Total and soluble oxalate content levels were measured in thirteen selected vegetables purchased from a local market in Surin Province in the northeast of Thailand. Total oxalate contents of the leaves, shoots and roo...Total and soluble oxalate content levels were measured in thirteen selected vegetables purchased from a local market in Surin Province in the northeast of Thailand. Total oxalate contents of the leaves, shoots and roots of the fresh vegetables ranged from 249.5 ± 12.1 to 7597.9 ± 77.6 mg oxalate/100g dry matter (DM) while soluble oxalate content ranged from 205.0 ± 2.3 to 2677.6 ± 19.0 mg oxalate/100 g DM. Very high levels of total oxalates were found in three of the selected Thai vegetables, Polygonum odoratum (7597.9 ± 77.6 mg/100g DM), Piper aurantaucum (7026.6 ± 76.9 mg/100g DM) and Limnophila aromatic (6179.0 ± 23.6 mg/100g DM). However, the soluble oxalate content of L. aromatic was low and the highest soluble oxalate contents of fresh vegetables were found in P. odoratum, P. aurantuacum and Neptunia oleracea at 2677.6 ± 19.0, 2152.2 ± 65.3 and 1640.8 ± 3.4 mg/100g DM, respectively. Boiling the vegetables reduced the soluble oxalate content between 30.4 and 65.0%. The insoluble oxalate levels increased in eleven of the cooked vegetables while small decreases were observed in L. aromatic and N. oleracea.展开更多
Titanium dioxide （TiO2） was recovered from ilmenite （FeO-TiO2） contained in ferrotitaniferous sands of Mompiche area, by the combination of the thermal treatments of oxidation and carbothermic reduction and the su...Titanium dioxide （TiO2） was recovered from ilmenite （FeO-TiO2） contained in ferrotitaniferous sands of Mompiche area, by the combination of the thermal treatments of oxidation and carbothermic reduction and the subsequent leaching with hydrochloric acid （HCI） of the thermally treated samples. This study was developed because of the large source of TiO2 that Ecuador has, but has not developed enough research to place an industry to produce this compound. The oxidation at 900 ℃ for 3 h yielded a content of 11% of TiO2, and the highest oxidation of ilmenite （82%） was achieved at 1,000 ℃ for 1 h. The carbothermic reduction with 15wt% carbon at 950 ℃ for 2 h achieved a content of 6% TiO2 and 21% ilmenite. The combination of thermal treatments did not increase the content of TiO2 but allowed to obtain more soluble minerals in HCl. The best results of leaching were obtained with 100 mL of 256 g/L HC1 for 6 h at 70 ℃ and 10% solids of the sample oxidized at 900 ℃ for 3 h and subsequently reduced with 15wt% carbon at 950 ℃ for 2 h. The optimum leaching time was 4 h, giving a TiO2 of 90% purity with a recovery of 43%.展开更多
文摘Total and soluble oxalate content levels were measured in thirteen selected vegetables purchased from a local market in Surin Province in the northeast of Thailand. Total oxalate contents of the leaves, shoots and roots of the fresh vegetables ranged from 249.5 ± 12.1 to 7597.9 ± 77.6 mg oxalate/100g dry matter (DM) while soluble oxalate content ranged from 205.0 ± 2.3 to 2677.6 ± 19.0 mg oxalate/100 g DM. Very high levels of total oxalates were found in three of the selected Thai vegetables, Polygonum odoratum (7597.9 ± 77.6 mg/100g DM), Piper aurantaucum (7026.6 ± 76.9 mg/100g DM) and Limnophila aromatic (6179.0 ± 23.6 mg/100g DM). However, the soluble oxalate content of L. aromatic was low and the highest soluble oxalate contents of fresh vegetables were found in P. odoratum, P. aurantuacum and Neptunia oleracea at 2677.6 ± 19.0, 2152.2 ± 65.3 and 1640.8 ± 3.4 mg/100g DM, respectively. Boiling the vegetables reduced the soluble oxalate content between 30.4 and 65.0%. The insoluble oxalate levels increased in eleven of the cooked vegetables while small decreases were observed in L. aromatic and N. oleracea.
文摘Titanium dioxide （TiO2） was recovered from ilmenite （FeO-TiO2） contained in ferrotitaniferous sands of Mompiche area, by the combination of the thermal treatments of oxidation and carbothermic reduction and the subsequent leaching with hydrochloric acid （HCI） of the thermally treated samples. This study was developed because of the large source of TiO2 that Ecuador has, but has not developed enough research to place an industry to produce this compound. The oxidation at 900 ℃ for 3 h yielded a content of 11% of TiO2, and the highest oxidation of ilmenite （82%） was achieved at 1,000 ℃ for 1 h. The carbothermic reduction with 15wt% carbon at 950 ℃ for 2 h achieved a content of 6% TiO2 and 21% ilmenite. The combination of thermal treatments did not increase the content of TiO2 but allowed to obtain more soluble minerals in HCl. The best results of leaching were obtained with 100 mL of 256 g/L HC1 for 6 h at 70 ℃ and 10% solids of the sample oxidized at 900 ℃ for 3 h and subsequently reduced with 15wt% carbon at 950 ℃ for 2 h. The optimum leaching time was 4 h, giving a TiO2 of 90% purity with a recovery of 43%.
