The Chemical Analysis of Argonne Premium Coal Samples
Edited by Curtis A. Palmer
1997
U.S. Geological Survey Bulletin 2144
Determination of 62 Elements in 8 Argonne Premium Coal Ash Samples by Automated Semiquantitative Direct-Current Arc Atomic Emission Spectrography
By Carol J. Skeen, B.J. Libby, and W.B. Crandell
Table 1. Photoplate preparation conditions
[Table modified from Dorzapf and others (1989, table 4). A, ampere; ASTM, American Society for Testing and Materials; dc, direct current; L, liter; min, minute; s, second; V, volt]
| Electrodes | Cathode: ASTM type C-6, 50 mm long. Anode: 6.3-mm diameter, thin-walled graphite (Ultra Carbon no. 3170). |
| Electrode charge | 15 mg sample + 30 mg graphite (type UCP-2, 200 mesh). |
| Spectrograph | 3.4-m Ebert (Jarrell-Ash Mark III). |
| Power source | 325 V, open circuit. |
| Excitation | 15-A dc arc, set with empty graphite electrodes. |
| Arc gap | 4 mm, maintained throughout arcing. |
| Exposure | 20 s at 5 A followed by 130 s at 15 A, continuous arcing. |
| Atmosphere | 70% Ar + 30% O 2 ; 6.6 L/min flow rate, with top of Helz jet nozzle 2 mm below top of electrode. |
| Wavelength range | 230.0-470.0 nm; first order. |
| Grating | 600 grooves/mm; 0.5 nm/mm reciprocal linear dispersion. |
| Slit | 25 m wide and 2 mm high. |
| Filter | 14% transmission neutral-density filter at slit. |
| Illumination | Arc image focused on collimator by 450-mm focal-length cylindrical quartz lens at slit. |
| Mask at collimator | 18 mm. |
| Emulsion | Eastman-Kodak III-0 (102 508 mm plates). |
| Processing | Eastman-Kodak D-19 developer, 3.25 min at 20C stirred by nitrogen bursts; Eastman-Kodak indicator stop bath, 30 s; Eastman-Kodak fixer, 10 min; wash, 20-30 min at 20C; Eastman-Kodak photo-flow, 1 min; and dry with warm air for 30 min. |
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