys and Compounds. 2018. Vol. 779. pp. 399–403.