Inductively coupled plasma emission spectrometry (ICP-AES) has low detection limit, wide linear range and multi-element
The advantages of simultaneous determination have now become the main means of rare earth element analysis. Computer controlled single pass scan
ICP-AES is widely used in the determination of rare earth elements due to its flexible line selection.
Experimental part:
Equipment and working conditions:
HK-8100 single-channel scanning emission spectrometer. Wavelength range 190 ~ 500nm,
Plasma generator: Chernytna
The maximum power is 1300W, continuously adjustable, and the fixed operating frequency is 27.12 MHz.
Working conditions: high frequency power 0. 65 kW, reflected power is zero. Argon flow: Plasma flow
15 L/ min,
The atomization gas flow rate is 110 L/min, and the auxiliary gas flow rate is 013 L/min.
Observation height: 15 mm above the load coil.
Lifting amount: 1 1 4 mL/min.
Integration time: 1 s.
Peak search steps: standard 24 steps, sample 10 steps.
Standard solution and main reagents:
All rare earth element single element standard stock solutions are light
Spectral purity reagents are prepared, and the oxides of each rare earth element are:
La 2 O 3, CeO 2, Pr 4 O 11, Nd 2 O 3, Sm 2 O 3, Eu 2 O 3,
Gd 2 O 3, Tb 4 O 7, Dy 2 O 3, Ho 2 O 3, Er 2 O 3, Tm 2 O 3
, Yb 2 O 3, Lu 2O 3, Y 2 O 3 and Sc 2 O 3. Dilute the stock solution step by step to prepare rare earth mixture
Each rare earth standard medium of the standard working solution is 1.2 mol/L HCl. HNO 3 (Analytical grade), 1.
20 mol/L, tartaric acid containing ρ= 10g/L. EGTA (analytical purity), 0.1 mol/L.
Sample analysis process:
Weigh 1.000 g air-dried sample into a high alumina crucible, add 3 to 4 g Na 2 O 2, mix well,
The surface is covered with a layer of flux and melted in a muffle furnace heated to 700 ℃ for 10 minutes. After taking out and cooling
, Put the crucible into the furnace which has been added with 10 mL 0.1 mol/L EGTA, 5 mL triethanolamine and 80 mL distilled water.
In the cup, and heat to boiling. Take it off and wash out the crucible after cooling. Filter to 20 g/L NaOH solution
Wash the sediment 5-8 times, and wash the sediment 2 times with distilled water. Remove the precipitate and filter paper into the original beaker,
Add 10 mL of 6 mol/L HCl, heat and stir until the precipitate is completely dissolved, after cooling, filter, and
mL 20 g/L tartaric acid-washed filter paper, dilute the filtrate to 100 mL, add a small amount of ascorbic acid to reduce the solution to nothing
color. The solution was transferred to a cation exchange column equilibrated with 0.6 mol/L HCl, and the
L HNO 3 (contains tartaric acid, 20 g/L) 80 mL and 1.2 mol/L HCl 40 mL to wash impurities,
Then use 6 mol/L HCl 80 mL to elute the rare earth, the solution is evaporated to 1 mL on the electric hot plate, and then remove
After cooling, transfer to a 10 mL colorimetric tube, dilute to the mark, shake well and place on the HK-8100 single-channel scanning spectrometer
Determination.
Results and discussion:
This method has been used to determine the national standard samples of polymetallic nodules and deep-sea sediments GBW 07313,
GBW07249, the result is in good agreement with the standard ＆#118alue, and the relative standard deviation of each element is 1.3% ～ 5.
3%, the reproducibility of some lower content elements such as Tb and Tm is significantly improved. Prove the accuracy of this method
And precision meet the requirements.
CHINSE