4 replies to this topic

[rectification24]

Hey,

 

can someone please help me? I have one problem that I have to solve, but unfortunately I don't know if my result is correct.

Could someone please look at my work and tell me if I did any mistake? 

I would be very grateful for any help.

 

Regards,

Filip

 

Description of my problem could be seen here and solution down under:

 

Roasted copper ore containing the copper as CuSO4 is to be extracted in a counter-current 

stage extractor. Charge consists of 10 tons of inert solids, 2 tons of 

copper sulfate (CuSO₄), and 0.5 ton of water. The strong solution produced is to 

consist of 90% H2O and 10% CuSO4 by weight. The recovery of CuSO4 is to be 98% of 

that in the ore. Pure water is to be used as the fresh solvent. After each stage, 1 ton of 

inert solids retains 2 tons of water plus the copper sulfate dissolved in that water. 

Equilibrium is attained in each stage. How many stages are required? 

 

 

2 t CuSO₄....................100%                                                       1.96t....................10%

      x       ......................98%                                                             x........................90%

                                         

x=1.96 t CuSO₄                                                                                                                     x=17.64 t H₂O

 

extract:   1.96 t CuSO₄/17.64 t H₂O = 1.12 t CuSO₄/10 t H₂O

 

raffinate:

 

0.04 t CuSO₄/10 t inert solid

 

As base we define 10 t of inert solid (without H2O and CuSO₄)

 

CuSO₄ in: 2 t 

 

CuSO₄ out:

 

0.04 +(1.12 /(1.12 +10) *(S-20+0.5)) = 0.101*S - 1.924

 

 

CuSO₄ in = CuSO₄ out

 

2 = 0.101*S - 1.924

 

S = 38.85 t H₂O  (amount of solvent)

 

 

y_a = ((20*1.12/(1.12+10)) + (1.12/(1.12+10)*(38.85-20+0.5)) - 2 ) / 38.85

y_{a =} 0.0505

 

y_b = 0

 

y_a^* = 1.12/(1.12+10) = 0.101

 

y_b^{* =} 0.04/20 = 0.002

 

Number of stages:

 

N=log(y_b - y_b^*/(y_a-y_a^*)) / log(y_b-y_a/(y_b^*- y_a^*))

 

N=4.8=5

 

 

 

 

 

 

              

[breizh]

Hi ,

My calculation , different from yours !  

Breizh

 

 

 

Ya 0.1 Yb 0 Xa =Ya* 0.16 Xb=Yb* 0.001332     N 8.248054

Edited by breizh, 08 August 2014 - 03:24 AM.

[rectification24]

Could you please send me your calculations that I will be able to see what I did wrong?

 

Filip

 

 

 

Hi ,

My calculation , different from yours !  

Breizh

 

 

 

Ya 0.1 Yb 0 Xa =Ya* 0.16 Xb=Yb* 0.001332     N 8.248054

 

[breizh]

Hi ,

 

Consider my excel sheet ! Nothing granted.

 

Breizh

[rectification24]

Thanks a lot.

 

Filip

 

Hi ,

 

Consider my excel sheet ! Nothing granted.

 

Breizh