Precipitation Process of Calcium Phosphate from Calcium Carbonate Suspension

Abstract

The Ca-HA is synthesized by reacting calcium carbonate (CaCO 3 ) and ammonium dihydrogen orthophosphate (NH 4 H 2 PO 4 ) in stoichiometric proportions. In this precipitation process, the ratio of Ca/P by moles is 1.67. The experiments were performed in a batch reactor at 25 °C. From control parameters, the pH and the temperature were measured in line for all experiments. The tests were performed with two liquid-solid mass ratios (H 2 O/ CaCO 3 ) of 3 and 5. For each mass ratio, three stirring rates of 260, 400, and 600 rpm were tested. Samples of the synthesis were collected at different intervals and analysed by laser granulometry and by environmental scanning electron microscopy. For the synthesis conducted at 260 rpm, synthesis monitoring was made using a contact probe in solution coupled to a Raman spectrometer in order to follow the formation of solid phase. This technique is valuable to follow the synthesis of Ca-HA in a concentrated solids suspension (around 20-30 wt%). The results make it possible to propose a mechanism of the precipitation process of Ca-HA. It can be divided into four main stages: (i) dissolution of calcium carbonate (CaCO 3 ), (ii) precipitation of brushite (CaHPO 4 .2H 2 O), (iii) transformation of brushite into Ca-HA (Ca 10 (PO 4 ) 6 (OH 2 )) and (iv) nucleation, growth and agglomeration of Ca-HA.

Crystallization of carboplatin-loaded onto microporous calcium phosphate using high-vacuum method: Characterization and release study

“…The dissolution-precipitation method from calcium carbonate suspension as calcium source aims to reduce steps in the process such as the previous calcination of calcium carbonate to calcium oxide, washes, and purification [59]. The composition and morphological characteristics of calcium phosphate by aqueous precipitation using calcium carbonate, as the same as other calcium sources, are a result of the reaction conditions, especially temperature, acid addition rate, and reaction time [60][61][62]. This work used ultrasonic irradiation to achieve microporous powder of hydroxyapatite and β-TCP after calcination.…”

Obtaining hydroxyapatite with different precursors for application as a biomaterial

“…Among the calcium phosphate bioceramics, the hydroxyapatite (HAp) [17,[22][23][24] is highlighted in the research area because it is similar to main mineral phase constituent of the bone, with a wide use in the medical and dental areas [25][26][27]. HAp is a calcium phosphate hydrated from the mineral group of apatite with chemical formula Ca 10 (PO 4 ) 6 (OH) 2 and Ca/P ratio of 1.67 [3,28]. It is a bioactive ceramic material widely used in the form of particles in several devices of the bone regeneration Resumo A hidroxiapatita (HAp) é um biomaterial cerâmico com ampla aplicação na regeneração óssea.…”

Influência da incorporação da HAp e β-TCP no cimento ósseo wollastonita/brushita

“…A HAp é um fosfato de cálcio hidratado do grupo mineral das apatitas de fórmula química Ca10(PO4)6(OH)2 e razão Ca/P igual a 1,67 [26,27]. Pode-se destacar também o fosfato tricálcico-TCP (Ca3(PO4)2) um biomaterial de grande importância, pois, como todos os fosfatos de cálcio, apresenta similaridade com a fase mineral de ossos e dentes; além de sua excelente biocompatibilidade; bioatividade e ausência de toxicidade local [28].…”