Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

A system for recovering rare earth elements from coal ash includes a leaching reactor, an ash dryer downstream of the leaching reactor, and a roaster downstream of the ash dryer that is cooperatively connected to both the leaching reactor and the ash dryer. Coal ash is mixed with an acid stream such that rare earth elements present in the coal ash are dissolved in the acid stream, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. Mixing of the coal ash with the acid stream can occur in a leaching reactor and heating of the leachate can occur in a roaster. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.

Various embodiments provide a leaching solution monitoring module comprising a first leaching solution distribution system interface, a flow meter in fluid communication with the first leaching solution distribution system interface, the flow meter in fluid communication a 3-way pressure regulator, and a second leaching solution distribution system interface in fluid communication with the 3-way pressure regulator.

Various embodiments provide a leaching solution monitoring module comprising a first leaching solution distribution system interface, a flow meter in fluid communication with the first leaching solution distribution system interface, the flow meter in fluid communication a 3-way pressure regulator, and a second leaching solution distribution system interface in fluid communication with the 3-way pressure regulator.

The present disclosure provides a method for recovering metal from metal-containing waste material by leaching. In the method comprising providing aqueous solution (14), providing leaching agent precursor, providing a source of external energy (10), treating the aqueous solution (14) with the external energy (10) to form reactive species, reacting the leaching agent precursor with the reactive species to form a leaching agent and to obtain a leaching solution, providing metal-containing material, reacting the metal-containing material with the leaching solution to obtain soluble metal complexes, and recovering the metal complexes. The present disclosure also provides a device for recovering metal by leaching.

The present disclosure provides a method for recovering metal from metal-containing waste material by leaching. In the method comprising providing aqueous solution (14), providing leaching agent precursor, providing a source of external energy (10), treating the aqueous solution (14) with the external energy (10) to form reactive species, reacting the leaching agent precursor with the reactive species to form a leaching agent and to obtain a leaching solution, providing metal-containing material, reacting the metal-containing material with the leaching solution to obtain soluble metal complexes, and recovering the metal complexes. The present disclosure also provides a device for recovering metal by leaching.

A method for recovering rare earth elements (REE) from a leach solution. The method includes determining the concentration of a first plurality of contaminates in the leach solution, adding a first amount of oxalic acid to the leach solution and allowing it to react for a first period of time to form a first precipitant and a first liquor, maintaining the pH of the first liquor between 1.5 and 3 by the addition of an alkali base, removing the first precipitant, adding a second amount of oxalic acid to the first liquor and allowing it to react for a second period of time to form a second precipitant and a second liquor, maintaining the pH of the second liquor between 1.5 and 3 by the addition of the alkali base, and removing the second precipitant.

An improved method for recovering metals from spent supported catalysts, including spent supported hydroprocessing catalysts. The method and associated processes comprising the method are useful to recover spent supported catalyst metals used in the petroleum and chemical processing industries. The method generally involves a combination of a pyrometallurgical and a hydrometallurgical method and includes forming a potassium carbonate calcine from the spent supported catalyst containing Group VIIIB/Group VIB/Group VB metal compound(s) combined with potassium carbonate, and extracting and recovering soluble Group VIB metal and soluble Group VB metal compounds from the potassium carbonate calcine.

Abstract: Described herein is a process for obtaining rare earth elements from coal-based resources. Advantages of this process include low energy demands, application of environmentally-friendly solvents, and high purities of obtained rare earth elements.