Determination of thiourea in copper electrorefining solutions

Summary

In the copper electrorefining process, chemical additives such as thiourea are utilized to enhance electrolytic refining and regulate the grain size of copper deposits. Precise quantification of thiourea is crucial for ensuring the quality of the refined copper. This requires its direct analysis in copper concentrates that contain sulfuric acid and trace amounts of chloride. However, the presence of chloride can interfere with the analysis.

This Application Note introduces a voltammetric method for the accurate quantification of thiourea in copper electrolytes. The main advantage of this method lies in its ability to precisely determine thiourea levels even in the presence of high chloride concentrations within the sample matrix.

With precise control over thiourea levels, the copper refining process can be adjusted more precisely, leading to improvements in the consistency and quality of the refined copper.

This method offers a simple and precise solution for maintaining optimal levels of thiourea.

Configuration

884 Professional VA manual for MME

2.884.0110

884 Professional VA manual for MME is the entry-level instrument for high-end trace analysis with voltammetry and polarography with the Multi-Mode Electrode pro or the scTRACE Gold. The proven Metrohm electrode methods in combination with a completely new design of potentiostat/galvanostat and the extremely high-performance viva software opens up new perspectives for the determination of heavy metals. The potentiostat with a certified calibrator readjusts itself automatically before each measurement, thus guaranteeing maximum precision.Determinations with rotating disc electrodes can also be performed with the instrument, e.g. determinations of organic additives in electroplating baths with "Cyclic Voltammetric Stripping" (CVS), "Cyclic Pulse Voltammetric Stripping" (CPVS), and chronopotentiometry (CP). The replaceable measuring head enables rapid changes between various applications with different electrodes.The viva software is required for control, data acquisition, and evaluation.The 884 Professional VA manual for MME is supplied with extensive accessories and a measuring head for the Multi-Mode Electrode pro. Electrode set and viva license need to be ordered separately.

Multi-Mode Electrode pro

6.1246.120

Mercury electrode for voltammetry. Can be operated as DME, SMDE or HMDE.

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Sample

Cu electrorefining electrolyte

Experimental

Figure 1. 884 Professional VA manual for MME

Add the sample and the electrolyte solution into the measuring vessel and degas it for 5 min. The interfering effect of chloride is mitigated through the addition of masking analyte. The determination is carried out using parameters listed in Table 1. Quantification is done with the 884 Professional VA manual for MME (Figure 1) using two standard additions with thiourea standard addition solutions.

**Table 1.** Parameters
Parameter	Setting
Mode	DME
Start potential	-0.9 V
End potential	-1.75 V
Sweep rate	15 mV/s
Peak potential Au(I)	-1.45 V

Electrodes

Multi-Mode Electrode pro

Results

Figure 2. Determination of thiourea in an electrorefining electrolyte containing 0.75 mg/L thiourea

Figure 2 presents the result of the determination in an electrorefining solution containing 0.75 mg/L thiourea.

**Table 2.** Result
Sample	Thiourea in mg/L
Cu electrorefining electrolyte	0.71

Liên hệ

CÔNG TY TNHH METROHM VIỆT NAM

Tòa nhà Park IX, số 08 Đường Phan Đình Giót, Phường 2, Quận Tân Bình
Thành phố Hồ Chí Minh

Liên hệ

Internal references: AW DE4-0164-102004

Determination of thiourea in copper electrorefining solutions

Precision meets simplicity with the Multi-Mode Electrode pro

Summary

Configuration

884 Professional VA manual for MME

2.884.0110

Multi-Mode Electrode pro

6.1246.120

Sample

Experimental

Electrodes

Results

CÔNG TY TNHH METROHM VIỆT NAM

Liên hệ