Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

Table 2

Levels of factors investigated in the second series of leaching tests.

		Level
Factor		(−𝛼)	(−1)	(0)	(+1)	(+𝛼)
A	Sulphuric acid	0.5 M	1 M	1.5 M	2 M	2.5 M
B	Citric acid	0 M	0.075 M	0.15 M	0.225 M	0.3 M
C	Pulp density	10%	15%	20%	25%	30%
D	Temperature	30^∘C	40^∘C	50^∘C	60^∘C	70^∘C