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The composition of matte is relatively complex, if the content of noble metals is directly determined by inductively coupled plasma atomic emission spectrometry after acid dissolution, the content of impurity elements is too high, the interference is serious, leading to the large deviation of results. In this experiment, the lead assay method was first used to remove most of the impurity elements in the matte sample in a high-temperature molten state to enrich the precious metal into the lead buckle, and then the lead was removed from the lead buckle to obtain the precious metal particles after ash blowing. The results were corrected using second assay, the combined particles were dissolved in nitric acid to separate gold from other elements, and the mass of the gold particles was weighed, added an appropriate amount of hydrochloric acid solution to the gold separation solution and continued heating treatment, and then the concentrations of gold, lead, bismuth, copper, and palladium in the gold separation solution were measured by inductively coupled plasma atomic emission spectrometer under selected optimal instrument operating conditions. The contents of gold, silver, and palladium in the matte sample were calculated using the given formula. The effects of lead oxide dosage, ash blowing temperature and matrix interference on the determination results were discussed. When the amount of lead oxide added was 200 g and the ash blowing temperature was 890 °C, the test results were the best. The interference test showed that the high or low content of silver in the sample would not affect the determination of Au, Pb, Bi, Cu, and Pd. The test results showed that the recovery of silver was 97. 7%--100%, the recovery of gold was 98. 6%--102%, and the recovery of palladium was 98.0%--102%. this method was easy to operate, and had good accuracy and precision the RSD values were between 1. 1% and 3. 3%, and could meet the needs of actual detection. [ABSTRACT FROM AUTHOR]

The sampling and preparation process of cathode copper has great influence on the iron content in the test results, and the method of extracting copper plate as specified in the standard can meet the requirements of sampling precision. Different cleaning surface, drilling method, drill material, preparation method and iron removal steps have greater impact on the iron content in the test results, using scanning electroscope and Xray energy spectrum is used to study the iron pollutants in the sample and the reason affecting the changes in iron content is obtained. The sampling and preparation process for reducing iron pollution in the copper cathode is including tungsten steel drill bit, strict cleaning grinding equipment, four step method removal iron and change the weight of test sample, and so on. [ABSTRACT FROM AUTHOR]

The quality of Cu in the lead matte is easy to change, which affects the value judgment of the goods. Through the comparison experiment, the key influencing factors were found, and a method of preserving samples in vacuum was proposed, which points out the solution for the trade friction from the technical way. [ABSTRACT FROM AUTHOR]

A highly efficient way for the direct (trans)esterification of acyl acids (esters) and alcohols in a strict 1 : 1 ratio using a zirconocene complex (1, 1 mol%), a strong Lewis acid of good water tolerance, as a catalyst under solvent-free conditions has been developed. A wide range of acid and alcohol (esters) substrates undergo (trans)esterification to produce carboxylic ester motifs in moderate to good or excellent yields with good functional tolerance, such as that towards C–Br as well as C=C and C≡C bonds. And complex 1 can be recycled six times without showing a significant decline in catalytic efficiency. It was demonstrated that cyclandelate, which is used to treat high blood pressure as well as heart and blood-vessel diseases, can be directly synthesized on a gram scale with 81% yield (6.70 g) using complex 1. [ABSTRACT FROM AUTHOR]