Pressure oxidative leaching

Here are some frequently asked questions

• How much sample mass do I need for a bench scale pressure oxidative leach program?

  This depends on the % solids selected, typically each 1 Gal leach will require between 0.3 kg to 1.0 kg of sample (DWE) ore and the extent of the program depends on the level of study being considered. For scoping tests a matrix of approximately 3 to 9 leaches is typical.

• What does DWE stand for when talking about sample masses?

  DWE refers to dry weight equivalent (DWE) and is typically quoted as the required sample mass without any moisture takin into consideration.

• How is temperature maintained during pressure POX leaching?

  All bench scale autoclaves have controlled heating mantles and internal cooling coils to maintain accurate leach temperatures.

• How is the oxygen added and controlled during POX leaching?

  ALS have calibrated mass flow controllers on the oxygen feed lines and also measure the vent gas analysis for oxygen utilisation calculations.

• Can batch autoclaves be sampled during leaching?

  Yes, ALS can offer a suite of kinetic samples typically taken at 5, 15, 30, 60 and 90 min intervals, however the maximum number depends on pulp density and starting mass.

• Can sulphur speciations be conducted during POX leaching tests?

  Yes, ALS can offer sulphur speciation tests which are useful to control the extent of sulphur oxidation and elemental sulphur generated.

• Can I do my own testwork in ALS’s laboratory?

  Generally, no. Insurance and safety protocols typically prevent renting laboratory space and this is not part of ALS’s business model. Clients are able to visit and witness testwork but this is to observe only! Typically clients may attend on 24/7 piloting campaigns and interact with senior staff members for Technical interactions.

• Can vendors attend the ALS lab to do associated testwork?

  Yes, Vendors often attend during specific bench and pilot scale testwork periods to conduct offline tests for filtration, flocculation and thickening on fresh samples from the testwork programs. This is common during 24/7 piloting campaigns.

• Can my associates and I view the testwork at ALS’s laboratory?

  Yes, clients are always welcome to visit our facilities and observe samples or tests in progress. Inductions are required and other rules may apply to visitors.

• Will ALS dispatch my samples to third parties?

  Yes, if a testwork program is in progress, ALS will happily dispatch testwork products and feed samples to vendors, third party laboratories, and customers as required. Fees apply.

• Does ALS do bulk pilot testwork?

  Yes, piloting testwork follows a successful bench testwork program where the proposed process flowsheet has been selected. Continuous testwork will prove the viability of the selected flowsheet and confirm recycle streams and overall circuit kinetics which is not possible from only batch or bench scale tests.

• Does ALS do design engineering and consulting?

  No, as it is not our core business and would put us in direct competition with many of our clients. We can, however, put you in contact with a range of reputable engineering providers and consultants.