Title of Invention | A PROCESS FOR THE SEPARATION OF IRON FROM ZIRCON" |
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Abstract | An improved process for the separation of iron from zircon which comprises treating zircon with a solution of oxalic acid having strength ranging 0.2 to 1.08/100 ml of water and the ratio of zircon: oxalic acid is in the range of 1:10 to 1:30 by weight/volume, for a period of 3 to 4 days at ambient temperature and pressure, recovering zircon by conventional leaching of oxalic acid. |
Full Text | This invention relates to an improved process for the separation of iron from zircon The process of the present invention particularly relates to a chemical method which removes iron from zircon. The process is economical and pollution free. Zircon (ZrSi04) is one of the most important minerals of zirconium. Zircon is used as an abrasion resistant, high temperature refractory material. Finely powdered zircon finds use as an opacifier in ceramic and as a lining material for moulds used for precision casting of metals. Zircon oxide and other compounds of zirconium have many industrial application. High purity zirconium oxide is used in the production of quality refractory and artificial diamonds known as American Diamonds. Ziroon metal has good corrosion resistant properties. One of its modern applications is its use as a cladding material for nuclear fuel in power reactors and manufacture of corrosion resistant compounds of nuclear reactors, and corrosive insulations in chemical plants. Zirconium metal is also used for manufacture of flash bulb. Zircon flour is used for the manufacture of CEM-fill fibre which is an alkali resistant glass fibre used for reinforcing cement in building and construction industries. Zircon is also in great demand in steel industry for lining steel ladles. There is a possibility of use of toughened zirconia (Zr02) in the advanced diesel engine because of it excellent wear resistance and strength. India has a rich reserve of zircon. As per Indian Bureau of mines recoverable reserves of zircon in India as on 1st April 1990 was 1.2 million tonnes. Presently, zircon is recovered, at four plants, three of them are owned by Indian Rare Earth Limited (IRE) and fourth is of Kerala Thermal & Metals Ltd. (KTML). They together produced 15,095 tonnes of zircon in 1989-90 as compared with 23,899 tonnes in 1988-89. IRE's Orissa Sand Complex (OSCOM), situated ar Chatrapur, produced 200 tonnes in 1988-89 and 1118 tonnes in 1989-90 against the capacity of 2000 tonnes per anum. Zircon particles are coated with oxides of iron. OSCOM zircon contains 0.27 % Fe203 This causes difficulty in its industrial utilization particularly in the glass & ceramic industry. The intrinsic value of zircon sand is dependent upon not only the zirconia (Zr02) content but also on the content of iron therein. Iron imparts brownish tinge in zircon. Depending upon zirconia and iron content zircon is classified in three categories for marketing purpose, viz. (a) Standard foundary grade containing a minimum of 65 % Zr02, (b) Intermediate grade containing 65.5 to 66 % Zr02 and 0.06 to 0.1 X Fe2O3 and (c) Premium Grade containing 66 % Zr02 and maximum of 0.5 % Fe203. International price difference between Standard Grade Zircon and Premium Grade Zircon ranges between $ 15 to 20 per tonne fob. Thus, it is always beneficial for the producers to remove iron from zircon before export. The existing normal practice of getting rid of iron is to treat the zircon with hydrochloric acid at elevated temperature. But this process results in corrosion of reactors by hydrochloric acid and also causes pollution in the atmosphere. Electron beam melting of zirconium has been used to remove the more volatile impurities such as iron, but the relatively high volatility of zirconium precludes effective purification. Electrorefining in fused salt baths and purification by d-c electrotransport have been demonstrated but not in commercial use. The object of the present invention is to provide an improved process for the separation of iron from zircon which obviates the draw backs of the hitherto known process. Accordingly the present invention provides an improved process for the separation of iron from zircon which comprises treating zircon with a solution of oxalic acid having strength ranging 0.2 to 1.08/100 ml of water and the ratio of zircon: oxalic acid is in the range of 1:10 to 1:30 by weight/volume, for a period of 3 to 4 days at ambient temperature and pressure, recovering zircon by conventional leaching of oxalic acid. The oxalic acid used may be of commercial grade an may be of concentration in the range of 0.2 to 1.0 % preferable concentration may be 0.4g/100ml. The ratio of zircon : oxalic acid solution may be in the range of 1: 10 to 1:30 by weight/volume. The treatment may be effected at ambient temperature and pressure under agitation/stationary condition. The following examples are given by way of illustration and should not be construed to limit the scope of the invention. Example 1:- Zircon was treated with a solution of 0.4 wt % commercially available oxalic acid in water in the ratio of 1:10 (zircon : oxalic acid solution) at ambient temperature and pressure under agitation. Within 4 days of residence time about 80% of iron associated with zircon containing 0.27 % Fe2 03 gets successfully leached out from zircon leaving a totally white coloured zircon. Example 2:- 1kg. Zircon was taken in 10 litre of 0.4% of commercial oxalic acid solution in a bucket of 15 litre capacity. The whole was We claim :- 1. An improved process for the separation of iron from zircon which comprises treating zircon with a solution of oxalic acid having strength ranging 0.2 to 1.08/100 ml of water and the ratio of zircon: oxalic acid is in the range of 1:10 to 1:30 by weight/volume, for a period of 3 to 4 days at ambient temperature and pressure, recovering zircon by conventional leaching of oxalic acid. 2. An improved process as claimed in claims 1 wherein the treatment is effected under agitation or stationary condition. 3. An improved process for the removal of iron from zircon substantially as herein described with reference to the examples. |
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1516-del-1994-correspondence-others.pdf
1516-del-1994-description (complete).pdf
Patent Number | 190353 | ||||||||||||||||||||||||||||||||||||||||||||||||
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Indian Patent Application Number | 1516/DEL/1994 | ||||||||||||||||||||||||||||||||||||||||||||||||
PG Journal Number | 31/2009 | ||||||||||||||||||||||||||||||||||||||||||||||||
Publication Date | 31-Jul-2009 | ||||||||||||||||||||||||||||||||||||||||||||||||
Grant Date | 24-Feb-2004 | ||||||||||||||||||||||||||||||||||||||||||||||||
Date of Filing | 24-Nov-1994 | ||||||||||||||||||||||||||||||||||||||||||||||||
Name of Patentee | COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH | ||||||||||||||||||||||||||||||||||||||||||||||||
Applicant Address | RAFI MARG, NEW DELHI-110001, INDIA. | ||||||||||||||||||||||||||||||||||||||||||||||||
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PCT International Classification Number | C21B 15/00 | ||||||||||||||||||||||||||||||||||||||||||||||||
PCT International Application Number | N/A | ||||||||||||||||||||||||||||||||||||||||||||||||
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