Di-ammonium hydrogen phosphate for the consolidation of lime-based historic mortars – Preliminary research

2021 ◽  
Vol 48 ◽  
pp. 45-53
Author(s):  
Agnieszka Defus ◽  
Elena Possenti ◽  
Antonio Sansonetti ◽  
Cristina Tedeschi ◽  
Chiara Colombo ◽  
...  
2006 ◽  
Vol 309-311 ◽  
pp. 199-202 ◽  
Author(s):  
Ishikawa Kunio ◽  
Yumiko Suzuki ◽  
Shigeki Matsuya ◽  
Masaharu Nakagawa ◽  
Kiyoshi Koyano

Effects of pH on the transformation of gypsum to apatite in the presence of ammonium hydrogen phosphate was studied using NH4H2PO4, (NH4)2HPO4 and (NH4)3PO4. When set gypsum was immersed to ammonium hydrogen phosphate, pH of the solution decreased regardless of the solution. Although pH of the solution decreased, no significant compositional change was observed when gypsum was immersed in NH4H2PO4. On the other hand, apatite and small amount of dicalcium phosphate anhydrous (CaHPO4) was formed when gypsum was immersed in (NH4)2HPO4 solution. Only apatite was formed when gypsum was immersed in (NH4)3PO4 solution. Although the detailed mechanism for the pH dependent products has not been clarified, one of the causes may be the different thermodynamical difference between gypsum and apatite. We would like to recommend the use of (NH4)3PO4 solution since this provides higher pH and thus larger thermodynamical difference between apatite and gypsum and resulting pure apatite block.


2019 ◽  
Vol 7 (4) ◽  
pp. 63
Author(s):  
Ayesha Khatton ◽  
Mubarak Hossen ◽  
Nayer Sultana ◽  
Mohammad Lutful Ahsan

2021 ◽  
pp. 19-25

The aim of the research is the synthesis of sodium ammonium hydrogen phosphate and sodium dihydrogen phosphate based on purified extraction phosphoric acid. The acid was purified from accompanying impurities by precipitation methods using sodium carbonate and metasilicate, washed burnt phosphoconcentrate, barium carbonate, acid neutralization with gaseous ammonia. Pre-neutralization of the purified solution of monoammonium phosphate with sodium carbonate to the ratio Na2O:P2O5 = 0.44 and subsequent drying at a temperature of 50 °С allows to obtain sodium ammonium hydrogen phosphate tetrahydrate, and at 100 °С sodium dihydrogen phosphate monohydrate. The individuality and purity of the synthesized substances was established by the methods of X-ray diffraction, IR spectroscopy, thermogravimetry and scanning electron microscope.


2013 ◽  
Vol 641-642 ◽  
pp. 285-288
Author(s):  
Gou Sheng Liu ◽  
Yue Long Liu

A non-P2O5 process to prepare ammonium polyphosphate is studied in this paper, the effect of raw materials is investigated. The XRD spectra of synthesized product are studied in detail. Results show that when the ratio of Mono-ammonium hydrogen phosphate to urea is 0.8:1, ammonium polyphosphate form V is the mostly occurrence. The results are informative for controllable preparation of APP in industrial production.


2021 ◽  
Vol 12 (1) ◽  
pp. 45-50
Author(s):  
Nofriyani Nofriyani ◽  
Robeth Viktoria Manurung ◽  
Aminuddin Debataraja ◽  
Indra Dwisaputra

This study describes the development of chemical sensors to detect polypyrrole (PPy) based phosphate sensors in doped di-ammonium hydrogen phosphate (DAP) with thick film technology (TFT). Manufacturing screen-printed carbon electrode (SPCE) with thick film uses alumina substrate provided a more portable, miniature, inexpensive, and reduced use of samples and reagents. Polymer polypyrrole and di-ammonium hydrogen phosphate as sensitive membranes are electrodeposition on carbon electrodes. Characterization has been conducted to see the electrode morphology in scanning electron microscopy (SEM) test, which showed that sensitive material particles were distributed evenly on the surface of the sample and spherical. The energy dispersive spectroscopy (EDS) experiment results showed the atomic composition respectively carbon 86.95 %, nitrogen 6.94 %, oxygen 5.9 %, and phosphate 0.21 %, which were exposed to the electrode. The performance test of electrodes with a phosphate standard solution has proceeded at a concentration between 5 to 100 mg/l, which is measured using the galvanostatic method. The voltage range was from 0.252 to 0.957 V with R2 at approximately 90.265 %. The results of sensor performance were concluded that the electrode was able to detect phosphate ions.


2009 ◽  
Vol 426 (2) ◽  
pp. 118-123 ◽  
Author(s):  
T. V. Safronova ◽  
V. I. Putlyaev ◽  
A. I. Sergeeva ◽  
E. V. Kunenkov ◽  
Yu. D. Tret’yakov

1990 ◽  
Vol 1 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Yasushi Taguchi ◽  
Takao Yamamuro ◽  
Takashi Nakamura ◽  
Naomi Nishimura ◽  
Tadashi Kokubo ◽  
...  

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