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

Table 1

Experimental conditions of 2⁴ full factorial design.

N.	Treat.	A; Sulphuric acid	B; Citric acid	C; Temp.	D; Pulp density	A; (M)	B; (g L^−1)	C; (∘C)	D; (g L^−1)
1	(1)	−	−	−	−	0.9	7	40	100
2	a	+	−	−	−	1.4	7	40	100
3	b	−	+	−	−	0.9	20	40	100
4	ab	+	+	−	−	1.4	20	40	100
5	c	−	−	+	−	0.9	7	80	100
6	ac	+	−	+	−	1.4	7	80	100
7	bc	−	+	+	−	0.9	20	80	100
8	abc	+	+	+	−	1.4	20	80	100
9	d	−	−	−	+	1.8	14	40	200
10	ad	+	−	−	+	2.7	14	40	200
11	bd	−	+	−	+	1.8	40	40	200
12	abd	+	+	−	+	2.7	40	40	200
13	cd	−	−	+	+	1.8	14	80	200
14	acd	+	−	+	+	2.7	14	80	200
15	bcd	−	+	+	+	1.8	40	80	200
16	abcd	+	+	+	+	2.7	40	80	200
17	0	0	0	0	0	1.7	20	60	150
18	0	0	0	0	0	1.7	20	60	150