Hanafi
The sources give no view for it here.
التيمم على السباخ
هل يجوز التيمم على الأرض السبخة؟
Each school’s answer
In our wordsHanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
(فصل) : التيمم جائز على السباخ. خلافا لمن منعه لعموم الظاهر؛ ولأن اسم الصعيد يقع عليه كالعذب. ولأنه نوع يتطهر به فاستوى عذبه وملحه كالمائع.
«الإشراف», al-Qadi Abd al-Wahhab p. 161
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What is «in our words» is our standard wording; the books’ texts stay as they are.