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I got 22 lbs but I think it's wrong, here's the question:

The process for the production of titanium dioxide (TiO2) used by Canadian Titanium Pigments at Varennis, Quebec. Sorel slag of the following analysis is fed to a digester and reacted with H2SO4, which enters as 67 wt% H2SO4 in a water solution.
TiO4: 70 wt%
Fe: 8 wt%
Inert Silicates: 22 wt%

The reactions in the digester are as follows:
TiO2 + H2SO4 -> TiOSO4 + H2O
H2SO4 _ Fe + 0.5 O2 -> FeSO4 + H2O

Both reactions are complete The theoretically required amount of H2SO4 for the Sorel slag is fed. Pure oxygen is fed in the theoretical amount for all the Fe in the Sorel slag. Scrap iron (Fe) is added to the digester to reduce the formation of the ferric sulfate to negligible amounts. Thirty six pounds of scrap iron are added per pound of Sorel slag.

The products of the digester are sent to the clarifier, where all the inert silicates and unreacted Fe are removed, The solution of TiOSO4 and FeSO4 from the clarifier is cooled, crystallizing the FeSO4 which is completely removed by a filter. The product TiOSO4 solution from the filter is evaporated down to a slurry that is 82% by weight TiOSO4.

The Slurry is sent to a dryer from which a product of pure hydrate, TiOSO4 *H2O is obtained. The hydrate crystals are sent to a direct fired rotary kiln, where the pure TiO2 is produced according to the following reaction.

TiOSO4*H2O -> TiO2 + H2SO4

The reaction goes to completion

On the basis of 100 lb of Sorel flag feed, calculate:

A) The pounds of water removed by the evaporator:
B) The exit lb of H2O per lb dry air from the dryer if the air enters having 0.036 moles H2O
per mole dry air and the rate is 18 lbmol of dry air per 100lb of Sorel slag entering the digester
C) The pounds of product TiO2

[Art Montemayor]

Alex:

If this is a serious query on how to solve a Ch. E. problem, then show us your work. To be specific, show us your algorithm (or solution scheme), your calculation (in spreadsheet format - preferably Excel), complete with equations & references.

All that you have submitted is a copy of your homework problem. The least you could do is to show us all of your work in resolving this problem - specifically showing the steps and calculations you made to arrive at the 22 lbs (of what? you don't tell us if it is the answer to A), B), or C))