Abstract: Biological treatment process removes free and metal complexed cyanides, and thiocyanate through oxidations. Even high concentrations of these pollutants are workable. Toxic heavy metals are absorbed and adsorbed within a biofilm. This process has been adapted to and performs well at high cyanide concentrations (e.g., even above about 100 mg/L and high pH (e.g., even higher than about 9.5). Mixed cultures of adapted strains of Pseudomonas are utilized to perform biological oxidation within the system. End products of oxidation include carbonates, sulfates, and nitrates. The pH is neutralized by metabolism of, or by, intermediate reaction products. The biological processes can be utilized as a pretreatment or post-treatment process in conjunction with chemical processes.

Abstract: A process for treating refractory ores combines pressure oxidation treatment of the ore with cyanidation and carbon-in-pulp recovery. Pressure oxidation is carried out under acidic conditions, at elevated temperatures and pressure. Before cyanidation, the oxidized slurry is subjected to a multiple stage washing operation to remove excess acid and heavy metals generated during the pressure oxidation. Such heavy metal removal lowers the subsequent cyanide usage and makes the process more economical. Cyanidation is carried out in a conventional manner, and it has been found that carbon-in-pulp recovery leads to greatly enhanced recovery of gold when compared to other conventional methods, such as zinc precipitation.

Abstract: Cyanides, thiocyanates and metal cyanide complexes present in an aqueous solution can be biologically degraded by certain mutant strains of the species Pseudomonas paucimobilis. Such microorganisms are useful in the biological treatment of cyanide-containing wastewaters.Pseudomonas paucimobilis mudlock was deposited at the ATCC on Nov. 3, 1982, and granted accession No. 39204.

Abstract: Cyanides, thiocyanates and metal cyanide complexes present in an aqueous solution can be biologically degraded by certain mutant strains of the species Pseudomonas paucimobilis. Such microorganisms are useful in the biological treatment of cyanide-containing wastewaters.Pseudomonas paucimobilis mudlock was deposited at the ATCC on Nov. 3, 1982, and granted accession No. 39204.

Abstract: A method for removing low concentrations of soluble copper in the form of cupric cation and cuprocyanide and cupricyanide anions comprises first adding ferric cation, or ferrous cation and a soluble oxidizing agent, in an amount in excess of the stoichiometric amount required to form the ferric salts of the cuprocyanide and cupricyanide anions, and after a predetermined time adding an environmentally acceptable soluble precipitant to precipitate substantially all of the remaining excess ferric cation. By this procedure, very small concentrations of soluble cupric cation and the ferric salts of the cuprocyanide and cupricyanide anions, which are typically present in such low concentrations that they remain essentially permanently suspended in colloidal solution, are removed by the insoluble ferric compound which is present in much higher concentrations.