Extraction of Alumina from Local Clays by Hydrochloric Acid Process@@@إنتاج الألومينا من الطفلة الوطنية بالمعالجة بحامض الأيدروكلوريك
A bench work study was carried out to investigate the use of kaolinitic clay containing 29.4% Al2O3 extremely abundant in Saudi Arabia for the production of pure alumina by calcination at 700 o C for 1h (recommended by previous investigators) then leached by hydrochloric acid. The effects of leaching temperature (25 o C to boiling temperature), period of activation (10-150 minutes), acid concentration (1M – 6M), particle size (–8 to –200 standard Tyler screen mesh), acid to clay weight ratio (4:1 to 15 : 1ml acid/gm clay) on alumina extraction were investigated. The recommended leaching conditions are: 6 molar for acid concentration at boiling conditions under reflux, one hour for leaching time, –100 mesh standard Tyler screens for particle size of calcined clay and 10 ml acid/gm clay for acid to clay weight ratio. Leaching this local clay sample under these conditions resulted in 32% alumina extraction. Local kaolinitic clay were calcined at temperatures varying between 400 o C and 800 o C at different calcination periods (5 to 120 minutes). The calcined clay was then leached with 3M HCl acid under the above-recommended leaching conditions. The optimum calcination conditions were 600 o C and 1 hour for calcination temperature and time period, respectively. The corresponding alumina extraction from local clay sample is about 63%.
Production Of Liquid Alum Coagulant From Local Saudi Clays
This study was carried out to investigate the use of local clays extremely abundant in the Kingdom for production of liquid alum. Local kaolinitic clay containing 29.4% Al2O3 was ground, activated by calcination and treated with sulfuric acid solution to extract alumina. In the activation step, the effects of grain size of clay, temperature and period of calcination on the extraction of alumina and iron oxide are investigated. Leaching experiments were conducted using the stoichiometric requirement of 40 wt. % H2SO4 for one hour under boiling conditions. Clay samples of particle size ranging from 8 to 200 mesh standard Tyler screens, calcined at different temperatures ranging from 450 to 1000 o C and for different periods ranging from 15 to 180 minutes were used. The results revealed that 90.9% of Al2O3 can be extracted when using -65 mesh clay, calcined at 700 o C for one hour. Experiments on the effect of acid concentration on alumina extraction from clay under the above conditions indicate that 40 wt.% acid is the recommended as it gives high extraction of alumina and at the same time results in free flowing properties of the reaction mixture. Leaching experiments were performed to investigate the effects of acid to clay ratio (50 to 120%) and leaching period (0.25 to 3 hrs) on alumina extraction. The results indicate that 88.6% of Al2O3 could be extracted when using 88.1% of stoichiometric requirement of 40 wt.% acid for two hours leaching period under boiling conditions.
Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromatography-mass spectrometry in plants producing crooked calf disease.
The major alkaloids of lupin plants producing crooked calf disease were identified by tandem gas chromatography-mass spectrometry and infrared analysis. The gas chromatography peak invariably present in teratogenic plants proved to be anagyrine. A minor but irregular contaminant of the peak was α-isolupanine. Other alkaloids present but apparently not associated with crooked calf disease were lupanine and two others that were probably epimethoxylupanine and 5,6-dehydrolupanine.