Method for determination of iron in copper alloy

Abstract

A method for determination of iron in a copper alloy comprises the following steps: (1) a copper alloy sample is weighed and put into a conical flask, and HCl and H2O2 are used for heating to dissolve the sample; (2) the copper alloy sample solution is taken and slightly cooled, an ammonia solution is used to adjust pH value to 6.8-7.2, the copper alloy sample solution is filtered and washed with the ammonia water until the copper alloy sample solution is free of copper ions, and hydrochloric acid is used for washing a precipitate into a conical flask; (3) tin dichloride is used for reduction of the solution to yellowish; then water is added, a mixed acid of phosphoric acid and sulfuric acid is added, a few drops of a sodium tungstate indicator are added, and a titanium trichloride solution is added dropwise until the solution is blue; then a potassium dichromate standard titration solution is used for titration of the solution until the blue color disappears; then three drops of a sodium diphenylaminesulfonate indicator are added, and the potassium dichromate standard titration solution is used for titration of the solution until a stable purple color as the end point is reached. The reaction speed is fast, the end point is stable, does not change color and is easy to observe, and the accuracy is good; meanwhile the determination process is short, determination efficiency is high, the determination method is easy to grasp, used chemicals are simple, and the method has the advantages of low pollution, low requirements for equipment and environment and low determination cost.

Description

technical field [0001] The invention relates to a method for determining iron in copper alloys, in particular to a quantitative analysis method for determining iron in copper alloys by means of an oxidation-reduction capacity method. Background technique [0002] Copper alloy is an alloy composed of pure copper as the base and adding one or several other elements. Copper alloys are divided into many types. Among them, the alloy composed of copper and zinc is brass, the alloy of copper and nickel is white copper, and bronze is an alloy formed of copper and elements other than zinc and nickel, mainly tin bronze, aluminum Bronze, etc., while red copper is copper with a high copper content, and the total content of other impurities is less than 1%. As an alloying element in copper alloys, the accurate determination of iron content plays an extremely important role. [0003] At present, the determination of iron in copper alloys is usually carried out by sulfosalicylic acid met...

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Problems solved by technology

Plasma emission spectroscopy and other large-scale instrumental methods have high equipment costs and high environmental requirements. Frequent determination of high-content elements is not conducive to the long-term use of the instrument. It needs to be diluted step by step, which is not suitable for various units and factories. Efficiency Determination Requirements

In addition, there are absorption spectrophotometry, such as Zhang Chen, Xi Wujun, Wang Jingshuang "Determination of Iron in Copper Alloy by Flame Atomic Absorption Spectrophotometry" [J]. Chemical Analysis and Metrology, 2012, 21(4): 74-78. This kind of determination The method has not been separated by interference, and only masking agent is used for masking; matrix elements zinc and copper consume o-phenanthroline, which affects color development, requires less weighing, or multiple liquid separations to reduce interference, and strict requirements on color development time. lack of stability

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