Crystallization of single and binary iron- and aluminum hydroxides affect phosphorus desorption

2019 ◽  
Vol 182 (5) ◽  
pp. 741-750 ◽  
Author(s):  
Stella Gypser ◽  
Elisabeth Schütze ◽  
Dirk Freese
Author(s):  
A.M. Semiletov ◽  
◽  
Yu.B. Makarychev ◽  
A.A. Chirkunov ◽  
L.P. Kazansky ◽  
...  

The application of mixed corrosion inhibitor (CI), which is an equimolar composition of oleoyl sarcosinate (SOS) and sodium flufenamate (SFF), for protection of D16 aluminum alloy from atmospheric corrosion has been studied. The polarization measurements used to assess the effectiveness of preliminary passivation of the alloy with solutions of SOS, SFF and their composition showed significant advantages of mixed CI. The XPS method was used to study features of CI adsorption on the surface of D16 alloy. It has been established that upon adsorption of SOS and SFF separately a monolayer is formed, firmly bonded to the alloy surface, thickness of which is not exceeding 2.6—3.2 nm. After the joint adsorption of these CI, the layer thickness reaches 12—20 nm. The composition of this layer includes a considerable amount of Al3+ ions (~20%) related to their compounds with SFF and SOS, as well as to aluminum hydroxides. A possible mechanism for the formation of such a protective layer is proposed. The results of corrosion tests in a humid atmosphere with daily water condensation on samples of D16 alloy confirmed the high protective ability of the mixed CI film.


1999 ◽  
Vol 33 (3) ◽  
pp. 769-777 ◽  
Author(s):  
Jerzy Lukasik ◽  
Yueh-Fung Cheng ◽  
Fuhua Lu ◽  
Mark Tamplin ◽  
Samuel R. Farrah
Keyword(s):  

2021 ◽  
Vol 223 ◽  
pp. 246-256
Author(s):  
Wang Li ◽  
Bo Zu ◽  
Qingwei Yang ◽  
Jun Wang ◽  
Jiawen Li

2021 ◽  
Author(s):  
M. Hauer ◽  
M. Meyer ◽  
D. Billieres ◽  
C. Bricquet ◽  
F. Gerstgrasser ◽  
...  

Abstract This study assesses the quality of flame-sprayed alumina coatings produced from recently developed alumina cord using argon and compressed air as atomizing gases. Coatings of different thicknesses were deposited on aluminum substrates and then analyzed using optical microscopy, X-ray diffraction, and resistivity measurements. The coatings, particularly those sprayed with argon, had fine microstructure and higher surface and volume resistivity than flame-spray coatings made from alumina cord in the past. They were also found to have higher alpha phase content than plasma-sprayed coatings, regardless of the atomizing gas used. The effect of humidity and the possible formation of aluminum hydroxides are also addressed.


Soil Science ◽  
2008 ◽  
Vol 173 (10) ◽  
pp. 683-693 ◽  
Author(s):  
Ren-kou Xu ◽  
Leonard Myrell Kozak ◽  
Pan Ming Huang

2001 ◽  
Vol 65 (9) ◽  
pp. 1391-1398 ◽  
Author(s):  
Frédéric Vitali ◽  
Fred J Longstaffe ◽  
Michael I Bird ◽  
Karie Lyne Gage ◽  
W.Glen E Caldwell

Soil Science ◽  
2006 ◽  
Vol 171 (9) ◽  
pp. 695-705 ◽  
Author(s):  
Shinjiro Sato ◽  
Nicholas B. Comerford

2005 ◽  
Vol 29 (5) ◽  
pp. 685-694 ◽  
Author(s):  
Shinjiro Sato ◽  
Nicholas Brian Comerford

Liming is a common practice to raise soil pH and increase phosphorus (P) bioavailability in tropical regions. However, reports on the effect of liming on P sorption and bioavailability are controversial. The process of phosphorus desorption is more important than P sorption for defining P bioavailability. However few studies on the relationship between soil pH and P desorption are available, and even fewer in the tropical soils. The effects of soil pH on P sorption and desorption in an Ultisol from Bahia, Brazil, were investigated in this study. Phosphorus sorption decreased by up to 21 and 34 % with pH increases from 4.7 to 5.9 and 7.0, respectively. Decreasing Langmuir K parameter and decreasing partition coefficients (Kd) with increasing pH supported this trend. Phosphorus desorption was positively affected by increased soil pH by both the total amount of P desorbed and the ratio of desorbed P to initially sorbed P. A decreased K parameter and increased Kd value, particularly at the highest pH value and highest P-addition level, endorsed this phenomenon. Liming the soil had the double effect of reducing P sorption (up to 4.5 kg ha-1 of remaining P in solution) and enhancing P desorption (up to 2.7 kg ha-1 of additionally released P into solution).


2021 ◽  
Vol 5 (1) ◽  
pp. 53
Author(s):  
Andriani Manataki ◽  
James M. Mwase ◽  
Casper van der Eijk

The Pedersen process is an alumina production process, which combines pyrometallurgical and hydrometallurgical methods. In the pyrometallurgical stage, limestone is calcined and CO2 is generated. This off-gas can be captured with a high CO2 concentration. At the end of the hydrometallurgical process, aluminum hydroxides, like bayerite, are precipitated using CO2. In this paper, experimental work on precipitation of aluminum hydroxides through the addition of a mixture of CO2, O2 and N2 is presented. The parameters varied, as were the percentages of each gas and the temperature. The indicators measured were the time until the beginning of precipitation and the time that the precipitation lasts. These tests simulate the use of a smelter furnace off-gas in the precipitation stage of the Pedersen process and have shown promising results.


2002 ◽  
Vol 52 (3) ◽  
pp. 223-230 ◽  
Author(s):  
Akiko UCHIDA ◽  
Takushi YOKOYAMA ◽  
Yoshinobu MOTOMURA ◽  
Akane MIYAZAKI ◽  
Yoshihiro OKAUE ◽  
...  
Keyword(s):  

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