1、INTERNATIONAL STANDARD IS0 7156 First edition 1991-03-01 Refined nickel - Sampling Nickel raffin6 - - drums containing metal pieces. The pieces may be cut cathodes (generally squares with 25 mm, 50 mm or 100 mm edges), briquettes, pellets, shot, granules or powder. The capacity of the drums is most
2、often 50 kg, 250 kg or 1000 kg. n The number of increments taken from each of the primary increments. N x n The number of secondary increments which constitute the secondary sample. NOTE 2 The justification of the number of primary and secondary increments is given in annex A. 4.2 Sample selection 4
3、.2.1 From the I/ units contained in the lot, N units are selected to constitute the primary sample. The selection of these units shall respect the rules of random sampling. 4.2.2 From each of the N primary increments, n secondary increments are taken. The (N x n) sec- ondary increments are combined
4、and constitute the secondary sample. 4.2.3 An adequate complementary treatment to re- duce the mass of the secondary sample results in the final laboratory sample for chemical analysis. Cathodes or briquettes are machined to obtain a final sample in the form of fine chips. Pellets, shot or granules
5、are either taken as they are or, when their particle size analysis allows, machined to ob- tain chips. Powders are homogenized and reduced by riffling until the final sample is obtained. 1 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo
6、 reproduction or networking permitted without license from IHS-,-,-IS0 7156:1991(E) 5 Sample preparation 6 Sampling of whole-sheet cathodes 5.1 The laboratory sample shall be prepared as directed in the clauses dealing with various product forms. 5.2 The laboratory sample shall be of sufficient mass
7、 for the chemical analysis planned. For fine chips or powder, it is recommended to divide a sample of at least 200 g between two parties and to keep two portions in reserve in case of dispute. For larger pieces, such as pellets, granules or shot, a minimum mass of 500 g is recommended for each party
8、 and for reserve. 5.3 Precautions in sample preparation 5.3.1 Given the high purity of certain qualities of nickel, extremely strict precautions shall be taken in order not to contaminate the sample. Contamination of a sample may occur from tools, utensils and con- tainers used in the sampling opera
9、tion. Care shall therefore be taken in their selection and use to eliminate or minimize such contamination. 5.3.2 Contamination from cutting tools by elements such as cobalt, chromium, molybdenum, vanadium and tungsten shall be avoided. All machining oper- ations shall be carried out without using l
10、ubricants. Experience has shown that high-speed steel cutting tools are better for nickel metal than tungsten carbide tools. 5.4 Final preparation of the laboratory sample 54.1 Any sample which has been through a me- chanical preparation and, in particular, machining into chips, will inevitably be c
11、ontaminated on the surface of the metal by, at least, the element iron. It is essential, therefore, that the chips or pieces are cleaned by etching with acid before the test sample is taken for analysis. Unless otherwise specified in the International Standard to be used for the ana- lytical method,
12、 the laboratory shall be instructed to clean the test sample as directed in 5.4.2. 5.4.2 Place the chips in a beaker and cover with a few millilitres of concentrated hydrochloric acid. Heat at low temperature and, as soon as dissolution starts (evolution of a few bubbles), add a large quantity of di
13、stilled or demineralized water to stop this dissolution, Pour off the diluted acid and wash the chips several times with water, by decantation of the water from the beaker, until acid-free. Wash the chips with high-purity acetone and dry them in a low-temperature oven. Take the test sample to be ana
14、lysed from the clean chips and keep the re- mainder for future analyses. 6.1 Primary sampling 6.1.1 Determine the number of units (1 of whole- sheet cathodes in the lot and select, at random, N units (primary increments) using table 1 as a guide. The number of units in a lot of a given mass and the
15、number of units which constitute the primary sample in table 1 are based on a unit mass of 50 kg. 6.1.2 If the mass per cathode is significantly differ- ent from 50 kg, the number of primary increments N shall be selected on the basis of the mass of the lot, as given in column 1 of table 1, and the
16、number N of selected units as given in column 3 of table 1. 6.2 Secondary sampling 6.2.1 From each of the primary increments, n sec- ondary increments as given in column 4 of table 1 shall be taken. Where values of IZ are coupled, e.g. 3 and 2, or 2 and 1, these are to be distributed ran- domly amon
17、g the N primary increments to give (N x n) as given in column 5 of table 1. 6.2.2 The secondary increments may be taken by any one of the three following methods. 4 b) c) Drilling a hole through the cathode using a drill, preferably with a diameter between 15 mm and 25 mm. It is possible to obtain c
18、hips by appro- priate shaping of the drill. Strands of metal shall be cut into small pieces. Milling a hole using a cylindrical milling cutter with a diameter between 15 mm and 25 mm to produce chips directly. It may be necessary to drill a small pilot hole, e.g. 2 mm to 3 mm, when using certain des
19、igns of cutter. Punching out a disc of about 15 mm to 25 mm diameter and milling the disc to produce chips. 6.2.3 For the position of the secondary increment, five geometrical positions are defined on a diagonal of a whole-sheet cathode. Position 1 is taken at a distance of 25 mm to 30 mm from one c
20、orner. The distance from position 1 to the centre of the cathode is then divided into five equal intervals to define positions 2 to 5. Thus position 5 is a little before the middle of the cathode. A template may be used to define the positions of the holes along the diagonal of the cathode. The star
21、ting corner for the template shall be alternated for each cathode to be sampled, to avoid bias due to starting at the top or bottom of the cathode. 2 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted w
22、ithout license from IHS-,-,-IS0 7156:1991 (E) 6.2.4 For lots of greater than 3,75 tonnes (where II= 1) the secondary increment from the first cath- ode shall be taken at position 1, from the second at position 2, etc., and back to position 1 for the sixth cathode. When n is greater than 1, the (N x
23、n) in- crements shall be distributed among the N cathodes so that positions 1 to 5 are used nearly the same number of times. 6.2.5 Combine th chips from the (N x n) in- crements constituting the secondary sample and mix thoroughly. The mass of the chips shall be at least 200 g. Divide the sample by
24、riffling or by frac- tional shovelling to provide the required number of laboratory samples. 7 Sampling of drums containing forms requiring comminution or machining Nickel forms such as cathode shapes, briquettes, shot or large granules or pellets require comminution or machining to obtain chips or
25、pieces of a suitable size for the laboratory sample. 7.1 Primary sampling 7.1.1 The number of units U in a lot is the number of drums of given mass. Select the number of drums N to constitute the primary sample as given in table 1 for drums of 50 kg, table2 for drums of 250 kg and table 3 for drums
26、of 1000 kg. 7.1.2 For drums of intermediate mass, the numbers N and n shall be adjusted such that the total number of secondary increments (N x n) is the constant number given in table 1 to table3 for a given tonnage. The number of units N shall be as high as possible as a function of the number of
27、units U in the lot, and n shall be as small as possible for a given value of (N x n) specified in table 1 to table 3. The following example illustrates this point: 5 tonne lot, by drums of 400 kg U = 13 drums From table 2, N x n = 23 and N = 20 but N cannot be greater than U Therefore n is 2 or 1 an
28、d N = 13 i.e. n = 2 for 10 of the drums and 1 for 3 of the drums. 7.2 Secondary sampling 7.2.1 From each drum constituting the primary sample, take at random one or more pieces (sec- ondary increments) as given in table 1 to table 3. 7.2.2 Machine the secondary increments by milling or drilling and
29、cutting, as indicated in 6.2.2, to obtain chips. Briquettes shall be machined from the edge to the centre such that one half of each piece is consumed in the milling process. Large pellets or shot may be pressed between platens for further machining or cutting. 7.2.3 Combine the chips from the (N x
30、n) in- crements constituting the secondary sample and mix thoroughly. The mass of the chips shall be at least 200 g. Divide the sample by riffling or by frac- tional shovelling to provide the required number of laboratory samples. NOTE 3 For pellet or shot, it may be necessary to in- crease the valu
31、e of n to obtain sufficient material for the laboratory samples. 8 Sampling of drums containing forms not requlrlng comminution or machining Nickel forms such as powder, fine shot and granules and small pellets can be sampled directly and do not need further preparation such as comminution. 8.1 Prlm
32、ary sampling 6.1.1 Select the number crements) to constitute the rected In 7.1.1. 8.2 Secondary sampling of units (primary in- primary sample as di- 8.2.1 One secondary increment of at least 500 g shall be taken from each drum constituting the pri- mary sample. The masses of each of these second- ar
33、y increments shall be approximately equal. For products which are known to be homogeneous, ma- terial may be scooped from the top of the drum. Otherwise, secondary increments shall be obtained by fractional shovelling or by riffling the whole drum. 8.2.2 Secondary increments of nickel powder produce
34、d by chemical methods shall be obtained by successive riffling of the entire contents of each drum through I:1 splitters until a mass of about 500 g is obtained from each of the primary in- crements. 8.2.3 Combine the (N x n) secondary increments constituting the secondary sample and homogenize. Red
35、uce the bulk of the sample by consecutive riffling through I:1 splitters to obtain the required number of laboratory samples. 3 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IH
36、S-,-,-IS0 7156:1991(E) 9 Sampling report The sampling report shall include the following par- ticulars: a) reference to the appropriate clauses of this In- ternational Standard; b) any operation not included in this International Standard or which is regarded as optional; c) any unusual features not
37、ed during sampling or any deviations made from the sampling pro- cedure. 4 Copyright International Organization for Standardization Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 7156:1991 (E) Mass of lot tonnes Table 1 -
38、Sample selection from units of 50 kg Nxn3) Total number of units In lot N ) n 2) 0,050 1 1 5 5 0,100 2 2 3 6 0,150 0,200 : : 3 and 2 7 2 8 0,250 5 5 2 and 1 9 0,300 to 0,400 6 to 8 6 2 and 1 9 0,450 to 0,550 9 to 11 7 2 and 1 IO 0,600 to 0,700 12to14 8 2 and 1 11 0,750 to 0,850 15to 17 9 2 and 1 11
39、0,900 to 1,050 18 to 21 10 2 and 1 12 1,100 to 1,300 22 to 26 11 2 and 1 13 1,350 to 1,500 27 to 30 12 2 and 1 14 1,550 to 1,750 31 to35 13 2 and 1 15 1,800 to 2,050 36 to 41 14 2 and 1 15 2,100 to 2,350 42 to 47 15 2 and 1 16 2,400 to 2,650 48 to 53 16 2 and 1 17 2,700 to 3,000 54to 60 17 2 and 1 1
40、8 3,050 to 3,350 61 to 67 18 2 and 1 19 3,400 to 3,750 68 to 75 19 2 and 1 20 3,800 to 4,150 76 to83 20 1 20 4,200 to 4,550 84to 91 21 1 21 4,600 to 4,950 92 to 99 22 1 22 5,000 to 5,450 loot0 109 23 23 5,500 to 5,900 110 to 118 24 1 24 5,950 to 6,400 119tol28 25 1 25 6,450 to 6,900 129 to 138 26 1
41、26 6,950 to 7,450 139 to 149 27 1 27 7,500 to 8,000 150to 160 28 1 28 8,050 to 8,550 161 to 171 29 1 29 8,600 to 9,150 172 to 183 30 1 30 9,200 to 9,750 184to 195 31 1 31 9,800 to 10,400 196 to 208 32 1 32 10,450 to 10,950 209 to 221 33 1 33 11,000 to 11,750 222 to 235 34 11,800 to 12,400 236to 248
42、35 1 34 35 12,450 to 13,150 249to 263 36 1 36 13,200 to 13,850 264to 277 37 1 37 13,900 to 14,600 278 to 292 38 1 38 14,650 to 15,400 293 to 308 39 1 39 15,450 to 16,150 309 to 323 1: 1 40 16,200 to 17,000 324to 340 1 41 17,050 to 17,800 341 to 356 42 1 42 17,850 to 18,650 357 to 373 43 1 43 18,700
43、to 19,550 374 to 391 44 1 44 19,600 to 20,400 392to408 45 1 45 20,450 to 21,350 409 to 427 46 1 46 21,400 to 22,250 428to445 47 1 47 22,300 to 23,200 446 to464 48 1 48 23,250 to 24,150 465to483 49 1 49 24,200 to 25,000 484 to 500 50 1 50 1) Nis the number of units sampled (primary increments). 2) n
44、is the minimum number of secondary increments from each of the N sampled units. 3) The pairs of values for n (e.g. 3 and 2) shall be distributed randomly over the N sampled units so as to obtain the number (N x n)of secondary increments indicated. Copyright International Organization for Standardiza
45、tion Provided by IHS under license with ISONot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IS0 7156:1991(E) Mass of lot tonnes Table 2 - Sample selection from units of 250 kg Total number of units in lot N ) n 2) Nxn3) 0,250 1 1 0,500 2 2 0,750 3 3 1,000 4 4 1,250
46、5 5 1,500 6 6 1,750 7 7 2,000 8 8 2,250 9 9 2,500 10 10 2,750 11 11 3,000 12 12 3,250 13 13 3,500 14 14 3,750 15 15 4,000 16 16 4,250 17 17 4,500 18 18 4,750 19 19 5,000 20 20 5,250 21 21 5,500 22 22 5,750 23 23 6,000 24 24 6,250 25 25 6,500 to 6,750 26 to 27 26 7,000 to 7,250 28 to 29 27 7,500 to 7
47、,750 30 to 31 28 8,000 to 8,250 32 to 33 29 8,500 to 9,000 34 to 36 30 9,250 to 9,500 37 to 38 31 9,750 to 10,250 39 to 41 32 10,500 to 10,750 42 to 43 33 11,000 to 11,500 44 to 46 34 11,750 to 12,250 47 to 49 35 12,500 to 12,750 50 to 51 36 13,000 to 13,500 52 to 54 37 13,750 to 14,250 55 to 57 38
48、14,500 to 15,000 50 to 60 39 15,250 to 15,750 61 to 63 40 16,000 to 16,750 64 to 67 41 17,000 to 17,500 68 to 70 42 17,750 to 18,250 71 to 73 43 18,500 to 19,250 74 to 77 44 19,500 to 20,000 78 to 80 45 20,250 to 21,000 81 to 84 46 21,250 to 22,000 85 to 88 47 22,250 to 22,750 89 to 91 48 23,000 to
49、23,750 92 to 95 49 24,0Q0 to 25,000 96 to 100 50 9 9 5 IO 4 and 3 11 3 12 3 and 2 12 3 and 2 13 2 14 2 and 1 15 2 and 1 16 2 and 1 16 2 and 1 17 2 and 1 18 2 and 1 19 2 and 1 19 2 and 1 20 2 and 1 21 2 and 1 22 2 and 1 22 2 and 1 23 2 and 1 23 2 and 1 24 2 and 1 24 2 and 1 25 2 and 1 25 2 and 1 26 2 and 1 27 1 27 1 28 1 29 1 30 1 31 1 32 1 33 1 34 1 35 1 36 1 37 1 38 39 f 40 1 41 1 42 1 43 1 44 1 45 1 46 1 47 1 48 1 49 1 50 1) N is the number of units sampled (primary increments). 2) n is the
