{
    "title": "Dithiobiuret Gold Extraction",
    "inventor_name": "Loghman Moradi (et al.)",
    "publication_year": 2016,
    "device_name": "Novel Dithiobiuret-Based Extractant for Gold and Palladium Recovery",
    "goal": "Recover and recycle gold (and palladium) from electronic waste efficiently, cheaply and with low environmental impact.",
    "problem_addressed": "Conventional gold recovery uses large volumes of toxic cyanide or aqua regia, which are costly, environmentally damaging and slow.",
    "concept_summary": "A single-step solvent extraction process that uses a dithiobiuret-derived extractant in a mild acidic mixture (acetic acid, hydrochloric acid and a small oxidant) to selectively complex gold and palladium. The metal-laden organic phase is stripped in one stage, eliminating scrubbing steps and allowing the aqueous solution to be recycled.",
    "detailed_description": null,
    "category": "Chemistry & Chemical Processes",
    "principles": [
        "solvent extraction",
        "selective complexation",
        "acid leaching",
        "single-stage stripping"
    ],
    "scientific_domains": [
        "Chemistry",
        "Materials Science",
        "Environmental Engineering"
    ],
    "mechanisms_of_action": [
        "Dithiobiuret derivative forms strong complexes with Au(III) and Pd(II) in chloride-rich acidic media",
        "Complexes partition into the organic phase, leaving base metals behind",
        "A single stripping step releases the precious metals from the organic phase"
    ],
    "materials": [
        "acetic acid",
        "hydrochloric acid",
        "oxidant (e.g., hydrogen peroxide)",
        "dithiobiuret-based extractant",
        "water"
    ],
    "energy_sources": [],
    "inputs": [
        "electronic waste (circuit boards, scrap chips)",
        "hydrochloric acid solution",
        "acetic acid",
        "oxidant"
    ],
    "outputs": [
        "recovered gold",
        "recovered palladium",
        "recycled aqueous extractant",
        "untouched base-metal residues"
    ],
    "claimed_performance": "Gold stripped from circuits in ~10 seconds; extraction efficiency ~=99.9 % in ~2 minutes; only 100 L of extractant solution needed per kilogram of gold versus 5,000 L of aqua regia; solution cost ~=$0.50 / L.",
    "experimental_evidence": "The article states that gold is stripped in about 10 seconds and that the new solution can extract one kilogram of gold using only 100 L of solution, all recyclable. The patent claims 99.9 % extraction of gold and palladium in a single stage within two minutes.",
    "replication_status": null,
    "keywords": [
        "gold extraction",
        "palladium recovery",
        "e-waste recycling",
        "solvent extraction",
        "dithiobiuret",
        "acid leaching"
    ],
    "related_technologies": [
        "hydrometallurgy",
        "solvent extraction systems",
        "electronic waste processing"
    ],
    "controversy_level": "low",
    "confidence_score": 0.9,
    "practicability_score": 0.8,
    "fringe_score": 0.1,
    "evidence_strength": 0.5,
    "risk_score": 0.2,
    "trl_estimate": 5,
    "source_urls": [
        "http://newswise.com/articles/turning-electronic-waste-into-gold",
        "http://www.sciencedaily.com/releases/2016/01/160128122901.htm"
    ],
    "organizations": [
        "University of S (Chemistry Department)",
        "U.S. Patent Office"
    ],
    "applications": [
        "large-scale gold recovery from printed circuit boards",
        "palladium recovery from electronic scrap",
        "recycling of precious metals from industrial waste streams"
    ],
    "limitations": [
        "Requires handling of strong acids and oxidants",
        "Long-term stability and reuse cycles of the extractant not demonstrated",
        "Scale-up and continuous-flow operation not yet proven"
    ],
    "open_questions": [
        "How many recycling cycles can the extractant undergo before performance degrades?",
        "What is the full environmental impact of the spent aqueous phase?",
        "Can the process be integrated into existing e-waste recycling facilities cost minimal retro-fit?"
    ],
    "red_flags": [],
    "evidence_quotes": [
        "Gold is stripped out from circuits in about 10 seconds, leaving the other metals intact.",
        "One kilogram of gold can be extracted using only 100 litres of solution, all of which can be recycled over again.",
        "The overall cost of this solution is only 50 cents a litre.",
        "The high percentage of extraction of gold and palladium (about 99.9%) can be achieved in one stage.",
        "The extraction kinetic of palladium and gold ... works in substantially two minutes in many cases."
    ]
}