ChemInform Abstract: Thermolysis of Dihydrogen Phosphates of Bivalent Metals.

Study of bishofite–phosphate acid interaction in the aqueous solution

“…The dependence of рН of filtration solutions of one of the cross section [11]is possible in exploratory conditions. At high pH values~9,5 magnesium hydroxyapatite of low solubility, at pH~9,0 and less in the alkaline area -ammonium magnesium phosphate, at рН~4,7 -6,0 -magnesium hydrogen phosphate [2], at рН less than 4,5-magnesiumdihydrogenphosphatecan becomposed.…”

“…Introduction. Bishofite [1] which main compoundismagnesiumchlorideisusedas an accessible and natural raw material in order to get ammonium magnesium phosphates of various composition during fertilizer [2],antipyrene[3]productionand otherproduction.…”

“…It was also described in [4] how these complex fertilizers in the form of NH 4 MgPO 4 • хН 2 О were got. The detailed analysis of range of publications was presentedin [2],andin [5][6][7],whereitwas informedaboutvarioussynthesisconditions of ammonium magnesium phosphates as well as results of their study by means of thermalgravimetricandX-rayphaseanalysis. The data received by various authors in thesepapersdon'tcorrespondtoeachother.…”

“…The data received by various authors in thesepapersdon'tcorrespondtoeachother. This is particularly true for chemical compounds, X-ray characteristics as well as for interpretation of thermal gravimetric dataonthebasisofwhichsomeauthorssay that NH 4 MgPO 4 is decomposed into NH 3 and MgHPO 4 , and other authorsinto NH 3 , Н 2 О and Mg 2 P 2 O 7 [2]; according to someresearchers,thisprocessiscarriedout becauseofcompositionofmagnesiumoxide and polyphosphates which compose Mg 2 P 2 O 7 [7]athighertemperatures. Theknownmagnesiumandammonium phosphates were got by various authors mostly from laboratory reagents, the synthesisofthesesubstanceswiththeuseof natural bishofite within a wide range of given[РО 4 3-]:[Мg 2+ ]ratioswasnotstudied.…”

“…In the fig. 3 In order to study the nature of got precipitationstheywerestudiedbymeansof X-rayphaseanalysis( fig.4) [2] and [5] by means of the same methodscanbeexplained.…”