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

Hello Ravi,

To answer your questions;-

1. Dear Sir We adopting the Method for Determination of SiO2 as follow :
 0.5 gm of sample + 0.5 gm NH4Cl Mix Vigourly till smell of NH3 comes then kept for 30 - 40 Min of Slow Hot Plate (70 Deg. Celsius) then Filter thorugh Whatmann Filter Paper42 . My Question is "what is the purpose of NH4Cl addition in this Analysis"

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.

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?

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.

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

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 oxate 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.Is any Rapid MgO Method for Mgo Determination.

MgO can be analysed by EDTA titration of the filtrate from the "Rapid CaO" test above. Since all of the CaO is filtered out as insoluvle calcium oxalate, the MgO remains in the filtrate and can be titrated directly with EDTA. See;- http://www.ncbi.nlm.nih.gov/pubmed/18965740

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

Please clarify... what is TC & MC?

8.In LSF formula from which calculation of we get 2.8 part of SiO2 ,1.2 part of Fe2O3 & 0.65 part of AL2O3 & also 0.7 SO3.

Actually it's the other way around;- 1.18 * Al2O3 and 0.65 * Fe2O3. These factors are derived from the phase equilibria of the CaO-SiO2-Al2O3-Fe2O3 system at the point where free CaO first starts to form. ie where LSF =1.  A discussion on this subject can be found here;-  http://www.cemnet.com/Forum/thread/108168/lsf-formula.html

http://books.google.com.au/books?id=1BOETtwi7mMC&pg=PA56&lpg=PA56&dq=derivation+of+LSF+formula&source=bl&ots=6XxcMA1VxB&sig=ZGdFf-EOuYpQVneAxDrTC7bKB8E&hl=en&sa=X&ei=oqhsUf-2K--TiAey3oCQBQ&ved=0CE0Q6AEwBA#v=onepage&q=derivation%20of%20LSF%20formula&f=false

The 0.7 SO3 applies only to the application of the LSF formula to cement, to allow for the CaO combined with SO3 in gypsum. ie (CaO=56, SO3=80, 56/80 =0.7)

9.How to do more than 5 component Raw Mix design.Please provide me Calculus or Suggest in excel.

This is a very complex and time consuming undertaking. So, unless somebody has already written such a raw mix design program, you will have to work it out for yourself using simultaneous equations,... methods for this can be found on the internet. eg; http://www.idomaths.com/simeq.php

Regards.

Ted.

Yet Another Raw Mix Design program can be found on this forum:

http://www.cemnet.com/Forum/thread/149516?page=2

Hello Ravi,

I have researched and found enough information to attempt an more detailed explanation on your question #8;-

8.In LSF formula from which calculation of we get 2.8 part of SiO2 ,1.2 part of Fe2O3 & 0.65 part of AL2O3 & also 0.7 SO3.

Very simply speaking, LSF is the theoretical point in the C-S-A-F system where there is just enough CaO present to react completely to form C3S from C2S  at 1450oC under equilibrium conditions.

At this point the C₂S content of the clinker would theoretically be = 0. Therefore you would only expect C₃S, C₃A and C₄AF to exist at this point on the C-S-A-F quaternary phase diagram. While this is certainly true for C₃S and C₄AF, it turns out that a significant amount of SiO2 is incorporated into the C3A at this point and its actual composition is closer to C_3.31AS_0.39

Therefore, assuming that the minerals existing at the point of lime saturation are C₃S, C₄AF and C_3.31AS_0.39  we can the say that the sum of the oxides, SiO₂, Fe₂O₃ and Al₂O₃ in these minerals, expressed as a molar fraction of the CaO, will be equal to unity.

Now, given that the minerals existing at the point of lime saturation are C₃S, C₄AF and C_3.31AS_0.39 we can calculate the molar weight ratios of SiO₂/CaO, Fe₂O₃/CaO and Al₂O₃/CaO in these minerals. Below is the worked example for Al₂O₃and Fe₂O₃ in C₄AF;-

Al₂O₃ / CaO    =  102/(4*56) = 102/224 = 0.455

Fe₂O₃ / CaO   =  159.7/(4*56) = 159.7/224 = 0.713

Using the same method we can calculate the molar weight ratios for all of the minerals present. These are shown in the table below;-

Mineral -->                C₃S             C₄AF            C_3.31AS_0.39 

SiO₂ / CaO               0.357               0                    0.126

Al₂O₃ / CaO                0                0.455                 0.549

Fe₂O₃ / CaO               0                0.714                     0

Let the relative multipliers for SiO₂, Al₂O₃ and Fe₂O₃ required for lime saturation be x, y and z respectively.  Now, using the molar weight ratio information in the table above, we can write three equations (one for each mineral) which are all true at the lime saturation point;-

The three equations take the form;-

x * SiO₂/CaO +  y * Al₂O₃/CaO + z* Fe₂O₃/CaO =   1

and are;-

For C₃S;-                x *  0.357  +  y * 0  +  z * 0 = 1                   (Eq.1)

For C₄AF;-              x *  0  + y * 0.455 + z * 0.714 = 1                (Eq.2)

For C_3.31AS_0.39;-     x *  0.126  + y * 0.549 + z * 0 = 1                (Eq.3)

Solving Eq.1 we have;-

 x *  0.357 + y * 0 + z * 0 = 1 

x *  0.357  = 1 

x  =  1 / 0.357

x  = 2.8            (Which is the LSF coefficient for SiO₂)

Simplifying Eq.2 and Eq.3 we get;-

y * 0.455 + z * 0.714 = 1                                               (Eq.3)         

and

x *  0.126  + y * 0.549  = 1                                            (Eq.4)          

Substituting for x in Eq.4 we have;-

2.8 *  0.126  + y * 0.549  = 1    

0.353 + y * 0.549  = 1 

y = (1 - 0.353) / 0.549

y = 1.18              (Which is the LSF coefficient for Al₂O₃)

Now, substituting for y in Eq.3 we get;-

1.18 * 0.455 + z * 0.714 = 1  

0.537 +  z * 0.714 = 1  

z = (1 - 0.537) / 0.714

z = 0.65           (Which is the LSF coefficient for Fe₂O₃) 

This means that;-

2.8 * SiO2/CaO + 1.18 * Al₂O₃/CaO + 0.65 * Fe₂O₃ /CaO =  1

or;-

2.8 * SiO2 + 1.18 * Al₂O₃ + 0.65 * Fe₂O₃ =  CaO

or;-

                         CaO

______________________________        =  1            (ie. The lime saturation factor)

2.8 * SiO2 + 1.18 * Al₂O₃ + 0.65 *  Fe₂O₃

Regards,

Ted.