Slike strani
PDF
ePub

TABLE I.-- Test determinations of vanadium in presence of chromium.

[blocks in formation]
[ocr errors]
[blocks in formation]

Vanadium
pentoxide.

Vanadium
pentoxide
found.

Error.

Milligrams.

9.37
0.94

5. 25

5. 62

4.68

5. 62

Milligrams.

9. 22
1.04

.98
5. 49
5. 43
5.5
5.5
4. 78
4. 78
4.83
5. 58
5.58
18. 89
18.97
6.1
4. 78
5. 58
5.58
23. 81
23. 71
46. 98
47. 20
23. 65
23. 75
23. 71

Milligrams.

-0.15 +.10 + .04 + . 24 + . 19

. 12 - . 12 +.10 + .10 + .15 -.04

.04 + . 15 +.23 +.50 +.10 - .04

1.04 + . 29 + . 19 + . 13 + .35 + .13 +.23 + . 19

18. 74

5.6 4. 68 5. 62 5. 62 23. 52

46. 85

23.52

23.52

TABLE II.-Application of degree of correction for larger amounts of chromium, obtained

by adding potassium permanganate to an equal bulk of solution containing a like amount of chromic sulphate.

[blocks in formation]

c.c.

[blocks in formation]

Mg. +0.05 + .22

50-100
50-100

. 08

[blocks in formation]
[blocks in formation]
[blocks in formation]

a 100

Mgs.

1. 59 2. 69 2.39 2.59 19.4 19.3 19.3 2.99 2. 79 2. 79 2. 69 2.69 2. 69 2.89 2.89 2. 79 48. 60

Mgs.

0.99 2.09 1.79 1.99 18. 73 18.63 18.63 2.14 1.94 1.94 1.84 1.84 1. 79 2.09 2.09 1.89 47.60

+ .27 +.07 +.07 - .03 - .03 -.08 + .22 + .22 +.12 + . 75

[blocks in formation]

200

[blocks in formation]

200

a About.

In spite of the fact that the correction in most of the trials of this last table represents a large proportion of the permanganate used, the results must be considered satisfactory in view of the small amount of vanadium present, and they show that the method in competent hands after a little experience affords trustworthy figures.

TESTING THE METHOD ON ROCKS AND ORES.

The following table shows its availability for rocks and ores. Known amounts of both chromium and vanadium were added to an iron ore and to a silicate, both free from arsenic, which were then fused with sodium carbonate and nitrate and further treated as follows: After extracting with water and reducing manganese by alcohol, the silica and alumina were mostly removed by nearly neutralizing with nitric acid and evaporating to near dryness. The washed precipitate was ignited and treated with hydrofluoric and sulphuric acids, the residue fused with sodium carbonate, since it frequently contains a little chromium, and again nearly neutralized, etc. To the combined and slightly alkaline filtrates was added mercurous nitrate, the precipitate of phosphate, vanadate, chromate, and carbonate was ignited in platinum, fused with a little sodium carbonate, leached with water, and filtered into a small graduated flask. After colorimetric determination of the chromium, sulphuric acid was added, both chromium and vanadium were reduced by sulphur dioxide gas, and the titration carried out as described.

TABLE III.—Test determinations of vanadium added to rocks and ores in presence of

chromium.

[blocks in formation]

These and other experiments show that by taking not over 5 grams of ore or rock, vanadium, if present to the extent of 0.01 or 0.02 per cent, can be readily estimated by exercising reasonable care in all the operations. Absolute confirmation of its presence can be easily obtained by evaporating and igniting the solution to remove excess of sulphuric acid, taking up with a few drops of dilute nitric acid, and adding to the solution in a test tube a drop or two of hydrogen peroxide. In this way positive or negative assurance as to the presence of vanadium is given when the result of titration alone might be uncertain. Addition of ether at the same time affords a simultaneous test for chromium by its blue color, and this might, perhaps, be made use of, if necessary, to remove all or the greater part of the chromium prior to titration of the vanadium, since the oxidation product of the latter does not dissolve in the ether.

It is even possible that the dark brown color produced by hydrogen peroxide might be utilized for an exact colorimetric method for estimating vanadium.

DISTRIBUTION AND QUANTITATIVE OCCURRENCE OF VANADIUM AND MOLYBDENUM

IN ROCKS OF THE UNITED STATES.

By W. F. HILLEBRAND.

Aside from its well-known mineral combinations, vanadium has long been known to occur in magnetites and other iron ores. Hayes in 1875 reported its occurrence in a great variety of rocks and ores. Quoting from Thorpe's Dictionary of Chemistry: “It is said to be diffused with titanium through all primitive granite rocks (Dieulafait) and has been found by Deville in bauxite, rutile, and many other minerals, and by Bechi and others in the ashes of plants and in argillaceous limestones, schists, and sands

." It is further reported to comprise as V,03 0.02–0,07 per cent of many French clays, 0.02–0.03 per cent of some basalts, 0.24 per cent of a coal of unknown origin and 0.45 per cent of one from Peru, amounting to 38.5 per cent and 38 per cent of the ash, and noted respectively by Mourlot and Torrico y Meca. Doubtless many other instances of its occurrence have been noted.

In Table I following is shown its quantitative occurrence and distribution in a large number and variety of igneous rocks of the United States arranged according to their silica contents; and in Table II the same data are given for a few of the component minerals separated from some of these rocks, while Table III shows its presence in metamorphosed and secondary rocks by a few examples of roofing slates and schists and especially by two composite samples representing 253 sand. stone and 498 building limestones. These last two afford positive proof of its general distribution through rocks of those classes. Incidentally some information has been acquired as to molybdenum. Owing to lack of entire certainty as to its condition of oxidation, the vanadium is tabulated in terms of both V,03 and V,03, a point which will be reverted to later on. With very few exceptions the amount of each sample taken for analysis was 5 grams. The reagents used were carefully tested and found free from vanadium and molybdenum. Except Nos. 38, 39, 47, 52, and 53, by Dr. H. N. Stokes, all determinations are by myself. Bull. 167—4

49

[ocr errors][merged small][merged small][merged small][merged small][merged small][merged small]

1

. 035

2 3

none

. 062

4 5 6

.048

.04 .038

.027

a.05

.02

none

. 048

.023

7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

.055

.032 .046 .037

. 034 .033

.027 .033

none

.04

Per cent. Per cent. Per cent. Per cent. Melilite-nepbeline-babalt, Uvalde County, Tex. 38

0.054 0.045 Nephelinite, Uvalde County, Tex...

40

042 Saxonite, Douglas County, Oreg

41.5 none Diorite, Cecil County, MA

.052

none Gabbro, Adirondack region, N. Y

45

02

.017 Plagioclase-basalt, Uvalde County, Tex

46
Amphibole-gabbro, Alpine County, Cal..

46
046

nono Plagioclase-gneiss, Amador County, Cal

46.5 033
Diorite, Mitchell County, N.C

47
05

042
Porphyry, La Plata County, Colo...

47

a. 06 Amphibolo-gabbro, Tuolumne County, Cal..

47

.024 Orthoclase-bearing basalt, Uvalde County, Tex.. 48?

.04 Orthoclase-bearing basalt, Uvalde County, Tex.. 48

.02

.017 Norite, Cecil County, Md.

48

.019 Gabbro, Union County, Tenn..

48

.038 Gabbro, Douglas Island, Alaska..

48

none Nepheline-basanite, Colfax County, N. Mex

48.5

. 044
Olivine-basalt, Kruzof Island, Alaska..

49.5
. 054
.045

nono Diabase, Mount Ascutney, Vt...

49.5

..028
Phonolite, Cripple Creek, Colo

50
Syenite-lamprophyre, Prowers County, Colo.... 50.5 .04
Augite-andesite-porphyry, Electric Peak, Wyo. 50.5

045 .038
Pyroxenic gneiss, Calaveras County, Cal..

51.5 .10

. 083
Labradorite-porphyrite, Michigamme iron dig.
trict, Mich.

52.5

.048
Pyroxenite, Cecil County, Ma..

53
.04
.034

none Orondite, Sweetwater County, Wyo..

54

022

.018
Andesite, El Paso County, Colo...

54 ?
.018

.015 trace? Nepheline-syenite, El Paso County, Colo....

54.5

.018 trace ? Diorite, Butte and Plumas counties, Cal.

54.5

.031 none Quartz-diorite, Cecil County, Md.

55

none Diorite, La Plata County, Colo...

55.5

038 Camptonite? San Miguel County, Colo..

55.5 (6) (6) Phonolite, Colfax County, N. Mex..

56

trace trace Augite-bronzite-andesite, Unga Island, Alaska. 56.5

none Apdesite, El Paso County, Colo......

57 ?

.021 trace ? Spilosite, Michigamme iron district, Mich

58

.025

none Hornblende-granite, Cecil County, Md..

58.5
.022 .018

none Latite, Tintic district, Utah

60

pone Monzonite, Tintic district, Utah...

60

024

.02 trace Diorite-porphyry La Plata Mountains, Colo.... 60.5 Trachyte-andesite tuff, Tuolumne County, Cal.. 62.5

.014
Diorite, Douglas Island, Alaska

63
a. 012
a.01

none Rhyolite, San Miguel County, Colo....

64.5 004 .003 trace Syenite, Mount Ascutney, Vt..

65.5 trace? trace? Quartz-mica-diorite, Tuolumne County, Cal.. 65.5

.013

trace Quartz-monzonite, Calaveras County, Cal.

67

trace Rhyolite, Tintic district, Utah.

69

.008

none Quartz-diorite, Amador County, Cal

69.5 005 .004 trace Trachyte, Highland County, Va...

69.5 trace 1 trace? Biotite-granite, Amador County, Cal

70.5 trace trace trace Rhyolite, Crater Lake, Oreg.

71
004

003 ft. tr. Monzonite (altered), Tintic district, Utah

71

none Rhyolite (quartz-porphyry), Tintic district, Utah 71.5

016

nono Rock between rhyolite and dacite, Sutter County, Cal

71.5 trace trace Syenite-porphyry, Mount Ascutney, Vt.

73

[blocks in formation]

none Granite-porphyry, Mount Ascutney, Vt

73. 5 none Granite, Union County, Tenn....

76.5 none none

Done

none

a Approximate.

Lost, but considerable.

« PrejšnjaNaprej »