摘要:
Systems and methods are provided for the removal and disposal of arsenic from an aqueous medium. The systems and methods include the removal of arsenic from a source by contact with either a chemically treated natural or synthetic zeolite, for example a ferric-loaded zeolite. The spent zeolite is disposed of at an appropriate arsenic disposal site. A system for monitoring and maintaining an arsenic removal/disposal system by an off-site provider is also disclosed.
摘要:
Methods and apparatuses are provided for the removal and destruction of ammonia from an aqueous medium. The methods and apparatuses include the removal of ammonia from an aqueous medium by contact with either natural or synthetic zeolite. The spent zeolite is re-generated for continuous use, while the ammonia is concentrated as ammonium sulfate, and ultimately destroyed via combustion. A system for monitoring and maintaining an ammonia removal system by an off-site provider is also disclosed.
摘要:
Systems and methods are provided for the removal and disposal of chromium form an aqueous medium. The systems and methods include the removal of chromium from a source by contact with either natural or synthetic zeolite that has been modified with a ferrous ion or other like substance. The spent zeolite is disposed of and replaced with freshly modified zeolite. In some cases the systems and methods are performed under de-oxidizing conditions.
摘要:
The present invention is a process for selectively precipitating molybdenum in a form that is substantially free from vanadium impurities. The molybdenum is precipitated in the form of ammonium octamolybdate which has a molybdenum to vanadium ratio of about 400:1 in an initial crystallization and a ratio of about 1300:1 in a subsequent recrystallization.
摘要:
High purity ammonium dimolybdate or molybdenum oxide is produced by the pressure oxidation of low grade molybdenite concentrates or molybdenum intermediates. The process entails nearly complete oxidation of the sulfide minerals while optimizing the process chemistry and autoclave conditions to solubilize as little of the molybdenum values as possible. The autoclave discharge 12 is then subjected to a leaching step, either an alkaline leach 50, 400 or ammonium leach 250 process, before or after a liquid/solid separation step 20, 220, 410. The solution is then subjected to (a) filtration 60, 410, solvent extraction 70, 440, crystallization 90,450, and calcination 120, 480 or (b) filtration 260, 280, crystallization 290, and calcination 320 to produce a product suitable for chemical-grade molybdenum oxide 125, 325, 485.
摘要:
The invention comprises the treatment of metal oxides and mixed metal oxides and metal sulfides in a vertical tube reactor system having a downcomer section and a riser section in order to oxidize and dissolve the metal values in aqueous slurry primarily in the downcomer section and introducing a reducing agent comprising a formate species and reducing the dissolved metal values in the riser section. The reduced metal values are then separated with the gangue values from the product solution downstream from the vertical tube reactor system. The reduced metal values may then be separated from the gangue material by conventional solid separation techniques, such as flotation.
摘要:
According to the present invention, improved dissolution of nickel and cobalt and thus improved recovery of those desired metal values is achieved by modifying the ore recovery processes wherein sulfuric acid leaching at elevated temperatures is used to dissolve the nickel and cobalt. In particular, according to the present invention, processes are provided wherein the sulfuric acid and ore are contacted at substantially ambient temperature prior to subsequent heating to attain the elevated temperatures of the sulfuric acid leach. Practice of the present invention has been found to result in improved metal value recovery.
摘要:
Disclosed is process for the separation of tungsten from molybdenum and more particularly from ammonium molybdate solutions. The method comprises dissolving technical grade molybdenum trioxide in an aqueous ammonium hydroxide solution and further adding certain metal generating compounds to the aqueous solution thereby generating a tungsten-containing precipitate. Calcium, iron and manganese are the preferred metal generating compounds of the invention. Certain temperature and pH values of the system, as disclosed, are preferred for the precipitation of the tungsten from the ammonia molybdate solution.