Preparation method of special cyanide-free zinc-plating brightener for sylvite system

Abstract

The invention discloses a preparation method of a cyanide-free zinc-plating brightener special for a sylvite system. The preparation method comprises the following steps that (A) 13.6-27.2 g of organic aldehyde compound, 45.8-75.8 g of secondary solvents and 300-500 ml of water are added into a reaction vessel, then heating is conducted, and the temperature rises to 40-50 DEG C, 10.5-22.5 g of reductive drug solution is dropped, and the dropping time is 50-80 minutes; (B) after dropping of the reductive drug solution is completed, the temperature of the reaction vessel rises to 80-85 DEG C, and after heat preservation and stirring for reacting are conducted for 6-10 hours under the temperature of 80-85 DEG C, a first step reaction intermediate can be obtained; (C) then 12.4-24.6 g of phytic acid aqueous solution is slowly dropped into the first step reaction intermediate, and the dropping time is 30-40 minutes; and (D) after dropping is completed, the reaction temperature is 70-90 DEGC, constant temperature is kept for 3-4 hours, cooling and recovery are conducted, and the cyanide-free zinc-plating brightener is obtained. According to the brightener obtained through the preparation method of the cyanide-free zinc-plating brightener, the deposition rate of a plating can be increased stably, brittleness of the plating is low, the working temperature range is wide, environment pollution is very little, and the brightener is beneficial to environmental protection.

Description

technical field [0001] The invention relates to a preparation method of an electroplating brightener, in particular to a preparation method of a cyanide-free galvanizing brightener specially used for a potassium salt system. Background technique [0002] Currently commonly used alkaline galvanizing processes include cyanide-free alkaline galvanizing and cyanide galvanizing. Although cyanide galvanizing has relatively high comprehensive performance, due to the high toxicity of cyanide galvanizing solution, it is difficult to treat wastewater, seriously pollute the atmosphere and groundwater, and have poor environmental protection performance. Alkaline cyanide-free galvanizing, because the toxicity of the plating solution is relatively small, the waste water is easier to treat, and at the same time, it has better dispersion ability and non-corrosion than acid galvanizing, so alkaline cyanide-free galvanizing is advocating environmental protection and energy saving. society is...

AI Technical Summary

Problems solved by technology

Traditional cyanide-free zincate galvanizing additives have a narrow range of bright current density, slow deposition rate, narrow temperature range (usually not higher than 40°C), brittleness when the coating exceeds 15 microns, difficulty in plating cast iron, and poor dispersion ability of the plating solution. Poor, dark coating, rough and loose grains of the coating texture, and the difference in thickness of the deposited layer in the high and low current areas is also relatively large, and there are even shortcomings such as rough high areas and missing plating in low areas.

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