Title of Invention | METHOD FOR ESTIMATION OF SULPHUR IN COKE SAMPLES |
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Abstract | 1. A method for the estimation of sulphur in a coke sample, comprising the steps of igniting the coke sample in a stream of oxygen to convert the sulphur in the sample to sulphur dioxide, passing the sulphur dioxide into a solution of iodine, followed by estimation of the excess iodine, and calculating the quantity of sulpur from the formula X(0.1) x standard correction where X= volume of Potassium iodate solution. |
Full Text | FIELD OF THE INVENTION: This invention relates to a method for the estimation of sulpur in coke samples. BACKGROUND OF THE INVENTION: Coke is used as fuel in blast furnace. Coke contains sulfur which is transferred to hot metal during blast furnace operation. Sulpur is present as impurity in hot metal and is not a desirable element in steel also. Sulfur has a detrimental influence on the properties of steel. For high sulfur additional fuel is required in the blast furnace and at steel melting shop extra DS compound is required to lower the level of sulfur. Hence it is very important to ascertain the sulfur content in coke, for blast furnace operation. According to existing methods, the coke sample is ground to pass a 72 mesh sieve, and is heated with eschka mixture which is a 2:1 mixture of magnesium oxide and anhydrous sodium carbonate. The reaction is conducted in an oxidizing atmosphere at 800°C to convert all sulpur into sulphate, which is extracted and determined gravimetrically. In this method, an accurately weighed quantity of sample is transferred to a porcelain crucible and mixed with eschka mixture. It is levelled and covered with a further quantity of reagent, and the crucible is kept for four hours in a muffle furnace at 800°C. The cake formed in crucible is extracted, acidified and boiled to expel carbon dioxide and filtered through a paid which is washed with water. The acidity of the solution is maintained at (3-4%). The solution is boiled and precipitated out as barium sulphate by adding barium chloride. The precipitate is filtered washed with water, ignited in a pre weighed silica crucible, at 800°C for 1 hours, cooled and weighed. A blank is run simultaneously, to allow for any atmospheric contamination, and sulphur is calculated from the corrected weight of barium Sulphate. This is a process involving a number of steps of heating, extraction, filtration, acedification etc. rendering the process time consuming and cumbersome. Therefore, the need exists in the industry to develop a process which is easy to run, quick and cost-effective. OBEJCTS OF THE INVENTION: It is therefore an object of this invention to propose a process for estimation of sulphur in coke samples which is quick and simple. It is a further object of this invention to propose a process for estimation of sulphur in coke samples which uses simple, easily available reagents and is cost-effective. These and other object of the invention will be apparent from the ensuing description. At the outset of the description, which follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment and the teachings of the invention is not intended to be taken restrictively. BREIF DESCRIPTION OF THE INVENTION: Thus according to this invention is provided a method for the estimation of sulphur in coke samples. In accordance with this invention the coke sample is ignited in a stream of oxygen, whereby the sulphur in the sample of coke is converted into sulphur dioxide which is bubbled into a solution of iodine liberated from the reaction of potassium iodate and potassium iodide in acidic medium. The excess of iodine is back titrated with std. sodium thio-sulphate solution. A solution of concentrated hydrochloric acid, potassium iodide and standard potassium iodate solution are taken in an absorption vessel alongwith a few drops of starch solution, as indicator. A quantity of the dried sample is placed in a combustion boat. A small piece of tin-foil is placed below the sample. The boat is carefully inserted into the hot zone (Temperature 1150-1200°C) of the combustion tube of furnace. The same is preheated for one minute and then oxygen (free from SO2) is passed at high speed of 1.5 to 2.0 L/minute. Gas is bubbled through the iodine solution. The colour of solution gradually disappears and tends to become colourless. At this time some more standard potassium iodate solution is added so that the colour of the solution persists. The flow of oxygen is further continued for 30 seconds to ensure that there is no further change in the colour. If the std. potassium iodate solution is added in excess, then the excess of iodine is back titrated with std. Na-thio-sulphate solution. A reference sample is also analysed, and appropriate correction is applied to get the actual value of the sample. Sulphur is calculated from the formula =X(0.1) x Std. correction Where X= Volume of std. KIO3 solution. The invention will now be explained in greater detail with the help of the following non-limiting example. Example: Reagents: Conc. HC1, Potassium iodide (2.5%), (N/32) Std. Potassium iodate solution, (N/32) Std. Na-thio-sulphate and (1%) Starch solution. A furnace unit is fitted with a combustion tube and the coke sample is ignited in a stream of oxygen at 1200°C. 10 ml. Conc. HC1, 8 ml . (2.5%) KI solution 3-4 ml. std. KI03 solution are taken in the absorption vessel. The volume is made 100 ml. with chilled distilled water. A few drops of freshly prepared starch solution is also added as indicator. 0.5 gm of the dried sample is place in a combustion boat and a small piece of tin-foil is placed below the sample. The boat is carefully inserted into a hot zone of the combustion tube of furnace. The sample is preheated for one minute and then oxygen (free from SO2) is passed at a speed of 2L/min and the sample is ignited at 1200°C. Gas is bubbled through the iodine solution. As the colour of solution gradually disappears more standard potassium iodate solution is added from the burette so that the colour of the solution persists. The flow of oxygen is further continued for 30 seconds to ensure that there is no more change in the colour. The excess is back titrated using std. sodium thiosulphate solution. In order to validate the method samples has been analysed by both the methods and the results are given below. However, the method according to the present invention is far more efficient, quick and cost effective compared to the methods existing in the prior art. WE CLAIM; 1. A method for the estimation of sulphur in a coke sample, comprising the steps of igniting the coke sample in a stream of oxygen to convert the sulphur in the sample to sulphur dioxide, passing the sulphur dioxide into a solution of iodine, followed by estimation of the excess iodine, and calculating the quantity of sulpur from the formula X(0.1) x standard correction where X= volume of Potassium iodate solution. 2. The method as claimed in claim 1, wherein the coke sample is ignited at a temperature in the range of 1150 to 1200°C. 3. The method as claimed in claim 1 wherein the iodine solution is prepared using concentrate hydrochloric acid, potassium iodide (KI) and standard potassium iodate (KI03) solution in predetermined quantities. 4. The method as claimed in claim 1, wherein the iodine solution includes an indicator such as starch. 5. The method as claimed in claim 1, wherein a small tin-foil is kept below the coke sample during ignition. 6. The method as claimed in claim 1, wherein the stream of oxygen is passed into the sample at a speed of 1.5 to 2 litres /minute. 7. The method as claimed in claim 1, wherein excess of potassium iodate is added to the KI-KIO3 solution while sulphur dioxide is passed into it, so that the colour of iodine persists. 8. The method as claimed in the preceding claims, wherein the flow of oxygen containing sulphur dioxide, is continued upto a time where no more change in iodine colour is observed. 9. The method as claimed in claim 1, wherein the excess iodine is estimated by back-titrating with a standard sodium thiosulphate solution. 10. The method as claimed in claim 1, wherein the standard correction is introduced by analyzing a reference sample. 1. A method for the estimation of sulphur in a coke sample, comprising the steps of igniting the coke sample in a stream of oxygen to convert the sulphur in the sample to sulphur dioxide, passing the sulphur dioxide into a solution of iodine, followed by estimation of the excess iodine, and calculating the quantity of sulpur from the formula X(0.1) x standard correction where X= volume of Potassium iodate solution. |
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01266-kol-2007-correspondence others.pdf
01266-kol-2007-description provisional.pdf
1266 kol 2007 search report[1].pdf
1266-KOL-2007-(09-11-2012)-CORRESPONDENCE.pdf
1266-KOL-2007-(27-06-2012)-AMANDED CLAIMS.pdf
1266-KOL-2007-(27-06-2012)-DESCRIPTION (COMPLETE).pdf
1266-KOL-2007-(27-06-2012)-EXAMINATION REPORT REPLY RECEIVED.pdf
1266-KOL-2007-(27-06-2012)-FORM-1-1.pdf
1266-KOL-2007-(27-06-2012)-FORM-1.pdf
1266-KOL-2007-(27-06-2012)-FORM-2.pdf
1266-KOL-2007-(27-06-2012)-PETITION UNDER RULE 137.pdf
1266-KOL-2007-CORRESPONDENCE 1.1.pdf
1266-KOL-2007-CORRESPONDENCE 1.2.pdf
1266-kol-2007-correspondence.pdf
1266-kol-2007-description (complete).pdf
1266-KOL-2007-EXAMINATION REPORT.pdf
1266-KOL-2007-GRANTED-CLAIMS.pdf
1266-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf
1266-KOL-2007-GRANTED-FORM 1.pdf
1266-KOL-2007-GRANTED-FORM 2.pdf
1266-KOL-2007-GRANTED-SPECIFICATION.pdf
1266-KOL-2007-REPLY TO EXAMINATION REPORT.pdf
1266-kol-2007-specification.pdf
Patent Number | 255462 | |||||||||
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Indian Patent Application Number | 1266/KOL/2007 | |||||||||
PG Journal Number | 09/2013 | |||||||||
Publication Date | 01-Mar-2013 | |||||||||
Grant Date | 25-Feb-2013 | |||||||||
Date of Filing | 07-Sep-2007 | |||||||||
Name of Patentee | TATA STEEL LIMITED | |||||||||
Applicant Address | JAMSHEDPUR 831001 | |||||||||
Inventors:
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PCT International Classification Number | C10B57/00 | |||||||||
PCT International Application Number | N/A | |||||||||
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PCT Conventions:
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