A representative sample of heavy oil evaporator blowdown wastewater (“EBD”) wastewater, containing anomalous levels of lithium grading 87 mg/L, was transported from the Alberta oil fields to PurLucid’s laboratory facilities in Edmonton for testing.
The pre-treatment step to create brine feedstock free of physical particulate resulted in an 18% loss of lithium, however the step removed nearly all hydrocarbons, silica and other solids. The primary processing of the brine included treatment to recover sodium chloride (NaCl), which represents a potentially saleable commercial product, and resulted in a minor 1% loss of lithium. An additional 16% of lithium was lost during the sulfur removal and magnesium oxide recovery step. After crystallization of the lithium carbonate 21% of lithium remained in the final brine. This portion represents a high probability of additional recovery through current optimization of the process. The final concentrate included 34.8 mg/L lithium, representing a 40% recovery rate, along with other potentially commercially-viable minerals including boron and vanadium.
Overall, the treatment process removed all suspended solids, including 99.7% of hydrocarbons and 99.9% of silica and other scale-forming minerals. Thus, upon process completion remaining water was suitable for reuse in stream generation.
Further optimization testing is currently underway using oil well wastewater versus oil sands wastewater. This may reduce loss during the initial filtration step due to the lower concentration of hydrocarbons and other impurities. Oil sands wastewater offers the advantage of significant environmental revenue for the treatment of this heavy oil wastewater, which has the potential to more than offset front end recovery losses, therefore both markets are being actively pursued. Primary areas of optimization involve reducing potential capital and operating costs in the handling of large volumes of wastewater and maximizing the positive economic impact of by-products including sodium chloride and calcium chloride.
The primary goal is to reduce overall physical plant components that minimize potential operating and capital costs optimized to high volume mid-grade lithium brine of Alberta. To date work has been successful and initial optimization results are expected shortly along with independent work being carried out by the Saskatchewan Research Council.
Heavy oil evaporator blowdown wastewater (“EBD”) is one of the byproducts of steam assisted gravity drainage ("SAGD") during production of heavy oil. EBD was specifically targeted as the wastewater contains mid-level concentrations of lithium and has the potential to generate high environmental revenue based on current disposal costs.
Below: Lithium carbonate produced from Sturgeon Lake Oilfield production water using MGX's patent pending recovery process and PurLucid's patented oilfield wastewater filtration technologies.