In this paper, the principle, reagents, equipment and test methods of spectrophotometry, ion chromatography and mercuric nitrate titration for the determination of chlorine content in copper concentrate are compared and discussed, aiming at choosing the right method in the detection process of copper concentrate.
Comparison of experimental principles
The principle of spectrophotometry is to leach copper concentrate samples with water, and under the action of 100℃ constant temperature magnetic stirrers leach 1.5h, after filtration, in ethylene glycol and nitric acid environment with silver nitrate to form silver chloride suspension, the use of spectrophotometer to determine the chlorine content of the sample. The principle of ion chromatography is to decompose the copper concentrate sample with sulfuric acid, in which chloride ions will be separated from the copper concentrate sample with water vapor escape, absorbed by the absorption solution, determined by ion chromatography to qualitatively retain time, and calculate the chlorine content by working curve method [3]. The principle of mercuric nitrate titration method is to leach copper concentrate samples with potassium sulfate solution, rock for 1h at 90 ° C ~95 ° C, filter, add excess ethanol in the acidic solution, titrate chloride ions in the test solution with mercury nitrate standard solution, and use diphenylcarbazone indicator and slightly excessive mercury to form purple complex to judge the end point.
By comparison, it is found that the principle of spectrophotometry and mercuric nitrate titration is relatively simple, and ion chromatography is complex compared with spectrophotometry and mercuric nitrate titration.
By comparison, it is found that the principle of spectrophotometry and mercuric nitrate titration is relatively simple, and ion chromatography is complex compared with spectrophotometry and mercuric nitrate titration.
Reagent comparison
The reagents used for spectrophotometry are primary water, nitric acid, silver nitrate solution, ethylene glycol, chloride ion standard reserve liquid, etc. The reagents used for ion chromatography are primary water, sodium hydroxide, sulfuric acid, sodium hydroxide solution, chlorine standard solution, etc. The reagent used for mercury nitrate titration is primary water, hydrogen peroxide, ethanol, nitric acid, sodium hydroxide solution, potassium sulfate solution, sodium chloride standard solution, mercury nitrate standard solution, diphenylcarbazone and so on. By comparing the reagents used in the three methods, it is found that the mercuric nitrate standard substance used in the mercuric nitrate titration method is a highly toxic substance, and the reagents used in the spectrophotometry and ion chromatography are daily used reagents in the laboratory, and do not belong to serious drugs.
Comparison of instruments and equipment
The instruments and equipment used in the spectrophotometry method are spectrophotometers (Shanghai Meishe Instrument Co., LTD.), constant temperature magnetic stirrer, analytical balance (accurate to 0.0001g), other commonly used laboratory instruments and equipment (such as colorimetric tube, glass rod, volumetric bottle, measuring cup, plastic head dropper, etc.); The instruments and equipment used in ion chromatography are ion chromatograph (with conductivity detector), water vapor distillation device, nylon filter membrane, syringe, analytical balance (accurate to 0.0001g), other commonly used laboratory instruments and equipment (such as round-bottom flask, glass rod, volumetric bottle, measuring cup, plastic head dropper, etc.); The instruments and equipment used in the mercuric nitrate titration method are pH test paper, analytical balance (accurate to 0.0001g), constant temperature water bath oscillator, burette, and other commonly used laboratory instruments and equipment (such as volumetric bottles, plastic head droppers, conical bottles, measuring cups, etc.).
By comparing the instruments and equipment used in the three methods, it was found that the instrument and equipment used in ion chromatography was more expensive, and the instrument and equipment used in spectrophotometry and mercury nitrate titration was lower than that used in ion chromatography.
By comparing the instruments and equipment used in the three methods, it was found that the instrument and equipment used in ion chromatography was more expensive, and the instrument and equipment used in spectrophotometry and mercury nitrate titration was lower than that used in ion chromatography.
Comparison of test methods
Sample
Take the copper concentrate samples YP001 and YP002 (sample particle size≤100μm), dry the samples in the oven at 100℃~105℃ for 1h, take them out and place them in the dryer, cool to room temperature, and then set aside.
Lank test
Make a blank test with the sample.
Spectrophotometry
Weigh sample, dissolve sample, titration and data analysis were carried out according to the analytical steps in “Research on the Method of Determination of Chlorine in Copper Concentrate by Spectrophotometry”. The accuracy test results were shown in Table 1 and the precision test results were shown in Table 2.
Table 1 Test results of spectrophotometric accuracy
| Sample | Determination results (mg/kg) | Mean value (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.12 | 0.12 | 5.66 |
| 0.13 | |||
| YP002 | 0.46 | 0.46 | 1.52 |
| 0.47 |
Table 2 Precision test results of spectrophotometry
| Sample | Determination results (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.12、0.13、0.13、0.12、0.13、0.13、0.12 | 4.25 |
| YP002 | 0.46、0.45、0.48、0.46、0.47、0.46、0.47 | 2.10 |
Lon chromatography
According to GB/T3884.12-2023 “Copper concentrate chemical analysis method Part 12: determination of fluorine and chlorine content of ion chromatography and spectrophotometry” analysis steps of ion chromatography, weighing sample, dissolution sample, configuration standard curve and data analysis, accuracy test results are shown in Table 3, precision test results are shown in Table 4.
Table 3 Accuracy test results of ion chromatography
| Sample | Determination results (mg/kg) | Mean value (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.12 | 0.12 | 0 |
| 0.12 | |||
| YP002 | 0.46 | 0.47 | 3.01 |
| 0.48 |
Table 4 Precision test results of ion chromatography
| Sample | Determination results (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.12、0.12、0.13、0.12、0.13、0.13、0.14 | 5.95 |
| YP002 | 0.45、0.47、0.45、0.46、0.46、0.48、0.47 | 2.40 |
Mercuric nitrate titration method
According to the analysis steps of Q/CCICGXJS02021-2023 “Copper Concentrate Chemical analysis method for determination of chlorine content of mercury nitrate titration Method”, the weighing sample, dissolution sample, titration and data analysis are carried out. The accuracy test results are shown in Table 5, and the precision test results are shown in Table 6.
Table 5 Accuracy test results of mercuric nitrate titration
| Sample | Determination results (mg/kg) | Mean value (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.13 | 0.13 | 0 |
| 0.13 | |||
| YP002 | 0.45 | 0.46 | 3.07 |
| 0.47 |
Table 6 Precision test results of mercuric nitrate titration
| Sample | Determination results (mg/kg) | Relative standard Deviation (%) |
| YP001 | 0.14、0.12、0.13、0.13、0.12、0.12、0.12 | 6.26 |
| YP002 | 0.46、0.48、0.47、0.46、0.45、0.46、0.47 | 2.10 |
Comparison of results
The comparison results of accuracy and precision of the three methods are shown in Table 7.
Table 7 Comparison of accuracy and precision of the three methods (unit: 0%)
| Sample Method | YP001 | YP002 | ||
| Accuracy | Precision | Accuracy | Precision | |
| Spectrophotometry | 0.12 | 4.25 | 0.46 | 2.10 |
| Lon Chromatography | 0.12 | 5.95 | 0.47 | 2.40 |
| Mercuric nitrate titration method | 0.13 | 6.26 | 0.46 | 2.10 |
By using the above three methods to detect copper concentrate (YP001, YP002) samples, it is found that the accuracy measurement results of the three methods are within the tolerance range, and the precision measurement results also meet the relevant requirements. No matter which method is used for detection, it can achieve better accuracy and precision.
Conclusion
To sum up, the laboratory can choose the appropriate method according to the actual situation of the laboratory before the detection of chlorine content in copper concentrate. Because through the analysis of the three methods of the test principle can not judge the amount of manpower and material input, at the same time through the experiment, the accuracy and precision of the three methods are not much different, so the laboratory can choose from the reagents and equipment. If the laboratory considers the environmental protection and safety of the reagent, it can choose spectrophotometry or ion chromatography to determine the chloride ion content in copper concentrate; If the laboratory funds are limited and can not bear the expensive equipment costs, you can choose spectrophotometry or mercuric nitrate titration method to determine the chloride ion content in copper concentrate.
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