The sample was decomposed by HCl and HNO3, and the absorbance of Ag was determined by air-acetylene flame AAS method in aqua regia (1+4) medium. Multiple coexisting elements do not interfere with the assay. When the Ag content is low and the sampling amount is large, there is background interference. This method is applicable to the determination of w(Ag)/10-6=1-500 (the instrument has a background correction device) and w(Ag)/10-6=5-500 (the instrument has no background correction device) in rocks and minerals. Second, reagent preparation Silver standard storage solution: A standard storage solution of 1000 μg/mnL Ag was prepared by the method of determining silver by a thiourea medium flame method. Silver standard solution: Pipette 50.0mL silver standard storage solution in a 500mL volumetric flask, dilute to the mark with HNO3 (1+99), and mix. This solution contained 100 μg/mL Ag. Third, the instrument and working conditions WFX-1E atomic absorption spectrometer. Silver hollow cathode lamp; lamp core 4 mA; wavelength 328.1 nm; spectral passband 0.2 nm; burner height 13 mm; air flow rate 7 L/min; acetylene flow rate 1.2 L/min. Fourth, the analysis steps Weigh 0.2-1.0g (accurate to 0.0001g) sample in a beaker, wet with a small amount of water, add 15-20mL HCl, heat at low temperature for about 10min, add 5mL HNO3, continue heating until decomposition and steam to near dry, remove Slightly cold, add 8 mL HCl, 2 mL HNO3 and a small amount of water, and heat to dissolve the salts. After the test solution is cooled, transfer it to a 50 mL volumetric flask, dilute to the mark with water, and mix. Stand still and clarify. Adjust the AAS instrument to the proposed working conditions, and take the test solution into the air-acetylene flame to determine the absorbance of Ag. The same batch is accompanied by a blank test. Drawing of the working curve: separately transfer the calculated amount of silver standard solution into two groups of 100 mL volumetric flasks, add 16 mL of HCl, 4 mL of HNO3, dilute to the mark with water, and mix. In the standard series, the mass concentrations of Ag were 0, 0.20, 0.40, 0.60, 0.80, 1.00 μg/mL, and 0, 1.0, 2.0, 3.0, 4.0, and 5.0 μg/mL, respectively. The sample solution was measured in the same batch, and the mass concentration of Ag was taken as the abscissa, and the corresponding absorbance was the ordinate, and the working curve was drawn. V. Calculation of analysis results General rule (ÏB2-ÏB1)×Vs wB/10-6=------------------ Ms Calculate the amount of Ag in the sample. Six, matters needing attention The same method as for the determination of silver by the hydrochloric acid medium flame method. Spirals are mainly used for stirring, mixing and other functions in pipeline transportation. The spiral surface of the screw conveyor has a solid spiral surface. , belt spiral surface and blade spiral surface transparent form. Screw Conveyor&Compactor,Quality Screw Machine,Automatic Conveying Feeder,Shaftless Screw Machine Wuxi Feiyiya Environmental Protection Technology Co., Ltd. , https://www.feiyya.com
The cold rolling mill is an advanced equipment that continuously rolls blades from strip steel. By adjusting the position (roll offset, feed height, roll pressure, guide wheel, etc.), it can roll out blades of various specifications required.
Advantages of cold rolling layout:
It has the advantages of high production efficiency, saving raw materials, good blade quality, high hole diameter, and good wear resistance.
The structures that affect the rolling shape include the material and thickness of the strip, the offset of the roll, the feeding height, the rolling force of the roll, the different specifications of the guide wheels and blades, and the increase in the temperature of the roll during the rolling process. After years of construction, the contract developed this continuous cold-rolled propeller, which has the advantages of smooth surface, high hardness, wear resistance, one-time forming, and continuous no welds.
Determination of silver by aqua regia flame method
First, the method mentions