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Showing 2 results for Calcium Sulfate
Volume 1, Issue 1 (3-2023)
Abstract
The dust produced by the electric arc method in the ferrochrome factory contains high amounts of hexavalent chromium, which has a high solubility in water and causes high environmental pollution. The present research has proposed a new method for neutralization of hexavalent chromium present in ferrochrome dust in solution environment by using chemical precipitation method. After checking conventional and non-conventional additives for neutralization by co-precipitation method, Iron sulfate is added to the aforementioned wastewater before release into the environment as a reducing agent of hexavalent chromium to trivalent chromium. Next, calcium sulfate was used as a stable complex forming factor in the system to remove chromium. XRD and XRF analyzes were used to characterize the dust and UV-Visible to determine the amount of chromium removed from the wastewater. The results showed that for 100 g/l of dust dissolved in water, adding 30 g of iron sulfate in the first stage and 20 g of calcium sulfate in the second stage reduces the content of hexavalent chromium from high values to below 10 ppm. Easy, high speed, cheapness and availability of additives are the merits of this method.
Volume 3, Issue 11 (12-2006)
Abstract
Adequate calcium ( Ca ) intake during the crucial growing years maximizes peak bone mass and thus delays the onset of osteoporosis later in life. In addition, Ca plays a protective role against essential hypertension and colorectal cancer. Dairy products, a naturally rich Ca source, are the major source of Ca in our diet. However many people avoid consuming milk, because of economical problems and who are lactose intolerant. For these people, Cafortified nondairy foods can be a significant source of Ca. A number of foods, including bread, staple food, can be fortified with Ca. In this study, formulation and production of fortified Barbari bread with different Ca sources was investigated. In order to, different kind of Barbari breads were prepared with flour fortified with two food-grade inorganic Ca sources such as Ca carbonate and Ca sulfate. Ca was added to flour at two levels: 500 and 1000 mg/ 100 g of flour. one bread was also prepared using ordinary flour. Results of Farinograph and Extensograph tests indicated strength of dough. Results of Farinograph test indicated that the percent of absorbed water, dough development time, dough stability and valorimeter value will increase by adding Ca, while the degree of dough softening in 10 and 20 minates, will reduce. Also atomic absorption spectrophotometry test showed that retaining of Ca in breads was significant ( P< 0.01).CaCO3 and CaSO4 are preffered sources of Ca for the fortification of cereal-based foods as they had no adverse affect on bread quality but CaCO3 is higher in Ca than CaSO4. It is also less expensive. For these reasons, Ca carbonate is a preffered Ca source for fortifying bread.