초록 ▼

A hydrometallurgical process utilizing an atmospheric calcium chloride leach to selectively recover from various metal feed stocks (consisting of elemental metals, metal oxides, metal ferrite, metal hydroxide, metal carbonates, metal sulfate/sulfur compounds, and their hydrates, specifically includi

A hydrometallurgical process utilizing an atmospheric calcium chloride leach to selectively recover from various metal feed stocks (consisting of elemental metals, metal oxides, metal ferrite, metal hydroxide, metal carbonates, metal sulfate/sulfur compounds, and their hydrates, specifically including but not limited to EAF Dust KO61) zinc, lead, cadmium, silver, copper and other valuable metals to the exclusion of iron, magnesium, halogen salts and other unwanted elements. The process solves the problem of iron and magnesium leach solution contamination because iron is unexpectedly converted to magnetite. The heavy metals are cemented out of solution using zinc or other selected dust at a pH of 6 or greater under unique and unexpected conditions, which do not require acid. Simonkolleite/zinc-oxychloride/zinc-hydroxide is produced from the purified zinc chloride complex pregnant leach solution and is converted directly to high purity active rubber grade 99+% zinc oxide having small particle size and high surface area. The products are metal concentrates suitable for: metal refiner/processors, production of elemental metal, or other conversion processes. The process removes Arsenic and Fluorides in the feed material. The process also solves the problem of chloride contamination in the zinc oxide and prevents heavy metal contaminants in the hydrometallurgically produced zinc oxide derived from feed stocks containing chlorides or when chlorides are used to leach the metal bearing feed stocks. In one embodiment, calcium and/or magnesium compounds are added to the iron bearing waste to increase the recovery of zinc and other non-ferrous metals and to produce an iron bearing flux. The process is environmentally friendly and fully recycles all streams.

대표청구항 ▼

1. A leach process utilizing a chloride leach solution for leaching a selected metal from a metal bearing feed stock to produce a pregnant chloride leach solution suitable for selective metal recovery, comprising the steps of:providing a metal bearing feed stock containing iron oxides and containing

1. A leach process utilizing a chloride leach solution for leaching a selected metal from a metal bearing feed stock to produce a pregnant chloride leach solution suitable for selective metal recovery, comprising the steps of:providing a metal bearing feed stock containing iron oxides and containing a metal oxide (MO) wherein M is selected from the group consisting of Zn, Cd, Cu, Ag, Sn, Ni, and Pb;contacting said feed stock with a chloride leach solution comprising CaCl 2 and water with a specific gravity in a range of 1.45 to 1.55 wherein the specific gravity of the chloride leach solution is controlled by the addition or removal of water to form a complex solution; andmaintaining the concentration of CaCl 2 in said complex solution so that the CaCl 2 will react, at atmospheric pressure and at a temperature below the boiling point of the complex solution, with the MO to form a calcium-metal-chloride complex according to the formula: 2 +2MO+2H 2 O→[Ca ++ +2MCl 3 − ]+2CaOH 2 without solubilizing substantially all of the Fe present in the complex solution. 2. The leach process of claim 1 wherein the metals bearing feed stock comprises one or more feeds selected from the group consisting of metal furnace dusts, smelting dusts, waste sludges, mill tailings, ores which contain metal oxides, metal hydroxides, metal ferrites, metal sulfates/metal sulfites, carbonates, metal bearing materials containing chlorides or fluorides, zinc oxide recovered from pyrolysis or furnace operations, waste metal bearing materials, dust including zinc ferrite, sludges from metal plating baths, sludges from electrowinning tank operations, copper or other heavy metals, BOF flue dust containing 3-20% zinc and heavy metal content, jarosite from mining operations, waste water treatment metal bearing sludges and cakes, zinc ferrite tailings, electric arc furnace dust containing 10-60% or more zinc, zinc smelter dust, copper smelter dust, iron ore containing greater than 5% zinc and heavy metals, blast furnace or BOP dust containing 5% or more zinc, zinc smelter dust, copper smelter dust, metal bearing ores containing iron or sulfates, metal concentrates containing sulfur compounds, waste by-product streams containing oxides or hydroxides, metal bearing materials containing chlorides, copper dross, lead dross, cyanide bearing plating waste, plating waste, arsenic bearing ores and wastes, gold ores with sulfur, copper electrolysis anode sludge, metal ores incinerator fly ash, boiler fly ash, spent metal catalyst, metallic dross, uranium ores, gold bearing ore, silver bearing ore and sludges, feed stocks or solution containing fluoride, feed stocks or solution containing arsenic, galvanized scrap metal, zinc bearing scrap, copper bearing scrap, scrap electronic component and aluminum pot liner. 3. The leach process of claim 1 wherein the process converts iron oxide and ferrites to magnetite. 4. The leach process of claim 1 wherein the chloride leach solution further comprises sodium chloride and potassium chloride. 5. The leach process of claim 1 wherein the chloride leach solution wherein the calcium chloride concentration is at least 16% and is less than the saturation point for calcium chloride. 6. The leach process of claim 1 wherein the chloride leach solution is fully liquid at a selected temperature of the process and is below the saturation point. 7. The leach process of claim 1 wherein the temperature of the process is above 65 degrees Celsius and below the boiling point of the complex solution. 8. The leach process of claim 1 wherein the pH of the complex solution is above 3.5 and below 9.0. 9. The leach process of claim 1 wherein the specific gravity of the chloride leach solution allows only 2 to 100 ppm iron to solubilize in the complex solution. 10. The leach process of claim 1 wherein a portion of the metals feed stock is initially undissolved in the complex solution and wherein the process further comprises the steps o f:separating the initially undissolved portion of the metals feed stock from the complex solution;washing the initially undissolved portion of the metals feed stock with a leach solution; andwashing the initially undissolved portion of the metals feed stock with water at a temperature of at least 70 degrees Celsius to force some of the initially undissolved portion of the metals feed stock into the complex solution to obtain an enhanced metal yield recovery and a purified solid cake. 11. The leach process of claim 1 wherein 70 to 100% by weight of the selected metal from the metal feed stock is reacted to form the calcium-metals chloride complex. 12. The leach process of claim 1 wherein the complex solution is washed with a wash solution having a temperature greater than a crystal formation temperature of salts present in the complex solution. 13. The leach process of claim 1 wherein the process produces magnetite when the metals feed stock contains one or more materials selected from the group consisting of: iron oxide, ferrites and iron hydroxides.