| Insoluble
matter: |
10
gms sample dissolved in a mixture
of 100 ml water and 7 ml sulfuric acid
heated on a steam bath for 1 hr. Filter
the solution through tared S.G.crucible
& wash with hot water till acid
free
Dry it at 105 C. Cool & Weigh.NMT
0.02%
w/w insoluble matter. |
| Chlorides
: |
NMT
0.002% when tested with 1 gm sample
dissolved in 10 ml water and 3 ml. HNO3
shows w/w. not more chlorides than that
produced with 0.03 ml of 0.02N Hcl. |
| Sulphate
: |
Dissolved
10 gm in a mixture of 75 ml
water and 10 ml Hcl & filter. Neutra-
the std. lise filterate with NH4OH,
dilute with
water to 100 ml & mix To 10 ml of
this
solution added 1 ml of 0.6 NHCL &
1 ml
BaCl2 TS mixed & allow it to stand
for
10 min. Turbidity produced should not
be more than that produced with 0.10
ml of 0.02 N H2SO4 and 1 ml BaCl2 T.S.
i.e. NMT 0.01 % `SO4'
|
| Iron
: |
NMT
0.002% using 1.0 gm in 20 ml
water and 3 ml HCL |
| Lead(`as
pb') : |
NMT
5 ppm determind by
spectrometrically |
Substances
not ppt.tested by
Ammonium sulphate : |
NMT
0.4% w/w |
| Assay
as ZnO' : |
NLT
70% of ZnO
NLT 56.0 % |
