Above: A diagram of an autoclave
Below: A picture of an autoclave

(photograph from Dynatec Corporation)

Autoclaves are pressure vessels in the form of cylinders (horizontal or vertical) or long horizontal tubes. To ensure complete mixing of reagents, autoclaves are usually agitated. Methods of agitation vary; and include the injection of high-pressure steam, mechanical agitation, or rotation of the whole autoclave. When used with corrosive media, autoclaves are constructed of special steel alloys, titanium, and other high-grade materials. In some instances the interior surfaces of the autoclaves are lined with rubber or ceramic material.

Autoclaves are extensively utilised by Dynatec for non-ferrous hydrometallurgy. Autoclaves are used in the Acid Matte Leach Process and the Nickel Laterite Acid Leach Process, because they allow high temperatures and pressures to be used. The autoclaves contain four to six compartments, each agitated with an electrically-driven turbine mixer from the top. The autoclaves are equipped with agitators to keep the fine solids in suspension and promote the best leaching action.

The schematic below shows the components of a horizontal acid leach autoclave:

  1. Motor Drive Assembly for Agitator
  2. Compartment Divider
  3. Agitator Shaft
  4. Service Nozzles
  5. Support Saddle
  6. Carbon Steel Shell/Lead and Brick Lined

Schematic of a Horizontal Acid Leach Autoclave