Open AccessFeatures of the synthesis of highly dispersed alumophosphates AlPO4·nH2O
Author(s) -
Л. С. Ещенко,
A. V. Paniatouski
Publication year - 2021
Publication title -
vescì nacyânalʹnaj akadèmìì navuk belarusì. seryâ hìmìčnyh navuk
Language(s) - English
Resource type - Journals
eISSN - 2524-2342
pISSN - 1561-8331
DOI - 10.29235/1561-8331-2021-57-3-310-319
Subject(s) - monoclinic crystal system , anhydrous , nucleation , particle size , dehydration , particle (ecology) , materials science , condensation , chemistry , mineralogy , chemical engineering , crystallography , crystal structure , organic chemistry , thermodynamics , biochemistry , oceanography , physics , engineering , geology
Aluminum orthophosphate of the composition AlPO 4 ·2H 2 O with a monoclinic structure identical to the structure of the natural mineral metavariscite was obtained by condensation method during hydrothermal treatment of alumophosphate solutions with a concentration (g/l) of Al 2 O 3 90 – 115, P 2 O 5 340 – 440 in the temperature range 95–99 °C. For the first time, the role of aging of the alumophosphate system in shortening of the induction period, simultaneous nucleation of primary particles in the entire volume of the solution and the formation of a pasty product with a predominant particle size of 1–10 μm, in contrast to 30–50 μm, characteristic of a fine-crystalline product obtained without aging of the solution, is established. It is shown that pasty AlPO 4 ·2H 2 O, in comparison with fine-crystalline, is hardly soluble in HCl even under prolonged heating. The influence of P 2 O 5 content in the alumophosphate solution, the conditions of its aging and the duration of hydrothermal treatment on the particle size distribution for synthesized aluminum orthophosphates have been established. Anhydrous alumophosphate obtained by dehydration of pasty AlPO 4 ·2H 2 O in the temperature range of 150–200 °C with subsequent heat treatment at 900 °C is readily soluble in acids, and the predominant particle size is 5–13 μm.