Table 2.

Experimental results at different times for the precipitation of As-S mineral treatments at different pH (6.1, 6.45 and 7.1)

Experiment	texp (d)	pHt	[TotAs]t (mM)	[SO42−]t (mM)	[H2S]t (mM)	Sloss/ASloss‡
pH = 6.1	0	6.17	0.55±0.01	0.81±0.03	0.00±0.00	--
	6	5.93	0.05±0.02	0.12±0.01	0.01±0.00	1.34
	9	5.97	0.00±0.00	0.07±0.01	0.02±0.01	1.32
	12	5.90	0.00±0.00	0.09±0.01	0.03±0.01	1.25
	35	5.96	0.00±0.00	0.05±0.00	0.05±0.00	1.29
pH = 6.45	0	6.44	0.51±0.00	0.78±0.02	0.00±0.00	--
	6	6.49	0.25±0.03	0.35±0.02	0.05±0.01	1.47
	9	6.49	0.10±0.00	0.20±0.02	0.04±0.01	1.31
	12	6.47	0.07±0.02	0.17±0.04	0.04±0.01	1.31
	34	6.49	0.03±0.00	0.14±0.01	0.03±0.00	1.27
pH = 7.1	0	7.13	0.51±0.01	1.09±0.05	0.00±0.00	--
	6	7.15	0.39±0.01	0.87±0.05	0.08±0.01	1.27
	9	7.15	0.27±0.03	0.57±0.01	0.11±0.00	1.80
	12	7.19	0.24±0.00	0.38±0.03	0.26±0.02	1.72
	33	7.15	0.12±0.00	0.38±0.00	0.25±0.04	1.19

^‡S and As losses are defined as the difference between the total initial concentration and the concentration at time t:

S_loss = (SO₄²⁻ + H₂S)₀ − (SO₄²⁻ + H₂S)_t

As_loss = (TotAs)₀ − (TotAs)_t