Utilization of ferrous leach liquor to synthesize gamma ferric oxide

The production of pigment grade titanium dioxide involves leaching of ilmenite with acids that also results in the formation of ferrous sulfate/chloride. Usually the ferrous salts are spray-roasted to regenerate the sulfuric acid/hydrochloric acid for recycling. However, the quantities of ferrous leach liquor and the capital cost of the regeneration plant dictate the viability of regeneration of acids, In the case of smaller ilmenite processing plants, the regeneration of the acid is not economical and warrants alternate methods of using the ferrous leach liquor, The present paper describes a novel method of synthesizing gamma ferric oxide from ferrous leach liquor obtained from a titanium dioxide pigment plant situated in south India. The partial precipitation technique is employed to purify the ferrous leach liquor and make it suitable for the synthesis. Sodium carbonate is used to precipitate iron as ferrous carbonate and is directly calcined to yield gamma ferric oxide. Experiments were conducted to study the effect of heating rate, condition of the precipitate, whether dry or wet, and extent of oxidation of ferrous on the magnetic properties such as coercivity and specific magnetization. Cobalt-doped gamma ferric oxide was also prepared by the carbonate precipitation route

Bisphenol-A and the Great Divide: A Review of Controversies in the Field of Endocrine Disruption

In 1991, a group of 21 scientists gathered at the Wingspread Conference Center to discuss evidence of developmental alterations observed in wildlife populations after chemical exposures. There, the term “endocrine disruptor” was agreed upon to describe a class of chemicals including those that act as agonists and antagonists of the estrogen receptors (ERs), androgen receptor, thyroid hormone receptor, and others. This definition has since evolved, and the field has grown to encompass hundreds of chemicals. Despite significant advances in the study of endocrine disruptors, several controversies have sprung up and continue, including the debate over the existence of nonmonotonic dose response curves, the mechanisms of low-dose effects, and the importance of considering critical periods of exposure in experimental design. One chemical found ubiquitously in our environment, bisphenol-A (BPA), has received a tremendous amount of attention from research scientists, government panels, and the popular press. In this review, we have covered the above-mentioned controversies plus six additional issues that have divided scientists in the field of BPA research, namely: 1) mechanisms of BPA action; 2) levels of human exposure; 3) routes of human exposure; 4) pharmacokinetic models of BPA metabolism; 5) effects of BPA on exposed animals; and 6) links between BPA and cancer. Understanding these topics is essential for educating the public and medical professionals about potential risks associated with developmental exposure to BPA and other endocrine disruptors, the design of rigorously researched programs using both epidemiological and animal studies, and ultimately the development of a sound public health policy