DETOXIFICATION OF HAZARDOUS WASTE CONTAINING MERCURY and ITS COMPOUNDS BY OXIDATION WITH FREE CHLORINE
Released on = February 27, 2006, 3:53 am
Press Release Author = Ms. Papita Saha
Industry = Chemicals
Press Release Summary = A number of Chloro - Alkali Industries in India was the conventional but outdated Mercury Cell process. These industries generate a large quantity of solid wastes containing elemental mercury & chlorinated mercury compounds. Disposal of this solid waste is still a difficult problem for these Industries. Investigations were carried out using free Chlorine in alkaline medium as reagents for dissolution of mercury into the aqueous medium for detoxification of the waste sludge and subsequently the recovery of Mercury from aqueous medium. Mercury present in sludge could be brought down from 130 mg/kg to 15.5 mg/kg by Chlorine treatment. This process is cost effective and technically feasible as Chlorine gases are produced at Chloro - Alkali Plants and it is rejected as istage in Chloro Alkali Plant.
Press Release Body = A large quantity of solid wastes containing mercury and chlorinated mercury compounds is generated from Chloro Alkali Industries(1) for the production of sodium hydroxide and chlorine. In Chloro Alkali Industry mercury is used as a liquid cathode. During electrolysis, the sodium liberated at Mercury cathode immediately dissolved in mercury, forming amalgam. Chlorine evolved at the graphite, electrodes rises through the electrolyte and fills the space over the brine and is piped out. The amalgam is treated with deionised water in the decomposer unit to form sodium hydroxide and hydrogen. The flow rate of water is regulated so as to decompose almost all the amalgam and to obtain 45 - 51%caustic lye. Mercury ions in environment are non- - biodegradable and once ingested, metal ions accumulate into the organs which often-resulting death. Besides the economical reason, loss of Mercury has a role in the environment pollution. In our country the brine sludge is kept in the large pits without any treatment or protection. As a result at the time of rainwater, Mercury and its salts mixed with the surface living beings. Mercury and its salts are so toxic that it causes tremor, irritability, slurred speech and blindness. The kidney is the main target organ for inorganic mercury. It is a protoplasmic poison and damages the central nervous system. Mercury vapor is toxic and if inhaled cause giddiness, tremors, lung damage, brain damage. MercuryII inhibits enzymes, particularly those containing thiol groups. There are different techniques for removing Mercury from the brine sludge, like chemical oxidation and consequent formation of soluble Mercury salt. But our study is confined within the chemical oxidation and complex formation of dissolved Mercury in aqueous phase from brine sludge. The variables on which treatment of Mercury sludges depend are:Chlorination on Mercury Recovery, Agitation on Mercury Recovery, Temperature on Mercury Recovery From the experimental study it is observed that at pH 12.5, agitation time 40 minutes, temperature range 500C to 750C, % recovery of mercury is 88.05% and Mercury present in sludge can be brought down from 130 mg/kg to 15.5 mg/kg.
Web Site = http://geocities.com/papitasaha
Contact Details = Papita Saha. LecturerBiotechnology Dept ITME College West Bengal IndiaE-mail: firstname.lastname@example.org, email@example.com