1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB
2、ED HEREIN CAN BE HAZARDOUS. SAFETY DATA SHEETS (SDS) OR EXPERIMENTAL SAFETY DATA SHEETS (ESDS) FOR ALL OF THE MATERIALS USED IN THIS PROCEDURE SHOULD BE REVIEWED FOR SELECTION OF THE APPROPRIATE PERSONAL PROTECTION EQUIPMENT (PPE). COPYRIGHT 1992, 2016 UOP LLC. All rights reserved. Nonconfidential U
3、OP Methods are available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, USA. The UOP Methods may be obtained through the ASTM website, www.astm.org, or by contacting Customer Service at serviceastm.org, 610.832.9555 FAX, or 610.832.9585 PHONE. Nickel
4、, Molybdenum, Phosphorous, Cobalt, and Aluminum in Fresh Catalysts by ICP-OES UOP Method 925-16 Scope This method is for determining nickel, molybdenum, phosphorus and cobalt in fresh gamma-alumina supported catalysts; and nickel (Ni), molybdenum (Mo), phosphorus (P), cobalt (Co) and aluminum (Al) i
5、n fresh silica-alumina supported catalysts of known composition by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The method is suitable for determining nickel over a range of 1 to 10 mass-%, molybdenum over a range of 5 to 20 mass-%, phosphorus (as phosphate only) over a range
6、of 0.5 to 25 mass-%, cobalt over a range of 1 to 5 mass-%, and aluminum over a range of 5 to 50 mass-%. Catalysts containing alpha- or theta-alumina phases cannot be analyzed by the method. Nickel bearing catalysts that contain tungsten are analyzed by UOP Method 924. References UOP Method 918, “Col
7、lection and Grinding of Adsorbents and Catalysts for Analysis,” www.astm.org UOP Method 924, “Nickel, Tungsten and Aluminium in Fresh Catalysts by ICP-AES,” www.astm.org UOP Method 954, “Loss on Ignition (LOI) for Fresh, Regenerated, Used, and Spent Catalysts, Catalyst Supports, and Adsorbents,” www
8、.astm.org UOP Method 999, “Precision Statements in UOP Methods,” www.astm.org Perkin Elmer WinLab32 for ICP Instrument Control Software Manual Outline of Method Samples are ground using UOP Method 918, with alumina supported samples being dissolved using sulfuric acid, while silica-alumina supported
9、 samples are dissolved using sulfuric and hydrofluoric acids. The resulting sample solution is aspirated into an ICP-OES instrument and the element concentrations determined by comparison to a matrix-matched standard solution. Sample results are reported on a volatile-free basis, based on a 500 C LO
10、I (UOP Method 954, “Loss on Ignition (LOI) for Fresh, Regenerated, Used, and Spent Catalysts, Catalyst Supports, and Adsorbents”). Aluminum is determined on silica-alumina supported catalysts only. If desired, the results can be reported on an oxide basis also. 2 of 7 925-16 Apparatus References to
11、catalog numbers and suppliers are included as a convenience to the method user. Other suppliers may be used. Balance, readable to 0.0001 g Beaker, quartz, low form, 250-mL, Ace Glass, Inc., Cat. No. 5334-14 Beaker, PTFE, 250-mL, Fisher Scientific, Cat. No. 02-586-1H Crucible, wide form, 17 mL, porce
12、lain, Coors No. 60135, Fisher Scientific, Cat. No.FB-965-J Cylinders, graduated, polypropylene, 10- and 50-mL, Fisher Scientific, Cat. Nos. 08-572A and -572C, respectively Flasks, volumetric, Class A, 100-, 200-, 500- and 1000-mL, Fisher Scientific, Cat. Nos. 13-756-694, -695, -697 and -698, respect
13、ively, several of each required Funnel, disposable, 55-mm diameter, Fisher Scientific, Cat. No. 10-320A Hot plate, variable heat to at least 400 C, Fisher Scientific, Cat. No. 11-100-49H Inductively Coupled Plasma-Optical Emission Spectrometer, computer controlled, having a bandpass of 0.010 nm (FWH
14、M) or better, and covering the wavelength range specified in Table 2. The instrument must have the ability to use internal standards and perform background corrections, and must measure the internal standard response concurrently with each element response. A Perkin-Elmer 7300DV spectrometer with a
15、corrosion resistant sample introduction system, or its equivalent, is required. Pipets, total volume, Class A, 5-, 7-, 8-, 10-, 15-, 20-, 25-, 30- and 50-mL, Fisher Scientific, Cat. Nos. 13-660-5E, 13-646-42, -43, 13-660-5F, -5M, -5H, -5J, -5S, and -5K, several of each required. Alternatively, a dig
16、ital pipettor may be used. Pipets, total volume, 1-5 mL, 1-10mL, Eppendorf pipet Cat. No. 4920000105, 4920000113 Pipet filler, Fisher Scientific, Cat. No. 13-681-102A Regulator, argon, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-580 Regulator,
17、 nitrogen, two-stage, high purity, delivery pressure range 30-700 kPa (4-100 psi), Matheson Tri-Gas, Model 3122-580 Watch glass, 100-mm, glass, for 250-mL beaker, Fisher Scientific, Cat. No. 02-612D Watch glass, 100-mm, PTFE, Cat. No. 02-617-1E Reagents and Materials References to catalog numbers an
18、d suppliers are included as a convenience to the method user. Other suppliers may be used. References to water mean deionized or distilled water. Aluminum solution, 1000-g/mL, Spex Certiprep, Inc, Cat. No. PLAL2-2X Argon, 99.995% minimum purity, ICP feed gas Cobalt solution, 1000-g/mL, Spex Certipre
19、p, Inc, Cat. No. PLCO2-2X Gloves, neoprene, Fisher Scientific, Cat. Nos. 11-391-129A through -129E for sizes 7 through 10, respectively 3 of 7 925-16 Hydrofluoric acid, concentrated, trace metals grade, VWR, Cat. No. EM-HX0628-7 Molybdenum solution, 1000-g/mL, Spex Certiprep, Inc, Cat. No. PLMO9-2X
20、Nickel solution, 1000-g/mL, Spex Certiprep, Inc, Cat. No. PLNI2-2X Nitric acid, concentrated, trace metals grade, VWR, Cat. No. EM-NX0408-2 Nitrogen, 99.99% minimum purity, water/oil free, ICP optics purge gas Phosphorus solution, 1000-g/mL, Spex Certiprep, Inc, Cat. No. PLP9-2X Scandium metal solut
21、ion, aqueous, 10,000-g/mL, SPEX CertiPrep, Inc., Cat. No. PLSC2-3X, for use as an internal standard Scandium internal standard, aqueous, 100-g/mL. To prepare 100 mL, pipet 1 mL of the 10,000- g/mL scandium metal solution into a 100-mL volumetric flask. Fill to the mark with deionized water. Cap and
22、invert several times to mix. Store in a 125-mL polypropylene bottle. The solution should remain stable for two months. Sulfuric acid, concentrated, trace metals grade, VWR, Cat. No. EM-SX1248-6 Yttrium solution, 1000-g/mL, Spex Certiprep, Inc, Cat. No. PLY2-2X. Not required if the spectrometer speci
23、fied in Apparatus is used. Procedure Caution: All subsequent steps involving additions of acids and heating of samples and digests must be performed in a properly operating fume hood, using appropriate precautions. Gloves, safety glasses, goggles, and/or face shield, and other appropriate personal p
24、rotective equipment must be worn. Consult safety data sheet (SDS) and local regulations for each material used. The analyst is expected to be familiar with general laboratory practices, the technique of ICP-OES, and the equipment being used. Dispose of used supplies and samples in an environmentally
25、 safe manner according to applicable regulations. Preparation of Calibration Standards Since the catalyst composition is known, a single standard may be prepared and used that matches the composition of the catalyst. The concentrations of nickel, molybdenum, phosphorus, cobalt and/or aluminum are de
26、termined by calculation. For adequate calibration the sample must be within 10% (relative) of the standard concentration. Each catalyst type must have its own standard, matched to the catalyst composition. For example, for a catalyst with a nominal composition of 4 mass-% nickel oxide, 24 mass-% mol
27、ybdenum trioxide, 65 mass-% alumina and 7 mass-% phosphorous pentoxide, and using an original sample mass of 0.2 g diluted to 500 mL; the resulting sample solution would contain approximately 12-g/mL nickel, 65-g/mL molybdenum, 140-g/mL aluminum and 15 g/mL phosphorous. A standard would be prepared
28、as close as possible to those nickel, molybdenum aluminum and phosphorous concentration. See Table 1 for recommeded dilutions to be used for different nickel, molybdenum and phosphorous concentrations on the catalyst. Prepare a standard for the above example as follows: 1. Pipet 2 mL of 1000-g/mL ni
29、ckel solution, 7.5 mL of 1000-g/mL molybdenum solution, 15 mL of 1000-g/mL aluminum solution and 2 mL of 1000-g/mL phosphorous solution into a 100-mL volumetric flask. 2. Add 2 mL of sulfuric acid. 3. Pipet 2 mL of 100-g/mL scandium solution into the flask as an internal standard (see Notes). 4 of 7
30、 925-16 If a spectrometer other than that listed in Apparatus is used, yttrium can be substituted as the internal standard. 4. Allow the flask to cool to ambient temperature and dilute to volume with water. Cap and invert several times to mix thoroughly. A standard prepared in this fashion will cont
31、ain 20-g/mL nickel, 75-g/mL molybdenum and 150-g/mL aluminum, 20-g/mL phosphorous and is stable for one month. 5. Prepare a calibration blank at the same acid levels and with the internal standard added, but without any nickel, molybdenum , aluminum or phosphorous. Hydrofluoric acid is not required
32、for blank. Due to the linear response of the ICP instrument, multiple standards are not required. A single standard and calibration blank are sufficient to define the calibration line slope and intercept for each element. Table 1 Recommended Sample Dilution Concentration, mass-% Sample mass per 200
33、mL Al Ni Mo P Co 16-24 1 - 10 5 - 20 2 - 7 1 - 5 0.4 g 35-45 na na 7 - 25 na 0.2 g na= not applicable for this element Sample Preparation 1. Grind the sample to less than 80 mesh using UOP Method 918. 2. Mix the contents well, by hand for at least 30 seconds to avoid errors caused by stratification
34、due to settling of the ground sample in the bottle, then proceed immediately with Step 3. 3. Weigh, to the nearest 0.0001 g, the appropriate mass of ground catalyst into a 250-mL PTFE beaker (see Table 1). If the results are to be reported on a volatile-free basis, weigh a sample portion for LOI by
35、UOP Method 954 at the same time the sample is weighed for the metal determination. If the catalyst support is alumina only, a quartz beaker may be used. 4. Using a graduated cylinder, add 25 mL of water to the beaker to wet the catalyst. 5. Using a graduated cylinder, slowly add 10 mL of sulfuric ac
36、id to the beaker, and swirl to mix the contents. Add the acid slowly to avoid spattering. 6. If the catalyst support is silica-alumina, add 5 mL of concentrated hydrofluoric acid to the beaker, using a graduated polypropylene cylinder. Otherwise skip this step. Appropriate safety precautions must be
37、 taken when handling hydrofluoric acid. 7. Place the beaker on a hot plate and adjust the heat to achieve mild boiling. For alumina supports only, heat until the sample is completely dissolved, then proceed to Step 9. 8. Continue heating while slowly increasing the temperature until the evolution of
38、 thick white fumes, characteristic of sulfuric acid. Heating to sulfuric acid fumes eliminates all silicon as the tetrafluoride and any residual HF from the solution. DO NOT EXCESSIVELY FUME THE SAMPLES! Doing so will make it difficult to matrix match the standards with respect to acid level. 5 of 7
39、 925-16 When using PTFE beakers, do not exceed a hot plate temperature of 250C, as measured with a surface probe, or the beaker will deform and/or melt. 9. Remove the beaker from the hot plate, cool, and then carefully add approximately 40 mL of water to the beaker. Cover the beaker and return it to
40、 the hot plate. 10. Heat to a mild boil, and then remove the beaker from the hot plate and allow it to cool. 11. Using a funnel, transfer the contents of the beaker, quantitatively with water, into a 500-mL volumetric flask containing approximately 100 mL of water. 12. Allow the flask to cool to amb
41、ient temperature. 13. Pipet 10 mL of 100-g/mL scandium solution into the flask as an internal standard 14. Dilute to volume with water, and cap and invert the flask several times to mix thoroughly. 15. Using the sample dilution range, and the known composition of the catalyst, prepare the matched st
42、andard solution and a calibration blank in a manner similar to the example shown in Preparation of Calibration Standards. Sample Analysis Set up the ICP-OES instrument in accordance with the instrument manufacturers guidelines, allowing at least 30 minutes for equilibration after plasma ignition pri
43、or to starting the analysis. Table- 2 lists recommended wavelengths for the elemental determinations. Other wavelengths may be used if it can be shown that method precision is not adversely affected (see Precision). Use of a corrosion resistant sample introduction system is recommended. 1. Standardi
44、ze the instrument by aspirating the blank followed by the standard. Allow sufficient wash-out time between aspirations. 2. Aspirate the samples, after first entering the dilution factors into the computer. Allow sufficient wash-out time between aspirations. 3. Aspirate the standard, treating it as a
45、 sample with no dilution factor, as a calibration check. This should be done as often as recommended by the instrument manufacturer, but minimally after every 4-5 samples and after the final sample. Any calibration checks and the final standard reading should return the concentrations of the Ni, Mo,
46、 P, Co and/or Al in the standard within 3% relative. If not, recalibrate and reaspirate the samples. Table 2 Recommended Wavelengths Element Wavelength, nm Ni 231.604 Mo 204.597 P 214.913 Co 238.892 Al 396.152 Sc 424.683 Calculations If the dilution factor for the sample is entered into the instrume
47、nt computer, the concentrations of the elements in the original sample, on an as-received (AR) basis are calculated by the computer. Report the results to three significant figures. 6 of 7 925-16 If the LOI determination is completed prior to the instrumental analysis, the sample mass can be correct
48、ed to volatile-free, and that value entered into the instrument computer yields the elemental concentrations on a volatile-free basis. If the LOI determination is completed after the instrumental analysis, calculate the concentration of nickel, molybdenum, phosphorus, cobalt and/or aluminum in the o
49、riginal sample on a volatile-free (VF) basis using Equation 1: Element, mass-% =L100K100A(1) where: K = concentration of element in original sample, mass-% AR, from instrument printout L = LOI at 500C as determined by UOP Method 954, mass-% 100 = factor to calculate mass-% 100A = factor to convert to mass-% residue after ignition If desired, the elemental results can be reported as oxides. Multiply by the appropriate gravimetric factors listed in Table 3. Table 3 Gravimetric Factors To Convert Multiply By Ni to NiO 1.27254 Mo to MoO3
