This article studies the process of recovering the P2O5 contained in ammonium phosphate sediment sludge - formed when extraction phosphoric acid is neutralized with ammonia during the production of monoammonium phosphate - by means of sodium carbonate or sodium hydroxide, and of obtaining the industrially significant product technical sodium tripolyphosphate (Na5P3O10). Phosphate sediment sludge containing 25.47% P2O5, 8.55% CaO, 3.23% MgO, 1.42% Fe2O3 and 1.46% Al2O3 was used as the research object. The influence of the technological parameters affecting the process was determined: at a process temperature of 85-95°C, t = 60-75 min, pH = 6.5-6.7 and an S:L ratio of 1:4÷5, the degree of P2O5 recovery reaches 71.51-72.95%, and it was established that sodium tripolyphosphate meeting standard requirements can be obtained from the recovered solution. The proposed technology makes it possible to reduce P2O5losses compared with the existing method, to reduce the environmental impact of the phosphate sludge, and to develop a practically waste-free, resource-saving production technology.