Abstract: A method and apparatus for separating arsenic from an aqueous solution containing arsenic. The method includes the steps of contacting an arsenic-containing solution with a first portion of fixing agent to remove at least a portion of the arsenic. An arsenic-laden fixing agent is separated from the solution and the partially depleted solution is contacted with a second portion of fixing agent. The fixing agent can include a high surface area insoluble compound containing one or more of cerium, lanthanum, or praseodymium. Following removal of the arsenic, the arsenic-depleted solution can be further processed to separate a recoverable metal through metal refining. The arsenic-laden fixing agent can be filtered to recover and recycle a filtrate to the solution for additional treatment, as well as using a partially saturated fixing agent to remove arsenic from fresh solution.

Abstract: A method and apparatus for recovering a metal and separating arsenic from an arsenic-containing solution. The method includes contacting the arsenic-containing solution with a fixing agent that comprises a rare earth compound to produce an arsenic-depleted solution and an arsenic-laden fixing agent. The fixing agent comprises a rare earth-containing compound that can include cerium, lanthanum, or praseodymium. The fixing agent is separated from the arsenic-depleted solution and a recoverable metal is separated from one or more of the arsenic-containing solution and the arsenic-depleted solution. Recoverable metals can include metal from Group IA, Group IIA, Group VIII and the transition metals. The arsenic-containing solution can be formed by contacting an arsenic-containing material with a leaching agent. Arsenic-depleted solids formed during the leach can also be separated and recovered.

Abstract: A method and apparatus for removing arsenic from an arsenic-bearing material. The method includes the steps of contracting an arsenic-bearing material with an arsenic leaching agent to form an arsenic-containing solution and arsenic-depleted solids. The leaching agent can be an inorganic salt, an inorganic acid, an organic acid, and/or an alkaline agent. The arsenic-depleted solids are separated from the arsenic-containing solution, which is contacted with a fixing agent to produce an arsenic-depleted solution and an arsenic-laden fixing agent. The fixing agent comprises a rare earth-containing compound that can include cerium, lanthanum, or praseodymium. The fixing agent is then separated from the arsenic-depleted solution. A recoverable metal in the arsenic-depleted solids, arsenic-containing solution or arsenic-depleted solution can be separated and recovered. Recoverable metals can include metal from Group IA, Group IIA, Group VIII and the transition metals.

Abstract: An apparatus for treating an aqueous solution containing arsenic. The apparatus comprises a container that includes a housing, an inlet located at a first end of the housing and an outlet located at a second end opposite the first end. An outer wall extends between the first and second ends and enclosing a fluid flow path between the inlet and the outlet and an arsenic fixing agent is disposed in the fluid flow path. The arsenic fixing agent can include an insoluble rare earth-containing compound, more specifically, a compound comprising one or more of cerium, lanthanum, or praseodymium. The inlet and the outlet are adapted to be closed during transport and storage. The container is adapted to be sealed for long term disposal after exposure to an aqueous solution containing arsenic.

Abstract: An apparatus for treating an aqueous solution containing arsenic. The apparatus comprises a container that includes a housing, an inlet located at a first end of the housing and an outlet located at a second end opposite the first end. An outer wall extends between the first and second ends and enclosing a fluid flow path between the inlet and the outlet and an arsenic fixing agent is disposed in the fluid flow path. The arsenic fixing agent can include an insoluble rare earth-containing compound, more specifically, a compound comprising one or more of cerium, lanthanum, or praseodymium. The inlet and the outlet are adapted to be closed during transport and storage. The container is adapted to be sealed for long term disposal after exposure to an aqueous solution containing arsenic.