chari
80 posts
TimePosted 20/04/2013 09:31:48
chari says

re Traditional Analysis by Gravimteric & Volumetric Analysis of Cement or Clinker for Determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO

Dear Ted,

Nicely expalined the details.

Regards

vdchari

 

 

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Ravi Chauhan
7 posts
TimePosted 06/03/2014 21:43:41

re Traditional Analysis by Gravimteric & Volumetric Analysis of Cement or Clinker for Determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO

Hello Sir,

Reply on :Could you please clarify the method. At what stage is water added in the example above? Normally hydrochloric acid is used to dissolve the clinker minerals and gypsum in the determination of free silica (insoluble residue) in clinker or cement, not ammonium chloride.

Method : Dear Sir We adopting the Method for Determination of SiO2 as follow  1) In 150 ml Beaker take 0.5 gm of Clinker Sample + 0.5 gm NH4Cl then crushed Vigourly with Glass Rod till smell of NH3 comes . 2)Then add 5 ml Conc HCL & kept for kept for 30 - 40 Min of Slow Hot Plate70 °[Gel Like Material Form] in mean crushed & mix with glass rod to avoid any particle unreated with HCl. 3)Then add 50-60 ml Distilled Water ,Warm & Filter Through Whatmann Filter Paper40.Ignite the Filter Paper give Silica.

Please specify chemical reaction in it.

2. Further in R2O3 Determination what will happened if We added more 1:6 NH4OH on Analysis after formation of Precipitate of R2O3 & Also why HNO3 is added , R2O3 Pricipitate get form without adding it.

R2O3 is composed of Al2O3 + Fe2O3.  Al2O3 is amphoteric (ie it will dissolve in an excess of either acid or base.)  NH4OH is strongly basic. So, if you added too much NH4OH, it would dissolve some of the Al2O3 out of the R2O3 precipitate giving you a low result for Al2O3.

Please clarify at what point in the test HNO3 is used?

Take Filtrate in the above mention method for Silica Determination,Kept on Hot Plate  for Just Boil then add 2-3 Drops of HNO3 followed by Methyl red indicator till Red color comes then 1.6 NH4OH added till Yellow color Appear,kept on slow hot plate for 30 min then Filter through WM FP 41 then washed with hot 2% Nh4No3 & then with water,.Ignite the Filter Paper give R2O3

 Please specify chemical reaction in it. & R stand for Reduced state or anything else.

3.Can You provide Chemical Reaction involved in Gravimteric Analysis of Cement or Clinker for the determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO.

There are many reactions involved in each analysis, please be more specific.

Take filtrate of R2O3 and keep on hot plate to boil, then add 25 ml ammonium oxalate with constant stirring up to complete calcium oxalate precipitate. Keep for few minute on hot plate and filter through W.No.40. Wash the precipitate with hot distilled water till oxalate remove. Take the precipitate in beaker and dissolve in 50% hot Sulphuric Acid (H2SO4), then heat to the solution to 70-80OC and titrate against Std. KMnO4. Note down the consumption of KMnO4.

The filtrate of CaO is cooled in ice and magnesium is precipitated as Magnesium Ammonium Phosphate by adding 25% solution of di-ammonium hydrogen orthophosphate with constant stirring. The solution is made to alkaline by adding Ammonia drop by drop and then little excess. The precipitate is allowed to settle for 24 hrs, then filter through W.No.42, washed with washing agent (1:20) one part of ammonia & 20 parts of distilled water by volume and then with distilled water till free from chloride. Ignite the
precipitated, cool and weigh

Please specify chemical reaction in above Methods & Role of Various Chemical used in it.

 4.Can You provide Chemical Reaction involved in Gravimteric & Volumetric  Analysis of Cement or Clinker by Rapid Cao Method :
0.5 gm sample + 5-10 ml Conc HCL then Boil & add methyl red after that 1:6 NH4OH till Yellow Color appear then Oxalic acid added then 7% Ammonium Oxalate added & kept for digestion for 30-40 Min on Slow Hot Plate ,Filter thorugh 41 WFP & 10-20 ml H2SO4 & Titrate against KMnO4 in Hot Condition

Please specify chemical reaction in above Methods & Role of Various Chemical used in it.                    

5.Role of Oxalic Acid in Rapid CaO Method & Also Give Chemical Reaction involved in it

Oxalic acid is added to the dissolved cement or clinker to precipitate insoluble calcium oxalate from calcium chloride by the following equation;-

CaCl2 + (COOH)2  ----> Ca(COO)2 + 2HCl

Ammonium oxalate is added as a buffer to keep the calcium oxalate from redissolving in the digestion stage. The Calcium oxalate precipitate is filtered and redissolved in sulphuric acid and the oxalic acid which is formed is titrated with potassium permanganate. This titration is an oxidation/reduction reaction in which the intense red colour of the permanganate itself is used as the indicator eg;-

Calcium oxalate dissolves in sulphuric acid;-

Ca(COO)2  + H2SO4  ------> (COOH)2 + CaSO4           

Permanganate oxidises oxalic acid to CO2 and H2O while itself being reduced into potassium and manganese sulphates;-

5 (COOH)2 + 2 KMnO4 + 3 H2SO4 ------> K2SO4 + 2 MnSO4 + 8 H2O +  10 CO2

 6.Give Chemical Reaction involved in TC & MC & also Method.Theoretical Calculus is also needed

Please clarify... what is TC & MC?

Total Carbonates & Magnesium Carbonates

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Ted Krapkat
537 posts
TimePosted 10/03/2014 05:53:11

re Traditional Analysis by Gravimteric & Volumetric Analysis of Cement or Clinker for Determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO

Hello Ravi,

1. Reply on: Could you please clarify the method. At what stage is water added in the example above? Normally hydrochloric acid is used to dissolve the clinker minerals and gypsum in the determination of free silica (insoluble residue) in clinker or cement, not ammonium chloride.

Method : Dear Sir We adopting the Method for Determination of SiO2 as follow 1) In 150 ml Beaker take 0.5 gm of Clinker Sample + 0.5 gm NH4Cl then crushed Vigourly with Glass Rod till smell of NH3 comes . 2)Then add 5 ml Conc HCL & kept for kept for 30 - 40 Min of Slow Hot Plate70 °[Gel Like Material Form] in mean crushed & mix with glass rod to avoid any particle unreacted with HCl. 3)Then add 50-60 ml Distilled Water ,Warm & Filter Through Whatmann Filter Paper40.Ignite the Filter Paper give Silica.

Please specify chemical reaction in it.

When used in this way, the NH4Cl acts to slow down the rate of the reaction of concentrated HCl with the cement, in two ways;-

(a). By physically separating the cement particles (ie by solid dilution)

(b) By acting as a mild acid and reacting with the clinker minerals (ie NH4+  ->  H+  +  NH3)

 

 

2. Further in R2O3 Determination what will happened if We added more 1:6 NH4OH on Analysis after formation of Precipitate of R2O3 & Also why HNO3 is added , R2O3 Pricipitate get form without adding it.

R2O3 is composed of Al2O3 + Fe2O3. Al2O3 is amphoteric (ie it will dissolve in an excess of either acid or base.) NH4OH is strongly basic. So, if you added too much NH4OH, it would dissolve some of the Al2O3 out of the R2O3 precipitate giving you a low result for Al2O3.

Take Filtrate in the above mention method for Silica Determination, Kept on Hot Plate for Just Boil then add 2-3 Drops of HNO3 followed by Methyl red indicator till Red color comes then 1.6 NH4OH added till Yellow color Appear, kept on slow hot plate for 30 min then Filter through WM FP 41 then washed with hot 2% Nh4No3 & then with water,. Ignite the Filter Paper give R2O3

Please specify chemical reaction in it. & R stand for Reduced state or anything else.

There does not appear to be any need for 2-3 drops of HNO3 at this stage in the method, since the solution from the insoluble residue method is already very acidic due to the addition of conc. HCl.

R2O3 is simply a convenient way of expressing the mixture of Fe2O3 and Al2O3 which precipitate together. In this case the R represents (Al and/or Fe)  ie %R2O3 = (%Fe2O3 + %Al2O3)

 

3. Can You provide Chemical Reaction involved in Gravimteric Analysis of Cement or Clinker for the determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO.

The filtrate of CaO is cooled in ice and magnesium is precipitated as Magnesium Ammonium Phosphate by adding 25% solution of di-ammonium hydrogen orthophosphate with constant stirring. The solution is made to alkaline by adding Ammonia drop by drop and then little excess. The precipitate is allowed to settle for 24 hrs, then filter through W.No.42, washed with washing agent (1:20) one part of ammonia & 20 parts of distilled water by volume and then with distilled water till free from chloride. Ignite the
precipitated, cool and weigh

Please specify chemical reaction in above Methods & Role of Various Chemical used in it.

At the correct pH magnesium can be separated from calcium by precipitation as Magnesium Ammonium Phosphate by the reaction;=

Mg+2 + HPO4-2  -->  MgHPO4  

The pH is controlled by using ammonia. In slightly basic medium, calcium hydrogen phosphate does not precipitate and the magnesium hydrogen phosphate can be filtered off and weighed

 

 

6.Give Chemical Reaction involved in TC & MC & also Method. Theoretical Calculus is also needed

Please clarify... what is TC & MC?

Total Carbonates & Magnesium Carbonates

Please give the method you are using for Total Carbonates and Magnesium Carbonate.

 

Regards,

Ted.

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Ravi Chauhan
7 posts
TimePosted 13/03/2014 21:42:14

re Traditional Analysis by Gravimteric & Volumetric Analysis of Cement or Clinker for Determination of SiO2,Al2O3 ,Fe2O3 & Cao & MgO

Estimation of Total Carbonates {TC} – Take 0.5 g fine ground sample in a conical flask and add 25 ml 0.4 N HCl from burette. Boil the solution till complete decomposition of carbonates take place. Cool it and titrate it against 0.1N NaOH solution using phenolphthalein indicator. Note down the Burette reading. 

Estimation of Magnesium Carbonates {MgCO3 %} – Take another 10ml of 0.1N NaOH in the same conical flask (in which TC has been determined) add few drops of Thymolphthalein indicator in it and boil is slowly. If violet colour not persists than add another 10 ml of 0.1N NaOH solution in it and again boil it (Continue the same procedure till violet colour become stable during boiling) Cool it and titrate it against 0.4N HCl solution, note down the burette reading.       

Please Specify Reaction involve in it & How Theoritical Value of TC is Calculated from Raw Meal  or Kiln FeeD XRF or Chemical Analysis.

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