scholarly journals PURIFICATION OF PHOSPHOGYPSUM FOR USE AS CEMENT RETARDER BY SULPHURIC ACID TREATMENT

2020 ◽  
Vol 58 (3A) ◽  
pp. 32
Author(s):  
Dang Ngoc Phuong ◽  
Ngo Kim Chi ◽  
Tran Dai Lam ◽  
Chu Quang Truyen ◽  
Tran Trung Kien ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Calcium Sulfate ◽  
Diammonium Phosphate ◽  
Chemical Compositions ◽  
Sulfuric Acid Treatment ◽  
Toc Removal ◽  
Cement Retarder ◽  
Lao Cai ◽  
Phosphogypsum Waste

Phosphogypsum is a by-product of the wet phosphoric acid production. In this study, chemical compositions of phosphogypsum waste (PG) in Hai Phong diammonium phosphate plant (DAP1) and Lao Cai diammonium phosphate plant (DAP2) in Vietnam were surveyed for the purpose of gypsum recovery by P2O5, F removal to meet TCVN11833 for use treated gypsum as cement retarder. Studies of impurities P2O5, F, TOC removal by sulfuric acid 10 % at 28 0C was presented. The results found that the combination of a low concentration of sulfuric acid treatment, washing, lime neutralizing, and thermal treatment was successful in Phoshogypsum treatment for use as cement retarder. The cement test proved that treated PG could partially replace natural gypsum as a retarder.Keywords:  phosphogypsum treatment, phosphorus pentoxide removal, calcium sulfate transition phase, cement retarder. 

scholarly journals Effect of Sulfuric Acid Treatment and Calcination on Natural Zeolites of Indonesia

2016 ◽  
Vol 28 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Ady Mara ◽  
Karna Wijaya ◽  
Wega Trisunaryati Mudasir
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Natural Zeolites ◽  
Sulfuric Acid Treatment

Cyclodiene Chemistry. III. Derivative Formation for the Identification of Heptachlor, Heptachlor Epoxide, cis-Chlordane, irans-Chlordane, Dieldrin, and Chromatography

1969 ◽  
Vol 52 (6) ◽  
pp. 1220-1226 ◽  
Author(s):  
Alfred S Y Chau ◽  
W P Cochrane
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Heptachlor Epoxide ◽  
Improved Method ◽  
Sulfuric Acid Treatment ◽  
Subsequent Conversion ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed ◽  
Cis And Trans ◽  
Feed Samples

Abstract An improved method, involving potassium tert.-butoxide and tert.-butanol treatment followed by acetylation, is described for the similtaneous confirmation of heptachlor, heptachlor epoxide, and cis- and trans-chlordanes in cleaned-up feed samples. Parent pesticide residues can be identified at levels of 0.01 ppm and above. As a confirmative test for dieldrin, the formation of an acetate and subsequent conversion to a “ketone” by acetic anhydride/ sulfuric acid treatment is used. The concentrated sulfuric acid-catalyzed isomerization of endrin is also reported.

Preparation of Low-Sulfur Expanded Graphite with Different Size Particles

2013 ◽  
Vol 652-654 ◽  
pp. 745-748 ◽  
Author(s):  
Chun Yu Wang ◽  
Huan Ran Li ◽  
Chun Lin Qin ◽  
Peng Zhang
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Acid Treatment ◽  
Engineering Application ◽  
Expanded Graphite ◽  
Mixture Ratio ◽  
Sulfuric Acid Treatment ◽  
Low Sulfur

In this paper, results shows that expanded graphite of 128mL/g could be produced under the nitric acid treatment with the optimum mixture ratio of graphite: HNO3: H2O2: KMnO4 being 1(g):6(ml):2(ml):0.02(g), compared with the 145ml/g under the sulfuric acid treatment (graphite: H2SO4: H2O2 =1(g):3(ml):2 (ml)). The sulfur contents are ~0.10wt.% in EG with nitric acid treatment, and ~0.24wt.% in EG with sulfuric acid treatment, respectively. Therefore, the nitric acid treatment EG has little sulfur, which is greatly demanded in engineering application.

Integrated technology of sulfuric acid treatment for eudialyte concentrate

2018 ◽  
pp. 20-27
Author(s):  
V. A. Matveev ◽  
◽  
D. V. Mayorov ◽  
A. V. Solovev ◽  
◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Sulfuric Acid Treatment ◽  
Integrated Technology ◽  
Eudialyte Concentrate

scholarly journals Polyol-Free Synthesis of Uniformly Dispersed Pt/Graphene Oxide Electrocatalyst by Sulfuric Acid Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Tae Kyu Lee ◽  
Hyang Jin Park ◽  
Min Ki Kwon ◽  
Ju Hae Jung ◽  
Junbom Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Sulfuric Acid ◽  
Acid Treatment ◽  
Pt Nanoparticles ◽  
Hydroxyl Groups ◽  
Electrochemical Surface Area ◽  
Surface Hydroxyl ◽  
Sulfuric Acid Treatment ◽  
Surface Hydroxyl Groups ◽  
Loading Amount

Polyol-free synthesis of highly loaded Pt catalysts on sulfuric-acid-treated graphene oxide (SGO) was reported. Sulfuric acid treatment increased the surface hydroxyl groups on graphene oxide (GO), which contributed to the reduction of Pt precursors in the absence of external reducing agent. By adjusting pH during the Pt reduction, we can get uniformly dispersed 2.5 nm size Pt nanoparticles on GO surface even at 50 wt% Pt loading amount. Cyclic voltammetry showed that increased pH resulted in increased electrochemical surface area.

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