Development of Simple Low Cost Techniques for Recovery of Value Added Metals Causing Industrial Pollution

Abstract

<span style="font-size:12.0pt;line-height: 115%;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" color:black;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="" lang="EN-US">Heavy metals are important constituents of industrial effluents, ore wastes and fly ash. Although some of them are essential for living organisms, their accumulation at one place becomes a source of environmental pollution and threatens the health of living beings. Nickel, molybdenum and chromium are such metals which enter the environment through industrial wastes and it is important to reduce their concentration from the industrial wastes. Taking this into consideration, attempt has been made to analyse and recover these metals from the industrial ore wastes, viz. 'Acid pickling sludge', from Steel Authority of India Ltd, Durgapur and Salem plants. The dried powdered sludge is digested with acid and analysed for these metals by atomic absorption spectroscopy. The samples are then separately subjected to leaching in dilute acetic acid, ammonium hydroxide and neutral medium and the leachates are analysed for the same metals. The results demonstrate that mobilization of metals is more likely in dilute acids and it is possible to recover these metals by simple techniques from industrial wastes. Also, the physical properties of the ore wastes collected from two plants seems to be different which might have resulted in the difference in recovery of molybdenum from acidic or alkaline medium from different sources.</span>