[Pulpper]

Hi,

I have tried to find out how to calculated Goodwin's curve. Goodwin's curve tells what is the maximum causticizing efficiency of white liquor on certain total titrable alkaline and sulfidity of liquor. If we know the TTA of liquor then we can tell what is the maximum of the white liquor causticizing efficiency. When TTA is increasing the maximum of causticizing efficiency is decreasing (see attached picture).

Can anyone tell me how the curve can be calculated?

Here some background of causticizing chemistry:
- Slaking reaction: CaO + H2O = Ca(OH)2
- Causticizing reaction: Ca(OH)2 + Na2CO3 + CaCO3 + 2NaOH

- Active alkali: AA = NaOH + Na2S
- Effective alkali: EA = NaOH + ½Na2S
- Total titrable alkali: TTA = NaOH + Na2S + Na2CO3

- Sulfidity: S = Na2S/(Na2S + NaOH) or sometimes Na2S/(Na2S + NaOH + Na2CO3)
- Causticizing Efficiency: CE = NaOH/(Na2CO3 + NaOH)

Alkali concentration of liquor are expressed in terms of the Na2O equivalent:
- 1 lb NaOH = 0.775 lb Na2O
- 1 lb Na2S = .0795 lb Na2O
- 1 lb Na2CO3 = 0.585 lb Na2O

Thanks in advance.