A kind of preparation method of electronic grade stannous sulfamate

Abstract

The invention provides a method for preparing electronic-grade stannous sulfamate. The method includes the steps that a sulfamic acid solution with the mass concentration being 5%-13% is prepared at first, and then an anion heterogeneous exchange membrane is adopted as the ion exchange membrane in a diaphragm electrolyzer and is further pretreated so that the anion dissolving-out quantity can be smaller than 20ppm; afterwards, the sulfamic acid solution is injected to the cathode region and anode region of the diaphragm electrolyzer; a metallic tin plate with the thickness being 10-50mm is used as the anode, and a metallic tin plate with the thickness being 10mm is used as the cathode to conduct diaphragm electrolysis at the temperature of 10-40 DEG C or below and at the electric current density of 1.0-5.0A / dm<2>; solid sulfamic acid is regularly added at the cathode region so that the sulfamic acid concentration can be kept to be 3% or above; and electrolysis is stopped when the tin ion concentration of the anode region is 5%-10%, and after the solution drained from the anode region is filtered, a stannous sulfamate solution at the required concentration can be prepared directly or evaporation and concentration crystallization is carried out. By adoption of the preparation method, the operational path is short, product purity is high, the metal recovery rate is also high, production cost is low and three-waste emission can be avoided.

Description

technical field [0001] The present invention relates to a kind of preparation method of tin salt, relate in particular to a kind of preparation method of tin sulfamate, more specifically relate to a kind of electronic grade tin sulfamate which can be widely used in electronic products and tin plate Tin preparation method. Background technique [0002] Stannous sulfamate is one of the important compounds of tin, widely used in electroplating and other electronic industries. As a new type of electroplating material, tin sulfamate plating solution has high electrical conductivity, good stability, and The advantages of fast tin deposition, wide range of current density, and low COD of wastewater, compared with the tin plating of the tin methanesulfonate system, have the characteristics of low cost and no harm to the environment due to raw material production (environmental protection during the production of methanesulfonic acid High risk, high price), in the case of increasin...

AI Technical Summary

Problems solved by technology

[0003] The preparation method of the publicly disclosed stannous sulfamate at present has: (1) stannous sulfate adds ammonia water and hydrolyzes and becomes stannous hydroxide, after repeatedly washing away impurity ions such as sulfate, react with sulfamic acid to synthesize stannous sulfamate ; (2) The reaction of sulfamic acid and barium hydroxide produces barium sulfamate, and the reaction of barium sulfamate and stannous sulfate produces stannous sulfamate and barium sulfate; (3) Chinese patent with authorized announcement number CN 102303850 B The disclosed preparation method is to prepare stannous oxide first, then wash the stannous oxide, mix the washed stannous oxide with sulfamic acid, then add pure water, reducing agent and tartaric acid to heat and react to obtain sulfamic acid stannous acid crude solution, then add activated carbon to the solution for adsorption and impurity removal, after filtering through impurity removal, add pure water to prepare the stannous sulfamate solution of required concentration; the common defect of the above three methods is that the operation Long cycle, many impurity ions and difficult to handle, easy to pollute the environment, the product quality is difficult to meet the quality requirements of tinning process of electronic products and tinplate and other industries for tin sulfamate quality requirements, in addition, due to the long production process, the direct recovery rate of metal Low, so that the production cost is high, which also restricts the promotion of tin sulfamate tin plating process