Provided is a water-insoluble crosslinked structure with an excellent metal-adsorbing effect. The crosslinked structure is formed by crosslinking a first linear polymer and a second linear polymer. The first linear polymer has a plurality of pendant groups represented by Formula (a). The second linear polymer has a plurality of pendant groups represented by Formula (a). Some of the plurality of pendant groups in the first linear polymer and some of the plurality of pendant groups in the second linear polymer are bonded to each other via a crosslinker. In the formula, ring Z represents a heterocycle containing a nitrogen atom as a heteroatom, R.sup.1 represents a single bond or an alkylene group having from 1 to 10 carbons, and Q.sup.+ represents a counter cation.

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This application pertains to methods of recovering metals from metal sulfides that involve contacting the metal sulfide with an acidic sulfate solution containing ferric sulfate and a reagent that has a thiocarbonyl functional group, wherein the concentration of reagent in the acidic sulfate solution is sufficient to increase the rate of metal extraction relative to an acidic sulfate solution that does not contain the reagent, to produce a pregnant solution containing the metal ions.

An electrochemical leaching system for recovering metals from electronic waste comprises an electrochemical cell configured to produce a hydrogen peroxide-enriched electrolyte. A power supply is in electrical communication with the electrochemical cell and a leaching reactor is configured to contain fragmented electronic waste and to produce a metal-enriched electrolyte from the fragmented electronic waste. The electrochemical cell and the leaching reactor are in fluid communication with each other. Related methods are also disclosed.

This application pertains to methods of recovering metals from metal sulfides that involve contacting the metal sulfide with an acidic sulfate solution containing ferric sulfate and a reagent that has a thiocarbonyl functional group, wherein the concentration of reagent in the acidic sulfate solution is sufficient to increase the rate of metal extraction relative to an acidic sulfate solution that does not contain the reagent, to produce a pregnant solution containing the metal ions.