Rapid analysis method of lead in gold mud

Abstract

The invention relates to a rapid analysis method of lead in gold mud. The method comprises the following steps: processing a sample by nitric acid, aqua regia, sulfuric acid, and a mixed acid of nitric acid and sulfuric acid in sequence, after the acid is smoked and evaporated, adding diluted sulfuric acid, boiling to dissolve the salts, adding excess sodium hyposulfite to reduce gold to zero valent and precipitate silver; allowing the system to stand still to carry out aging, filtering, washing the precipitate by diluted sulfuric acid and water; dissolving the precipitate by an acetic acid-sodium acetate buffer solution, filtering, recovering gold and silver, adding a xylenol orange indicator into the filtrate, dropwise adding EDTA until the color of the solution changes from purple-red to light yellow, wherein the color change shows that the titration end point is reached, and finally calculating the lead content. In the provided method, sodium hyposulfite is used to reduce gold and precipitate silver so as to effectively separated gold and silver from lead, thus the interference of gold and silver on the end point is avoided, moreover, the operation is largely simplified, and precise and stable analysis results can be obtained by the provided method.

Description

technical field [0001] The invention relates to a rapid analysis method for lead, in particular to a rapid analysis method for lead in gold mud. Background technique [0002] Gold mud is an important intermediate product in the process of gold smelting. It is a black and similar muddy substance obtained from the cyanide-containing liquid by adding reducing substances. In addition to gold and silver, it is mainly composed of copper, iron, lead, zinc, etc. metal composition. [0003] At present, the traditional determination methods of lead include EDTA titration, sodium acetate bottom solution polarography, pyrogallol red absorptiometry and flame atomic absorption method. These analytical methods are relatively mature and have a wide range of applications. However, the content of gold and silver in the gold mud is relatively high. When the traditional determination method is used to analyze the lead content, the gold and silver seriously interfere with the titration analysi...

AI Technical Summary

Problems solved by technology

But this method is not applicable to the analysis of lead content in gold mud, reason is to have following drawback: the first, after sulfuric acid fumes, chloroauric acid decomposes incompletely, remains the gold of a small amount of compound state, adds sulfuric acid acidification precipitation lead During the process, due to the long aging time, the valence state of gold ions is high and the particle size is large, it is easy to be wrapped and adsorbed by lead sulfate precipitation, and it is difficult to separate from lead in the subsequent treatment process.

Second, during titration, after adding the indicator, the solution will turn red and black, which interferes with the judgment of the titration end point

Third, silver will exist in the form of silver chloride and silver sulfate, which cannot be effectively removed, affecting the formation of lead sulfate crystals, and is not easy to separate from lead, affecting the titration analysis results

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