I R O N IN M A G N E T I T E O R E .
797
acidity of the two solutions with the volume of the solution rechlorinated will show the amount of hydrochloric acid needed. LABORATORY OF THE PHILADELPHIA AND
READING
RAILWAY COMPANY.READISG, P A . , September 13, 1900.
DETERMINATION OF IRON IN IlAGNETlTE ORE BY THE SPECIFIC GRAVITY TEST.’ B Y JOSEPH W. RICHARDS. Received October 21, rw.
M
ANY magnetite ores are simply mixtures of magnetite and quartz. T h e dressing of such ores at the mines up to a salable percentage of iron is often an important matter, and in such cases the weight of the ore, as determined by its I ‘ feel,” is the determining factor as to whether it should pass into the ore pile or to the dump. Every new streak of ore opened up brings new material to be thus classified. For such classification, the specific gravity of the ore, carefully taken on a good pair of scales, is of quite sufficient accuracy to answer all practical purposes. Indeed, in many cases, considering the difficulty of obtaining a small representative sample from a mixed lot of ore such as the chemist requires, the specific gravity test made on a considerable weight of sample pieces may be quite a s satisfactory as an analysis. T h e various ways in which specific gravity may be practically determined on an ordinary good scale need not be discussed here ; anywhere from I to 50 pounds of ore may be tested, according to the scale at hand, and the accuracy desired, and results usually obtained accurate to 0 . I O in any case, and often to 0 . 0 2 or 0.03, in the specific gravity. Such variations would mean a variation of I to 3 per cent. on the iron content, according to the richness of the ore. With ores over 45 per cent. of iron, the variation or error need not be over 2 per cent. on the iron, in any case. To facilitate such tests, I have calculated the following table of the specific gravity of mixtures of magnetite and silica, of specific gravity of 5.18, and 2.66 respectively, for every I per cent. of iron contained, giving in each case also the percentages of magnetite and quartz in the mixture, the latter datum being of particular importance in valuing the ore. 1 Read at the October meeting of the Lehigh Valley Section of the American Chemical Society.
RANDOLPH BOLLIKG.
798
Fe. Fe,Oa. SiO,. Per cent. Per cent. Per cent 0
0.0
I
1.4 2.8 4.1 5.5 6.9 8.3 9.7
2
3
4 5 6 7 8 9
100.0
98.6 97.2 95.9 94.5 93.1 91.7 90.3 89.0 87.6 86.2 84,s 83 4 82.0 80.7 79.3 77.9 76.5 75.2 73.8 72.4 71.0 69.6 68.2 66.8 65.5 64.1 62.7 61.3 60.0 58.5 57.2 55.8 54.4 53.0 51.7 50.3
11.0
12.4
13.8 15.2 16.6 18.0 19.3
IO I1
I2
'3 I4 '5 16 I7 IS '9
20. j 22. I
23.5 25.8 26.2 27.6 29.0 30.4 31.8 33.2 34.5 35.9 37.3 38.7 40.0 41 .4 42.8 44.2 45.6 47.0 48.3 49.7
20
21 22
23 24 25 26 27 28 29 30 31 32 33 34 35 36
Specific Fe. giavity Per cent
2.66 2.67 2.69
*-
51
38 39
FelO,. Per cent. 51.0
2.71
40
2 $73
41
32.4 53.8 55,2 56.6
2.75 2.77 2.79 2.81 2.83 2.85 2.87 2.89 2.92 2.94 2.96 2.98 3.00 3.03 3.05 3.07 3.09 3.12 3. I4 3.17 3.20 3.22 3.25 3.27 3.30 3.33 3.36 3.39 3.42 3.45 3.48 3.51
42
$3.0
43 44 45 46 47 48 49 50 51 52 53 54
59.4 60.8 62. I 63.5 64.9 66.3 67.7 69.1 70.5 71.8 73.2
55 56 57 5s 59 60 61 62 63 64 65 66 67 68 69 70 72
76.o 77.4 78.8 so. I 81.5 82.9 84.2 85.6 87.0 88.4 89.8 91.2 92.6 94.0 95.3 96.7 98.0 99.4
72.4
100.0
74.6
71
SOp. Per cent.
Specific gravity.
49.0 47.6 46.2 44.8 43.4 42 .o 40.6 39.2 37.9 36.5 35.1 33.7 32.3 30.9 29.5 28.2 26.8 25.4 24.0 22.6
364 3.57 3.60 3.64 3.67 3.70 3.74 3.77 3.81 3.85 3.89 3.93 3.97 4.01 4.05 4.09 4.13 4.17 4.22 4.26 4.31 4.36
21.2
19.9 18.5 17.1
15.8 14.4 13.0
11.6 10.2
9.8 7.4 6.0 4.7 3.4 2.0
0.6 0.0
4.41 4.46 4.51 4.56 4.61 4.66 1.72 4.78 4.84 5.90 4.96 5.02 5.09 5.16 5. I8
LEHIGH UNIVERSITY,
October 18, 1900.
IRREGULAR DISTRIBUTION OF SULPHUR IN PIG IRON. BY RANDOLPH BOLLING. Received October 8, 1900.
s
ULPHUR determinations sonietimes show marked differences when samples are drilled from different points on the same pig. M . J . Moore' has noticed the low results obtained from 1 This
Journal,
21,
972-975.
