scholarly journals Preparation of hydroxyapatite by aqueous precipitation from calcium carbonate and phosphoric acid

2021 ◽  
Vol 1113 (1) ◽  
pp. 012013
Author(s):  
Byeong Woo Lee
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid

Calcium pyrophosphate powder synthesized from phosphoric acid and calcium carbonate

2020 ◽  
pp. 42-48
Author(s):  
Tatiana Safronova ◽  
◽  
Tatiana Shatalova ◽  
Snezhana Tikhonova ◽  
Yaroslav Filippov ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Functional Materials ◽  
Bone Defects ◽  
Thermal Conversion ◽  
Calcium Pyrophosphate ◽  
Molar Ratio

Powders of calcium pyrophosphate Ca2P2O7 in the form of γ- и β-modifications have been produced as a result of thermal conversion of brushite CaHPO4∙2H2O synthesized from phosphoric acid H3PO4 and calcium carbonate CaCO3 at the molar ratio P / Ca = 1.1. The resulting powders can be used for production of various functional materials including biocompatible and bioresorbable ones for the treatment of bone defects.

The Loess Modified Methods for Defending Seismic Loading and its Microstructure Analysis

2013 ◽  
Vol 838-841 ◽  
pp. 1600-1608 ◽  
Author(s):  
Jin Deng ◽  
Lan Min Wang ◽  
Jin Jie Sun
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Dynamic Deformation ◽  
Dynamic Strength ◽  
Seismic Loading ◽  
Loading Test ◽  
Talcum Powder ◽  
Filling Materials ◽  
Seismic Deformation ◽  
Barium Metaborate

Loess with large thickness is widely distributed mainly in Gansu provinces of China. The kind of loess has special microstructure to induce lower dynamic strength and larger seismic deformation. It brings to difficult loess processing challenges for engineering building foundations or high way and railway constructions. The large deformation dangers could induce to serious seismic subsidence, watering deformation or loess landslip. There have been series problems of how to change its natural microstructure for engineering demanded which is major concerned in this paper. We put forward Phosphoric modified methods to treat loess problems. By changing different proportions of adding filling materials, such as Calcium carbonate, barite, talcum powder, and others auxiliaries including phosphoric acid and barium metaborate, found it get to be better effect. It’s dynamic deformation coefficients dropped lower than 2‰. After loading test, the methods prove to be greatly enhanced loading strength and changed its unreasonable microstructure. Because of no toxicity materials be adopted and produced during course, the method can be popularized and applied.

scholarly journals The Influences of Sintering Process on the Characteristics of Corbiculacea (Etok) Shells Based Hydroxyapatite Powder

2021 ◽  
Vol 2071 (1) ◽  
pp. 012007
Author(s):  
M R M Roslan ◽  
N F M Nasir ◽  
N F Mohammad ◽  
C E Meng ◽  
M S Mohamed ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Crystallite Size ◽  
Calcium Hydroxide ◽  
Lattice Parameters ◽  
The Other ◽  
Chemical Solution ◽  
Sintering Process ◽  
Hydroxyapatite Powder

Abstract Hydroxyapatite (HA) powders were prepared via chemical solution through aqueous solution of calcium hydroxide and phosphoric acid. The calcium precursor was extracted from the calcium carbonate of Corbiculacea shells while the phosphate precursor originated from the commercially available phosphoric acid. The final product of HA powders is then manipulated through the sintering process at 500°C while the other sample was used as it is. XRD result shows significant changes in its crystallinity, crystallite size and lattice parameters after the sintering process. By sintering the HA, the crystallite size and crystallinity were increases as much as 6.25% and 5.31% respectively. SEM on the other hand showed different morphology for both sintering and non-sintering HA powders. For the sintering HA, the grains size is higher which is 5.00μm compared to non-sintering HA which is 3.91μm due to the agglomeration.

Synthesis of Calcium Pyrophosphate Powders from Phosphoric Acid and Calcium Carbonate

2021 ◽  
Vol 12 (4) ◽  
pp. 986-992
Author(s):  
T. V. Safronova ◽  
T. B. Shatalova ◽  
S. A. Tikhonova ◽  
Ya. Yu. Filippov ◽  
V. K. Krut’ko ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Calcium Pyrophosphate

scholarly journals SYNTHESIS OF CALCIUM FLUORIDE BY DRY METHOD FROM CALCIUM CARBONATE AND AMMONIUM FLUORIDE

2020 ◽  
Vol 63 (8) ◽  
pp. 81-89
Author(s):  
Sergey V. Ostrovsky ◽  
Andrey G. Starostin ◽  
Igor S. Potapov ◽  
Vyacheslav V. Tumanov ◽  
Konstantin G. Kuzminykh
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Calcium Fluoride ◽  
Hydrofluoric Acid ◽  
Thermal Transformation ◽  
Ammonium Fluoride ◽  
Waste Products ◽  
Basic Product ◽  
Solid Mixture ◽  
Hydrolysis Of

The proposed scheme for producing CaF2 according to the “dry” method is based on the following stages: hydrolysis of hydrofluoric acid to produce white carbon black and a 12-18% NH4F solution and subsequent production of CaF2 from CaCO3 at a temperature of 200-400 °C in a fluidized bed or drum furnace in a continuous mode, while ammonia from the exhaust gas is sent to the stage of hydrolysis of hydrofluoric acid. In the article the features of synthetic calcium fluoride obtaining by the "dry" method from calcium carbonate and ammonium fluoride are studied. It is shown that the heating of the mixture proceeds with a step-by-step decomposition of ammonium fluoride, and decomposition products interact with calcium carbonate forming a synthetic calcium fluoride. These factors determine the behavior of a solid mixture of calcium carbonate and ammonium fluoride under heating, which allows us to evaluate the kinetic factors of the interaction of reagents and products and of their thermal transformation. Conditions of receiving synthetic calcium fluoride from the waste products of phosphoric acid and synthetic calcium carbonate by “dry” method are determined. The calcium fluoride can be recognized as a basic product in solving the problem of the waste catalyst hydrofluoric acid utilization. In the article, the features of synthetic calcium fluoride obtaining by the “dry” method from calcium carbonate and ammonium fluoride are studied.  A synchronous thermal analysis of this mixture was carried out with the analysis of exhaust gases by the IR-Fourier method at samplesheating rates of 1.5 ; 5; 10 °С /min in an air atmosphere. It was shown that heating of this mixture proceeds with stepwise decomposition of ammonium fluoride, the products of which interact with calcium carbonate, form synthetic calcium fluoride. In the first stage, the reactions of calcium carbonate with ammonium fluoride and hydrogen fluoride occur in the kinetic region (Еа = 94.22 kJ/mol), and in the second, the reaction of interaction of CaCO3 and HF (Еа = 30.09 kJ/mol) is limited diffusion of HF to the CaCO3 core in the temperature range of 250-300 °С. These factors determine the behavior a solid mixture of calcium carbonate and ammonium fluoride under heating conditions, which allows us to evaluate the kinetic laws of the process of interaction of reagents and products of their thermal transformation. The conditions for obtaining by “dry” method of synthetic calcium fluoride from waste products of phosphoric acid and synthetic calcium carbonate have been identified, and calcium fluoride can be recognized as the base product in solving the problem of disposal of waste hydrofluoric acid.

scholarly journals Investigation of the Process of Purification of Wet-Process Phosphoric Acid and Production of Concentrated Phosphoric Fertilizers Based on it

2021 ◽  
pp. 1-10
Author(s):  
Gulnoza Kodirova ◽  
Israiljon Shamshidinov ◽  
Boxodir Sultonov ◽  
Rikxsitilla Najmiddinov ◽  
Bakhodir Mamurov
Keyword(s):  
Calcium Carbonate ◽  
Phosphoric Acid ◽  
Technological Parameters ◽  
Phosphate Fertilizers ◽  
High Quality ◽  
Wet Process ◽  
Phosphorus Containing ◽  
Calcium Magnesium ◽  
First Time

Fluoride compounds have the most harmful effects on the environment. The main source of fluoride in the soil is phosphorus-containing fertilizers. Purification of wet-process phosphoric acid (WPPA) from fluorine will significantly reduce its content in phosphorous-containing fertilizers and improve the quality of the resulting products. The aim of the study is to reduce the content of fluorine and sulfates in the wet-process phosphoric acid by introducing calcium carbonate, dolomite or phosphorite into the finished extraction pulp before filtration and obtaining high-quality calcium and magnesium-containing phosphate fertilizers based on it. Phosphates were determined by differential photometric, fluorine – ionometric, calcium, magnesium, aluminum, and iron-complexometric, and sulfates-by weight methods. For the first time, scientifically-based data were obtained on the simultaneous reduction of the content of fluorine and sulfates in WPPA from phosphorites of Central Kyzylkum and the production of calcium-magnesium phosphate fertilizers based on it. Optimal technological parameters of the process of simultaneous defluorination and desulfatation of  WPPA from Central Kyzylkum phosphorites with calcium carbonate, dolomite and washed burnt phosphoconcentrate (WСPC) were found by introducing them into the second section of the extractor, into the finished extraction pulp in the amount of 100% for sulfate binding and 100-150% for fluorine binding, as well as obtaining high-quality products based on purified WPPA. The degree of transition of fluorine to the gas phase and phosphogypsum at a rate of 100-150% of calcium oxide for fluorine binding is 86.2-89.4% and its content in the wet-process phosphoric acid decreases from 1.18% to 0.22-0.29%. At the same time, the SO3 content in the acid decreases from 1.21% to 0.24-0.26%. The filtration rate of the sulfate-phosphate pulp varies slightly and is 807.6-812.6 kg/m2·h by dry residue.

Synthesis of Albumin/DCP Nano-Composite Particles

2007 ◽  
Vol 330-332 ◽  
pp. 239-242 ◽  
Author(s):  
Hajime Ohsawa ◽  
Atsuo Ito ◽  
Yu Sogo ◽  
Atsushi Yamazaki ◽  
Tadao Ohno
Keyword(s):  
Drug Delivery ◽  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Bovine Serum Albumin ◽  
Phosphoric Acid ◽  
Bovine Serum ◽  
Composite Particles ◽  
Phosphate Solution ◽  
Delivery Vehicle ◽  
Nano Composite

Highly disgregated dicalcium phosphate anhydrate (DCP) nanoparticles 240-367 nm in diameter were synthesized by a reaction between calcium carbonate and phosphoric acid. When the DCP nanoparticles were immersed in a supersaturated calcium phosphate solution containing bovine serum albumin (BSA) and ethanol, BSA/DCP nano-composite particles were synthesized through the coprecipitation of BSA on the DCP nanoparticles. BSA was firmly immobilized on the BSA/DCP nano-composite particles. The results of this study suggest that DCP nanoparticles appear to be useful as a drug delivery vehicle.

Studies of Serpulid Tube Formation

1956 ◽  
Vol s3-97 (39) ◽  
pp. 411-419
Author(s):  
R. H. HEDLEY
Keyword(s):  
Calcium Carbonate ◽  
Epithelial Cells ◽  
Phosphoric Acid ◽  
Organic Material ◽  
Ferric Iron ◽  
Tube Formation ◽  
Low Ph ◽  
Basic Dyes ◽  
Histochemical Tests ◽  
Heparin Preparation

Calcium carbonate, in a finely granular form, is secreted into the fold of the peristomial collar by a pair of tubulo-racemose glands in the peristomium. Most of the organic material of the tube is secreted by the ventro-lateral epithelial cells which surround the main ducts of the calcium-secreting glands. These cells are always filled with a basiphil mucigen which contains some free a-glycol groups. This material retains its affinity for basic dyes and for ferric iron at a low pH. The affinity for iron is retained when the pH is low enough to exclude carboxyl and phosphoric acid groups from the reaction and it is probable that the sulphuric acid groups are responsible. The reactions of this mucigen to histochemical tests together with the similarity in behaviour of a precipitated heparin preparation make it likely that the material is a sulphomucopolysaccharide.

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