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Willem P C Duyvesteyn, Julia Rose Budden, Merijn Amilcare Picavet: Extraction of bitumen from bitumen froth and biotreatment of bitumen froth tailings generated from tar sands. BHP Minerals International, Hopgood Calimafde Kalil & Judlowe, October 19, 1999: US05968349 (370 worldwide citation)

A process for the extraction of bitumen from bitumen froth generated from tar sands is disclosed. In this process, bitumen froth is extracted from tar sands using a water process without requiring the use of caustic soda. The froth is treated in a counter-current decantation circuit with a paraffini ...


2
Willem P C Duyvesteyn, Julia Rose Budden, Bernardus Josephus Huls: Biochemical treatment of bitumen froth tailings. BHP Minerals International, Hopgood Calimafde Kalil & Judlowe, June 13, 2000: US06074558 (45 worldwide citation)

A process for the biological treatment of bitumen froth tailings produced from a tar sands treatment and bitumen froth extraction process is disclosed. In this process bitumen froth tailings, containing native hydrocarbon metabolizing microorganisms, are mixed with a growth media to form an inoculum ...


3
Willem P C Duyvesteyn, Robert N Hickman: Treatment of copper sulfide concentrates. Willem P C Duyvesteyn, Hopgood Calimafde Kalil Blaustein & Judlowe, January 5, 1993: US05176802 (38 worldwide citation)

A hydrometallurgical method is provided for recovering copper from particulate copper sulfide flotation concentrate containing at least about 20% copper by weight as cuprous and cupric sulfide, a significant portion of the copper in the copper sulfide concentrate being in the cuprous state. The flot ...


4
Willem P C Duyvesteyn, Timothy Malcome Spitler, Bruce James Sabacky, Jan Prochazka: Processing aqueous titanium chloride solutions to ultrafine titanium dioxide. Altair Nanomaterials, G Peter Nichols, Brinks Hofer Gilson & Lione, August 27, 2002: US06440383 (37 worldwide citation)

A hydrometallurgical process is provided for producing ultrafine or nano-sized titanium dioxide from titanium containing solutions, particularly titanium chloride solutions. The process is conducted by total evaporation of the solution, above the boiling point of the solution and below the temperatu ...


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Willem P C Duyvesteyn, Raymond L Morley, James S Hanson: Method for obtaining bitumen from tar sands. Marathon Oil Canada Corporation, Holland & Hart, March 22, 2011: US07909989 (23 worldwide citation)

A method and a system for obtaining bitumen from tar sand are disclosed. The disclosed method can include two extraction steps, such as a first extraction step using a light aromatic solvent and a second extraction step using a volatile hydrocarbon solvent. The light aromatic solvent and the volatil ...


7
Willem P C Duyvesteyn, Julian Kift, Raymond L Morley: Processing asphaltene-containing tailings. Marathon Oil Canada Corporation, Holland & Hart, September 8, 2009: US07585407 (21 worldwide citation)

Embodiments of a method and a system for recovering energy, materials or both from asphaltene-containing tailings are disclosed. The asphaltene-containing tailings can be generated, for example, from a process for recovering hydrocarbons from oil sand. Embodiments of the method can include a flotati ...


8
Willem P C Duyvesteyn, Robert F Hogsett: Process for metal recovery from steel plant dust. AMAX, Michael A Ciomek, Eugene J Kalil, September 9, 1986: US04610722 (21 worldwide citation)

A process is provided for hydrometallurgical processing of steel plant dusts containing cadmium, lead, zinc, and iron values, along with impurities such as chloride and fluoride salts of sodium, potassium, magnesium, etc. The first step in the process involves leaching the dust in a mixed sulfate-ch ...


9
Simon O Fekete, Gordon R Wicker, Willem P C Duyvesteyn, Dien F Shieh: Acid leaching of nickeliferous oxide ores with minimized scaling. Amax, Michael A Ciomek, July 4, 1978: US04098870 (19 worldwide citation)

Nickel values contained in oxidic ores are recovered by leaching with sulfuric acid. The ore is slurried with water, preheated to a leaching temperature between about 230.degree. C and about 300.degree. C and the preheated slurry is fed to one or more vigorously agitated autoclaves, operating contin ...


10
Willem P C Duyvesteyn, Manuel R Lastra, Houyuan Liu: Method for recovering nickel from high magnesium-containing Ni-Fe-Mg lateritic ore. BHP Minerals International, Hopgood Calimafde Kalil & Judlowe, November 5, 1996: US05571308 (19 worldwide citation)

A method is provided for recovering nickel from high magnesium-containing lateritic ores which also contain iron. The ores which are referred to as saprolitic ores are subjected to leaching with a mineral acid from the group consisting of HCl, H.sub.2 SO.sub.4 and HNO.sub.3, HCl being preferred.