Preparation method of reagent-grade stannous chloride dehydrate crystals

Abstract

The invention provides a method for preparing reagent-grade stannous chloride dehydrate crystals from industrial-grade raw materials. The method comprises the following steps: melting industrial tin ingots and quenching the molten industrial tin ingots into tin flower; then enabling reaction between filtered industrial hydrochloric acid and tin hydroxide to produce stannic chloride pentahydrate; adding the tin flower into the stannic chloride pentahydrate solution; enabling heat-insulating reaction for 12-18 h at 100-105 DEG C; when the mass concentration of quadrivalent tin in the solution is detected to be less than 0.01%, concentrating under reduced pressure till the specific weight of the solution is 2.0-2.4; filtering the solution into a cooling device to be cooled for 12-20 h at 0-10 DEG C; then discharging; carrying out vacuum suction filtration and centrifugal separation to obtain the required reagent-grade stannous chloride dehydrate crystals. The preparation method is short in process route, simple to operate, easy for processing parameter control and relatively high in production efficiency; the obtained product can meet the standards of the reagent-grade (high-purity) stannous chloride dehydrate crystals without crushing or screening, and can satisfy the requirements of industries (such as chemical analysis, catalytic synthesis and PCB colloid-Pd sensitization) which demand much on the quality of stannous chloride.

Description

technical field [0001] The present invention relates to a preparation method of tin salt, in particular to a preparation method of reagent-grade stannous chloride dihydrate crystal, more specifically to a method for preparing reagent-grade stannous chloride dihydrate crystal by using industrial-grade raw materials . Background technique [0002] Tin protochloride dihydrate is an important tin chemical raw material, which is widely used in electroplating, catalytic synthesis, pesticide synthesis, chemical analysis and other industries. The traditional production method of stannous chloride dihydrate uses tin ingot as raw material, mainly contains chlorine gas method and hydrochloric acid method. The production method uses tin ingot as raw material, mainly contains chlorine gas method and hydrochloric acid method. [0003] Publication No. CN85106332 Chinese invention patent discloses the use of metal tin, chlorine and water in the presence of hydrochloric acid to react at 30-...

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Problems solved by technology

[0003] Publication No. CN85106332 Chinese invention patent discloses the use of metal tin, chlorine and water in the presence of hydrochloric acid to react at 30-105 degrees Celsius to generate tin chloride, and then add metal tin as a reducing agent, under the same conditions Produce tin protochloride, this process adopts controlled hypertoxic chlorine gas as raw material, there is potential safety hazard, and production process is not environmentally friendly; Notification number is the Chinese utility model patent of CN202022759U, although disclose adopting liquid chlorine to replace chlorine gas to prepare dichloride Tin can improve the safety performance of the production process, but there is still the risk of chlorine gas leakage, and because chlorine gas is highly corrosive when it meets water vapor, it is difficult to produce stannous chloride that meets the reagent grade

Analytical pure hydrochloric acid and high-purity tin ingot can be used to produce reagent-grade stannous chloride dihydrate, but there are disadvantages such as long reaction time between hydrochloric acid and tin (generally more than 48 hours), large acid loss, and high cost. The publication number is CN102849788A The Chinese invention patent application discloses that metal tin flower and hydrochloric acid with a concentration of 25-34wt% are used as raw materials, and an ultrasonic wave with a frequency of 20-30kHZ is used to synthesize a stannous chloride solution at room temperature in the next step, and then concentrated and crystallized to obtain chlorinated Although the introduction of ultrasonic waves shortens the reaction time for stannous crystals, hydrogen gas will be released when tin reacts with hydrochloric acid, and a large amount of hydrogen gas will be released in a short period of time, which requires high explosion-proof facilities in the workshop and has a large potential safety hazard; the publication number is CN104591268A. The invention application discloses a method for preparing high-grade stannous chloride by using low-tin waste slag. The method undergoes tedious multiple liquid preparation and impurity removal procedures, and the obtained high-grade stannous chloride is no matter the impurity index or the actual detection. None of the results can meet the requirements of reagent grade

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