ASTM C1271-99(R2020) pdf free download

ASTM C1271-99(R2020) pdf free download,Standard Test Method for X-ray Spectrometric Analysis of Lime and Limestone
6. Interferences
6.1 Interelement effects or matrix effects may exist for some of the elements listed. One way to compensate for these effects is to prepare a series of calibration curves to cover the designated concentration ranges. The composition ofthe speci- men being analyzed must match closely the composition of the reference materials used to prepare the calibration curve. Mathematical corrections, derived from empirical relationships or fundamental parameter calculations, may be used alterna- tively. Any ofthese are acceptable, providing that the analytical accuracy required by this test method is achieved. 6.2 Calcium is the primary component of the matrix ana- lyzed by this test method. The analyst must be aware of all possible interferences and matrix effects of this element. Orders ofall wavelengths may cause interference, for example, the effect of CaKβ1 (2nd order) on PKα1. 6.3 Contamination from the grinding apparatus is an ever- present source ofinterference ofwhich the analyst must always be cognizant. For example, stainless steel will impart iron, chrome, and nickel to the prepared sample. 6.4 Spectral interferences from the X-ray tube may also occur, for example, line overlap from CrKβ1 on MnKα1 caused by a chrome target tube.
7. Apparatus
7.1 Specimen Preparation Equipment: 7.1.1 Jaw Crusher, for initial crushing of lumps. 7.1.2 Plate Grinder or Pulverizer, with one static and one rotating disk for further grinding. 7.1.3 Rotary Disk Mill or Shatter Box, with hardened grinding containers and timer control for final grinding. 7.2 Briquetting Equipment: 7.2.1 Briquetting Press, capable of providing pressures up to 550 MPa (80 000 psi). The press shall be equipped with a mold assembly that provides a briquet compatible with the X-ray specimen holder. 7.3 Fusion Equipment: 7.3.1 Furnace or Gas Burners, with a timer, capable of heating the sample and flux to at least 1000 °C and homog- enizing the melt. 7.3.2 Fusion Crucibles: 7.3.2.1 Vitreous Carbon or Graphite, 20 to 30 mL capacity, with a flat bottom 30 to 35 mm in diameter. 7.3.2.2 Platinum/Gold, 95 % platinum/5 % gold alloy, 30 to 35 mL capacity. 7.3.2.3 Platinum/Gold Casting Dish, 95 % platinum/5 % gold alloy, 30 to 35 mL capacity, with a flat bottom 30 to 35 mm in diameter. 7.3.3 Polishing Wheel, suitable for polishing the fusion disk to obtain a uniform surface for irradiation. The analyst should be aware at all times of possible contamination from the polishing media used for surfacing the disk (6.3). 7.4 Excitation Source: 7.4.1 X-Ray Tube Power Supply, providing constant poten- tial or rectified power ofsufficient energy to produce secondary radiation of the specimen for the elements specified. The generator may be equipped with a line voltage regulator and current stabilizer. 7.4.2 X-Ray Tubes, with targets of various high-purity elements, capable of continuous operation at required poten- tials and currents, and that will excite the elements to be determined.7.5 Spectrometer, designed for X-ray emission analysis and equipped with specimen holders and a specimen chamber. The chamber may contain a specimen spinner, and it must be equipped for vacuum operation. 7.5.1 Analyzing Crystals—Flat or curved crystals with op- timized capability for diffraction ofthe wavelengths ofinterest. 7.5.2 Collimator, for limiting the characteristic X rays to a parallel bundle when flat crystals are used in the instrument. A collimator is not necessary for curved crystal optics. 7.5.3 Detectors, sealed or gas flow, proportional type, Gei- ger counters, scintillation counters or equivalent. 7.5.4 Vacuum System, providing for the determination of elements whose radiation is absorbed by air (atomic number below 20). The system shall consist of at least one vacuum pump, gage, and electrical controls to provide automatic pumpdown of the optical path and maintain a controlled pressure, usually 13 Pa or less. 7.6 Measuring System, consisting of electronic circuits ca- pable of counting or integrating pulses received from the detectors. The counts, count rate, or integrated voltages may be displayed on meters, recorders, digital counters, or voltmeters. The counts, count rates, or integrated voltages can also be presented to a computer or programmable calculator for conversion to percent concentration. Pulse height analyzers may be required to provide more accurate measurements for some measurements.