Pilot-scale leaching tests

In a pilot scale test using a vessel 1 m3 in volume, a solute was leached from an inert solid and the water was 75 per cent saturated in 100 s. If, in a full-scale unit, 500 kg of the inert solid containing, as before, 28 per cent by mass of the water-soluble component, is agitated with 100 m3 of water, how long will it take for all the solute to dissolve, assuming conditions are equivalent to those in the pilot scale vessel Water is saturated with the solute at a concentration of 2.5 kg/m3. 

Kylefors, K., Andreas, L. and Lagerkvist, A. (2003) A comparison of small-scale, pilot-scale and large-scale tests for predicting leaching behavior of landfilled wastes, Waste Management 23, 45-59. 

The program involved leaching selected industrial chemical process residuals with leachate derived from municipal refuse in a pilot-scale field facility measuring the concentration of the compounds which leached from the wastes and comparing these field concentrations to those in the EP and other candidate leaching tests. The Toxicity Characteristic Leaching Procedure or TCLP, is the outgrowth of these studies. 

A pilot-scale study indicated that UV oxidation was most effective at a pH of 9 and an ozone dosage of 3.3 mg/l/min. Residence times greater than 180 min coupled with high ozone doses destroyed all of the explosives, including 1,3,5-TNB. Biotoxicity tests indicated that the effluent from the UV oxidation system was toxic, due to leaching of metals from bronze impellers within the equipment. 

Chemical cleaning processes utilize alkali or acid to leach the impurities present in the coal. TRW s Gravimelt process, which has been tested on a pilot scale, utilizes molten caustic to leach mineral matter. The major drawback of a chemical cleaning process is the economics. 

Example 7.2 In a pilot scale test using a vessel Inn in volume, a solute was leached from an inert solid axid the water was 75 percent saturated in 10 seconds. 

Australian Vanadium—Uranium Ore. A calcareous camotite ore at YeeHrrie, AustraHa, is iU-suited for salt roasting and acid leaching. Dissolution of vanadium and uranium by leaching in sodium carbonate solution at elevated temperature and pressure has been tested on a pilot-plant scale... 

In Chapter 23, Nilsen et al. describe the field testing of an emulsion liquid membrane system for copper recovery from mine solutions. The small, pilot plant-scale, continuous circuit for the recovery of copper from mine waste waters and low-grade leach solutions was field tested at a copper mine. Formulation of the emulsion membranes was optimized to provide emulsions with good stability during extraction, but which could be easily broken in an electrical coalescer under mild conditions. Typical results from the tests were >90 percent copper recovery, while maintaining the membrane swelling in the range of 4-8 percent. Cost evaluations indicate the potential for cost-effective recovery of copper from such solutions. 

A continuous, mobile, pilot plant-scale LEM circuit was designed and field tested by the USBM to extract and recover copper from relatively dflute leach... 

---