Scientists at Tomsk State University of Architecture and Construction (TGASU) have patented three methods for synthesizing red phosphors from readily available natural raw materials — limestone, chalk, and marble sand. The developments could be in demand in optoelectronics and the production of building materials, the university reported.

The materials are based on calcium aluminate activated by manganese ions. They convert ultraviolet and blue-violet radiation into red light with peaks around 640–670 nm, as confirmed by X-ray phase analysis and spectrofluorimetry. Such phosphors are used in LED light sources, decorative, and functional building materials.

The key difference from traditional methods is the rejection of expensive chemically pure reagents. Natural raw materials are crushed, mixed with aluminum powder, a manganese compound, and boric acid, and the synthesis is carried out in a conventional muffle furnace with free access to air. Continuous heating eliminates intermediate cooling and re-grinding of the charge, simplifying the process and reducing its energy consumption. TGASU emphasized that the technology relies on raw materials that are abundant in Siberia and other regions of Russia.