In the study, sodium tripolyphosphate (STPP) was obtained according to the one-stage method. Batch mixes with varied degrees of soda ash neutralization were produced using thermal or wet processing phosphoric acid and/ or recycled STPP calcined in a laboratory rotary kiln. Chromatographic analysis of the phosphate forms showed that products containing as much as 94.73% of a single component were produced. At STPP recycling rates of 2.5 and 5, products with a low bulk density ranging between 0.437-0.547 kg/dm3 were obtained. The recycling of STPP reduces the insoluble substance content, which affects the properties of the product. The phase composition of the products largely depends on the type of recycled phase of sodium tripolyphosphate (phase I and/or phase II) and the calcining temperature.
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