AS ISO 19976.1 pdf download

AS ISO 19976.1 pdf download.Copper, lead and zinc sulfide concentrates — Determination of cadmium
5  Reagents
During the analysis, use only reagents of recognized analytical grade and distilled water or water of equivalent purity. 5.1 Hydrochloric acid, concentrated (ρ 20 1,19 g/ml). 5.2 Hydrochloric acid, diluted 1+1. Slowly add 500 ml of concentrated hydrochloric acid (5.1) to 500 ml of water, while stirring. 5.3 Hydrochloric acid, diluted 1+9. Slowly add 50 ml of concentrated hydrochloric acid (5.1) to 450 ml of water, while stirring. 5.4 Nitric acid, concentrated (ρ 20 1,42 g/ml). 5.5 Hydrofluoric acid, concentrated (ρ 20 1,15 g/ml). 5.6 Perchloric acid, concentrated (ρ 20 1,70 g/ml). 5.7 Cadmium metal, minimum purity 99,99 %. 5.8 Cadmium, standard solution, 1 ml contains 1 mg of Cd. Weigh, to the nearest 0,1 mg, 1,000 0 g of cadmium metal (5.7) into a 250 ml beaker. Add 10 ml of water and 5 ml of nitric acid (5.4). Cover and warm gently (if necessary) until the cadmium metal is dissolved. Heat to remove nitrogen oxides, then allow to cool and add about 50 ml of water. Transfer the solution to a 1 000 ml one‑mark volumetric flask, add 40 ml of hydrochloric acid (5.2), fill up nearly to the mark with water, mix and cool to room temperature, then fill up exactly to the mark with water and mix again. 5.9 Cadmium, standard solution, 1 ml contains 100 μg of Cd. Pipette 10,00 ml of cadmium standard solution (5.8) into a 100 ml one‑mark volumetric flask. Add 20 ml of hydrochloric acid (5.2), fill up nearly to the mark with water, mix and cool to room temperature, then fill up exactly to the mark with water and mix again. 5.10 Cadmium, standard solution, 1 ml contains 10 μg of Cd. Pipette 10,00 ml of cadmium standard solution (5.9) into a 100 ml one‑mark volumetric flask. Add 18 ml of hydrochloric acid (5.2), fill up nearly to the mark with water, mix and cool to room temperature, then fill up exactly to the mark with water and mix again. 5.11 Cadmium calibration solutions. Prepare a series of calibration solutions by adding, from a pipette, 0,0 ml, 2,00 ml, 4,00 ml, 6,00 ml, 7,00 ml.These standards contain 0,0 µg, 0,2 µg, 0,4 µg, 0,6 µg, 0,7 µg, 0,8 µg, 0,9 µg and 1,0 µg of cadmium per ml and shall be freshly prepared. Calibration solutions should be prepared at the same ambient temperature as that at which the determinations will be conducted.
7  Samples
7.1  Laboratory sample Laboratory samples shall be taken and prepared in accordance with the procedures described in ISO 12743. 7.2  Test sample Prepare an air‑equilibrated test sample in accordance with ISO 9599. NOTE  A test sample is not required if pre‑dried test portions are to be used (see Annex A). 7.3  Test portion Taking multiple increments, extract approximately 0,50 g from the test sample and weigh to the nearest 0,1 mg. At the same time as test portions are being weighed for analysis, weigh test portions for the determination of hygroscopic moisture in accordance with ISO 9599. Alternatively, the method specified in Annex A can be used to prepare pre-dried test portions directly from the laboratory sample.
8  Procedure
8.1  Number of determinations Carry out the determinations at least in duplicate, as far as possible under repeatability conditions, on each test sample. NOTE  Repeatability conditions exist where mutually independent test results are obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment, within short intervals of time. 8.2  Blank test Carry out a blank test in parallel with the analysis using the same quantities of all reagents but omitting the test portion. The purpose of the blank test in this method is to check the quality of reagents. If a significant blank value is obtained as a result of the blank test, check all reagents and rectify the problem. 8.3  Determination 8.3.1  Dissolution of test portion Transfer the test portion into a 200 ml polytetrafluoroethylene beaker (6.2) and moisten with 5 ml of water. Add 10 ml of hydrochloric acid (5.1) and heat for 5 min at 60 °C to 70 °C. Add 10 ml of nitric acid (5.4) and heat gently. Add 3 ml of hydrofluoric acid (5.5), then heat gradually until the solution is about 5 ml at 60 °C to 70 °C. Add perchloric acid (5.6) repeatedly until the residue is not present. Heat until the strong white fumes have exhausted completely, then allow to cool. Add 40 ml of hydrochloric acid (5.2) [for lead concentrate samples, add 50 ml of hydrochloric acid (5.3)]. Wash down the cover and sides of the beaker and then heat until the onset of boiling, then allow to cool.