Thiocarbamide-Citrate Electrolytes as an Alternative to Cyanide Electrolytes in Solving the Problems of Environmental Protection and Prevention of Emergency Situations

Abstract

A comparative analysis of the occupational hazard was done when working with widely known cyanide electrolytes and new thiocarbamide and citrate acid-based electrolytes. For this purpose, we made use of available reference data on maximum permissible substance concentrations, i.e. process solution components. Appropriate computations were done to define the environmental hazard of the electrolytes used for the application of silver, gold and copper coatings and also for the electrochemical silver polishing. Consideration was given to the reactions that proceed in cyanide and thiocarbamide-citrate bathes. The main drawbacks and advantages of given electrolytes have been established. Special attention was paid to the quality of galvanic products. It was proved that the suggested electrolytes are highly competitive with cyanide analogues as for their visual appearance, density and other characteristics of the condition of treated surface. These turned out to be labor saving and energy efficient and have substantially lower harmful effect on the human health and environment.

Gold-Reducing Cathode Reactions Kinetics in Acid Thiourea Electrolytes

“…Therefore, acidic thiourea-citrate electrolytes can be a successful solution to the problem of the replacement of the toxic cyanide electrolytes of the goldplating by less efficient but more ecologically friendly solutions. 20…”

A study of the impact of solid cast removable dentures with silver electroplating on the condition of patients

“…-1 point -inflammation of the gingival papilla -R -2 points -inflammation of the gingival (marginal) edge -M -3 points -inflammation of the entire mucous membrane of the alveolar process -A The formula for calculating the RMA index: where n = 24 (6-11 years old) n = 28 (12-14 years old) n = 30 (from 15 years) 3 -the maximum number of points Evaluation criteria of the PMA index: -up to 25% -gingivitis is mild -25-50% -gingivitis of moderate severity -more than 51% -gingivitis is severe At the second stage of research, silver electroplating was applied to the metal parts of the brace prosthesis according to the original technology developed at the Department of Technical Electrochemistry of the National Technical University «Kharkiv Polytechnic Institute» [12,13,14,15].…”

“…5. Anodic processing in the electrolyte, which included sulfuric and hydrochloric acids [12]. The temperature of the solution was 18-25⁰C, j a = 0.5-1.0 A/dm 2 or ε a = 0.0 ± 0.05 V, processing time -20-40 minutes, titanium cathodes.…”

“…12. Silvering in the electrolyte, the main components of which were silver salt (citrate or silver nitrate (I)), thiourea, citric acid and sodium selenium [12]. Temperature -18-35⁰C, j k = 0.5-1.0 A/dm 2 , processing time -40 minutes, anodes -silver.…”