Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B11/00—Obtaining noble metals
  • C22B11/04—Obtaining noble metals by wet processes

Definitions

• the invention relates to a process for the extraction of precious metals from dilute aqueous or non-aqueous solutions which contain salts of base metals and / or other low-volatility inorganic or organic compounds.
• the precious metals that can be extracted include silver, gold and the platinum metals.
• aqueous and non-aqueous solutions occur in many areas, the precious metal content of which has to be obtained with the greatest possible separation of additional fiber present, such as base metal salts, neutral salts or low-volatile organic compounds.
• the dissolved noble metals can be precipitated from aqueous or water-miscible solutions by reduction into the elemental state and can be sent to the further processing known per se.
• This reduction and thus the extraction of the noble metal concentrates can be carried out by means of electrical current, by means of base metals such as zinc, iron or aluminum, or by means of reducing compounds such as hydrazine or sodium boranate leads.
• this reduction method has shortcomings, such as the often incomplete precipitation, the introduction of additional metals which pollute wastewater and the reduction of the copper, which is usually present in considerable quantities, the precipitation of base metal hydroxides, and the formation of inflammable hydrogen gas.
• the reduction reactions cannot usually be carried out in organic solutions. For organic solutions, especially for liquid waste from homogeneous catalytic processes of oxo synthesis, combustion and pyrolysis processes have been proposed for converting the partly highly diluted noble metals contained therein into concentrates.
• DE-AS 29 11 193 has disclosed a process especially for the recovery of rhodium from residues of oxo synthesis, in which the residues are reacted with sulfur or a sulfur-releasing compound and the precipitate which forms is worked up.
• This process has the disadvantage that it cannot be used in aqueous solutions, the sulfur usually forms additional reaction products which disrupt the work-up and is often absorbed by the organic solvents in such large amounts that it hinders their further processing.
• the precious metals are precipitated by adding elemental tellurium or reducible tellurium compounds to the solution at temperatures of 100 to 250 ° C and the precipitate is worked up in a known manner.
• the addition of the elemental tellurium or the reducible tellurium compounds is advantageously carried out at temperatures from 120 to 200 ° C., in the case of solutions with low boiling points of the organic solvents and in aqueous solutions preferably in closed pressure containers.
• the low-boiling solvent e.g. to be replaced on the distillation route by a higher-boiling one.
• elemental tellurium or reducible tellurium compounds in contrast to the known processes and in contrast to the known sulfur and also selenium, are precipitants for noble metals from dilute solutions, which are highly effective with regard to the noble metal yields and are generally applicable both in aqueous and in organic solutions, as well as the excellent selectivity between precious metals and base elements, which include copper here.
• the resulting precipitates which contain the noble metals in elemental form or in the form of tellurides, can be produced in a known manner, for example by roasting processes or by wet chemistry be worked up.
• the recovered tellurium or the tellurium-containing fraction can always be added to the precipitation process again, so that the tellurium consumption is very low, apart from the low drag-out losses.
• the tellurium thus represents a regenerable Zementationsstoff.
• Tellurium has the farther advantage that it from the organic waste solutions is practically not absorbed, for example, the O xo synthesis, so that the liberated precious metal organic solvent can be burned safely if necessary.
• the inventive method is both delmetalliten for aqueous E, which may also contain additional cations and anions such as halides, cyanides, sulfates, thiosulfates or phosphates, applicable as well as organic solvents containing, for example, alcohols, aldehydes, chlorinated hydrocarbons or organophosphorus compounds can.
• the amount of tellurium added depends primarily on the precious metal content of the solutions. It can be determined by simple experiments.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

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ID=6166679

Family Applications (1)

Country Status (11)

Cited By (1)

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• 1982
  • 1982-06-24 DE DE3223501A patent/DE3223501C1/de not_active Expired
• 1983
  • 1983-06-03 AT AT83105497T patent/ATE21706T1/de not_active IP Right Cessation
  • 1983-06-03 DE DE8383105497T patent/DE3365627D1/de not_active Expired
  • 1983-06-03 EP EP83105497A patent/EP0097842B1/fr not_active Expired
  • 1983-06-09 US US06/502,726 patent/US4687514A/en not_active Expired - Lifetime
  • 1983-06-15 JP JP58105984A patent/JPS5916938A/ja active Granted
  • 1983-06-20 BR BR8303257A patent/BR8303257A/pt not_active IP Right Cessation
  • 1983-06-21 ZA ZA834535A patent/ZA834535B/xx unknown
  • 1983-06-22 PT PT76914A patent/PT76914B/pt unknown
  • 1983-06-22 ES ES523500A patent/ES523500A0/es active Granted
  • 1983-06-22 AR AR293407A patent/AR229963A1/es active
  • 1983-06-23 CA CA000431081A patent/CA1204597A/fr not_active Expired

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