8. Environmental impact

Hydrometallurgical processes have an environmental impact on water. We have to take this into account. Moreover, hydrometallurgical plants are considered to be classified facilities, and their discharges are therefore subject to authorization and regular monitoring.

Since hydrometallurgy generally involves the use of acidic or basic solutions, discharges linked to purging or washing are inevitably necessary. A water treatment plant is mandatory to eliminate metals in solution before discharge into the natural environment. As effluent neutralization is inevitably necessary, there will be significant discharge of salts in the form of chlorides and sulfates. However, numerous water treatment techniques have been developed, and “near-zero” discharges are sometimes achieved.

The volume of waste generated can also be considerable. Because it contains...