阅读说明：本技术 一种测定锌铜混合液中锌和铜的方法 (Method for measuring zinc and copper in zinc-copper mixed solution ) 是由 彭海军 钟学明 李艳容 于 2020-06-12 设计创作，主要内容包括：本发明一种测定锌铜混合液中锌和铜的方法,以硫代硫酸钠和EDTA为滴定剂测定硫酸铜和硫酸锌混合液中的铜和锌的含量；首先,通过EDTA测定硫酸铜和硫酸锌混合液中锌和铜的合量；其次,通过硫代硫酸钠测定硫酸铜和硫酸锌混合液中铜的含量；最后,锌和铜的合量减去铜的含量,而获得锌的含量；采用滴定法测定锌铜混合液中的锌和铜,不需要使用大型仪器,测定的误差小,相对误差小于1％。(The invention relates to a method for determining zinc and copper in a zinc-copper mixed solution, which comprises the steps of determining the contents of copper and zinc in a copper sulfate and zinc sulfate mixed solution by taking sodium thiosulfate and EDTA as titrants; firstly, determining the total amount of zinc and copper in a copper sulfate and zinc sulfate mixed solution through EDTA; secondly, measuring the content of copper in the mixed solution of copper sulfate and zinc sulfate by using sodium thiosulfate; finally, the content of the copper is reduced by the total amount of the zinc and the copper, and the content of the zinc is obtained; the titration method is adopted to measure the zinc and the copper in the zinc-copper mixed solution, a large instrument is not needed, the measurement error is small, and the relative error is less than 1%.)

1. A method for measuring zinc and copper in a zinc-copper mixed solution is characterized by comprising the following steps: the method comprises the steps of determining the contents of copper and zinc in a mixed solution of copper sulfate and zinc sulfate by using sodium thiosulfate and EDTA as titrants; firstly, determining the total amount of zinc and copper in a copper sulfate and zinc sulfate mixed solution through EDTA; secondly, measuring the content of copper in the mixed solution of copper sulfate and zinc sulfate by using sodium thiosulfate; finally, the content of the copper is reduced by the total amount of the zinc and the copper, and the content of the zinc is obtained;

the method specifically comprises the following steps:

1) EDTA determination of the total amount of Zn and Cu

Transferring 10ml to 30ml of zinc-copper mixed solution into a 250ml conical flask by using a pipette, dropwise adding 1 to 2 drops of xylenol orange into the conical flask, and adding 20ml of hexamethylenetetramine buffer solution, wherein the solution is changed from yellow to purple; then 5ml of saturated sodium fluoride solution and a small amount of ascorbic acid are added into the bottle; titrating by using calibrated EDTA until the solution in the conical flask changes from purple to bright yellow, and obtaining the end point after 30 seconds of no fading;

2) determination of copper content with sodium thiosulfate

Transferring 10ml to 30ml of zinc-copper mixed solution into a 250ml conical flask, adding 20ml of deionized water for dilution, slowly dropwise adding ammonia water (1+1) into the conical flask until trace precipitates exist in the flask, stopping dropwise adding the ammonia water, adding 5ml of acetic acid-sodium acetate buffer solution into the flask, adding a certain amount of saturated sodium fluoride solution, a small amount of ascorbic acid and an excessive amount of potassium iodide solution (at the moment, the solution is dark yellow); titrating by using a calibrated sodium thiosulfate standard solution until the color in the bottle is changed from dark yellow to light yellow, continuously adding 2ml to 3ml of 0.5 percent starch solution into the bottle, at the moment, changing the solution from light yellow to blue, quickly adding 2ml of 10 percent KSCN solution into the bottle, and continuously titrating until the blue color disappears, wherein the end point is that the color is not faded for 30 s.

2. The method as claimed in claim 1, wherein the mixture of zinc and copper is obtained by diluting a mixture of copper sulfate and zinc sulfate in a volumetric flask, the concentration of zinc ions in the mixture of zinc and copper is 0.04 mol/L-0.06 mol/L, and the concentration of copper ions is 0.04 mol/L-0.06 mol/L.

Technical Field

The invention discloses a method for determining zinc and copper in a zinc-copper mixed solution, and particularly relates to a method for determining the contents of copper and zinc in a copper sulfate and zinc sulfate mixed solution by taking sodium thiosulfate and EDTA as titrants. The invention belongs to the technical field of zinc and copper determination.

Background

The existing method for measuring zinc and copper in the zinc-copper mixed solution needs to depend on large instruments such as an atomic absorption spectrometer, an ICP-atomic emission spectrometer and the like, and the measurement error is large and reaches 10 percent. Therefore, it is one of the urgent matters to establish a more efficient, economical and simple method for measuring zinc and copper in a mixed zinc-copper solution.

Aiming at the phenomenon of larger error of the existing method for measuring the zinc and the copper in the zinc-copper mixed solution, the invention establishes a more efficient, economic and simple method for measuring the zinc and the copper in the zinc-copper mixed solution by adopting a titration method, does not need large instruments, and has small measurement error which is less than 1 percent.

Disclosure of Invention

Aiming at the phenomenon of larger error of the existing method for measuring the zinc and the copper in the zinc-copper mixed solution, a more efficient, economic and simple method for measuring the zinc and the copper in the zinc-copper mixed solution by adopting a titration method is established.

The invention relates to a method for determining zinc and copper in a zinc-copper mixed solution, which comprises the steps of determining the contents of copper and zinc in a copper sulfate and zinc sulfate mixed solution by using EDTA and sodium thiosulfate as titrants; firstly, determining the total amount of zinc and copper in a copper sulfate and zinc sulfate mixed solution through EDTA; secondly, measuring the content of copper in the mixed solution of copper sulfate and zinc sulfate by using sodium thiosulfate; finally, the combined amount of zinc and copper is reduced by the copper content to obtain the zinc content:

the method specifically comprises the following steps:

1) EDTA determination of the total amount of Zn and Cu

Transferring 10ml to 30ml of zinc-copper mixed solution into a 250ml conical flask by using a pipette, dropwise adding 1 to 2 drops of xylenol orange into the conical flask, and adding 20ml of hexamethylenetetramine buffer solution, wherein the solution is changed from yellow to purple; then 5ml of saturated sodium fluoride solution and a small amount of ascorbic acid are added into the bottle; titrating by using calibrated EDTA until the solution in the conical flask changes from purple to bright yellow, and obtaining the end point after 30 seconds of no fading;

2) determination of copper content with sodium thiosulfate

Transferring 10ml to 30ml of zinc-copper mixed solution into a 250m L conical flask, adding 20ml of deionized water for dilution, slowly dripping ammonia water (1+1) into the conical flask until trace precipitates exist in the conical flask, stopping dripping the ammonia water, adding 5ml of acetic acid-sodium acetate buffer solution into the conical flask, adding a certain amount of saturated sodium fluoride solution, a small amount of ascorbic acid and an excessive amount of potassium iodide solution (at the moment, the solution is dark yellow), titrating by using a calibrated sodium thiosulfate standard solution until the color in the conical flask changes from dark yellow to light yellow, continuously adding 2ml to 3ml of 0.5% starch solution into the conical flask, at the moment, the solution changes from light yellow to blue, quickly adding 2ml of 10% KSCN solution into the conical flask, continuously titrating until the blue disappears, and taking the end point that the color does not fade for 30 s.

The method for measuring zinc and copper in the zinc-copper mixed solution comprises the steps of diluting the copper sulfate and zinc sulfate mixed solution by adopting a volumetric flask to obtain the zinc-copper mixed solution, wherein the concentration of zinc ions in the zinc-copper mixed solution is 0.04 mol/L-0.06 mol/L, and the concentration of copper ions in the zinc-copper mixed solution is 0.04 mol/L-0.06 mol/L.

The invention has the beneficial effects that: 1) the relative error is small: the invention adopts a titration method to measure the zinc and the copper in the zinc-copper mixed solution, the measurement error is small, and the relative error is less than 1 percent. 2) The process flow is short: the whole process only comprises 4 steps of sodium thiosulfate calibration, sodium thiosulfate copper content determination, EDTA calibration and EDTA zinc content determination. 3) The reagent cost is low: only a small amount of cheap hydrochloric acid and indicator are consumed. 4) The equipment is simple: only the usual equipment such as analytical balance, iodine bottles and pipettes need to be used. 5) The energy consumption is low: the method can realize the determination of zinc and copper in the zinc-copper mixed solution at room temperature, and only consumes energy for stirring and material transfer.

Detailed Description

The method for determining zinc and copper in a zinc-copper mixed solution according to the present invention will be further described with reference to the following specific examples.