A Zero-Waste Process for the Treatment of Spent Potliner (SPL) Waste

This work presents a deep analyses of an environmentally friendly process to recover all valuable minerals contained in the spent potliner (SPL) such as graphite carbon and aluminum fluoride (AlF3) and production of sodium sulfate (Na2SO4) and gypsum (CaSO4) when H2SO4 is used as the leaching agent. The level of emission of hazardous gases such as HCN (weak acid) and HF are minimized by direct scrubbing of the HCN in aqueous AgNO3 solution to produce a stable silver cyanide (AgCN) product. The HF can be recovered as a liquid by condensation and used within the process and/or in production of metal fluorides such as the highly-soluble potassium fluoride (KF); a main source of fluoride in industry. Almost pure CO2 gas is also recovered from the process gas streams.

A new chromogenic and fluorescent chemosensor based on a naphthol–bisthiazolopyridine hybrid: a fast response and selective detection of multiple targets, silver, cyanide, sulfide, and hydrogen sulfide ions and gaseous H2S

This optical probe selectively recognized the titled analytes by the color changes, which are applicable by solution or solid kits.

A closed-loop electrogenerative recycling process for recovery of silver from a diluted cyanide solution

A closed-loop process for the complete recovery of silver from a diluted silver cyanide solution has been constructed based on an electrogenerative process.

Silber(I)-cyanid-Komplexe mit Aminen und Azaaromaten

Silver cyanide can be treated with liquid amines or azaaromaticsLto give crystalline complexes of various compositions, among them complexes of the simple type cyanido(amine)silver(I):L=isobutylamine and 4-picoline. Other AgCN:Lratios obtained were: 1:2 (benzylamine and 4-benzylpiperidine), 2:1 (2,4-lutidine), 2:3 (morpholine and 3,4-lutidine) and 3:4 (3,5-lutidine). The packing diagrams were analyzed in terms of Ag–Ag and Ag–CN contacts and N–H···N hydrogen bonds. The contacts often give rise to chains, which are sometimes linked to layers by hydrogen bonds.

Potentials of some Waste Biomaterials as Sorbents for Gold- and Silver-Cyanide Removal from Aqueous Matrices

Plating, printed circuit board, jewellery units, photofinishing and mining industries emanate large-volume low-tenor effluents containing metal-cyanide (MxCN) like gold-and silver-cyanide. Since metal moiety of MxCN being precious, non-renewable and finite resource; their complete removal from effluents is the key. Biosorption has immense potential of becoming efficient and economical alternative to recover the wasted metal resource over conventional methods. Twenty-eight low-cost biomaterials obtained from diverse sources were screened for gold-and silver-cyanide uptake. Study revealed that maximum uptake of both MxCN took place at acidic pH. Based on maximum uptake, Rice Husk (RH) andEicchorniaroot (ER) biomass were selected for gold-and silver-cyanide sorption, respectively, for further studies. Optimal conditions for sorption were: pH (4.0-7.0), biosorbent quantity (1-3%), rate of uptake (40 min) and initial MxCN concentration (5-500 μmol). Biosorption data obtained conformed to Freundlich and Langmuir adsorption models (R2>0.98). NaOH acted as an efficient desorbing agent (>95%).