Table 5.

Extraction of gold from gold ore by conventional systems.

System	pH	Leaching yield	reference
0.05 M NBS	8	86.24% (25 °C, 20h)	In this paper
4 kg/t NaCN	11	71.32% (25 °C, 20h)	From production line
0.13 M thiourea, 0.09 M Fe2(SO4)3	1.25	78.35% (25 °C, 20h)	[40]
0.5 M Na2S2O3, 0.2 M CuSO4, 1 M NH3	9.5	80.16% (25 °C, 20h)	[40]
20 g/L KI, 4 g/L I2	8.2	88.67% (25 °C, 20h)	[7]