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

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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

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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.

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C.c.

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50-100
50-100

17

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50-100

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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

Mg. +0.05 + .22

-.08 + .12 - .01 -.11

.11 + .27 +.07 +.07 -.03 -.03 -.08 + .22 + .22 +.12 + .75

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200

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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 litthu 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.

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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

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1

2

3

.062

5

6

.04

7

.038

8

. 05

9 10 11 12 13

.02

Per cent. Per cent. Per cent. Per cent. 38

0.054 0.045
40
.042

.035
41.5
none none

.052

none 45 .02

.017 46

.048 46 .046

none 46.5 .033

.027
47

.042
47
2.06

a.05
47
.024

none
48?
.048

.04
48
.02

.017
48

.019 48

.038 .032 48

.046 none 48. 5

.037 49.5 .054

.045

none 49.5

034

.028 50

.027
50.5

.033
50.5
.045

.038
51.5 . 10

. 083

none

.023

.055 .044

15 16 17 18 19 20 21 22 23 24

. 033

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Melilite-nepheline-basalt, Uvalde County, Tex.
Nephelinite, Uvalde County, Tex..
Saxonite, Douglas County, Oreg
Diorite, Cecil County, Md..
Gabbro, Adirondack region, N. Y
Plagioclase-basalt, Uvalde County, Tex
Amphibole-gabbro, Alpine County, Cal.
Plagioclase-gneiss, Amador County, Cal
Diorite, Mitchell County, N.C.
Porphyry, La Plata County, Colo.
Amphibolo-gabbro, Tuolumne County, Cal.
Orthoclase-bearing basalt, Uvalde County, Tex..
Orthoclase-bearing basalt, Uvalde County, Tex..
Norite, Cecil County, Md
Gabbro, Union County, Tenn..
Gabbro, Douglas Island, Alaska..
Nepheline-basanite, Colfax County, N. Mex
Olivine-basalt, Kruzof Island, Alaska..
Diabase, Mount Ascutney, Vt.....
Phonolite, Cripple Creek, Colo..
Syenite-lamprophyre, Prowers County, Colo....
Augite-andesite-porphyry, Electric Peak, Wyo.
Pyroxenic gneiss, Calaveras County, Cal....
Labradorite-porphyrite, Michigamme iron dis.

trict, Mich.
Pyroxenite, Cecil County, Md..
Orendite, Sweetwater County, Wyo.
Andesite, El Paso County, Colo..
Nepheline-syenite, El Paso County, Colo..
Diorite, Butte and Plumas counties, Cal.
Quartz-diorite, Cecil County, Md..
Diorite, La Plata County, Colo....
Camptonite? San Miguel County, Colo.
Phonolite, Colfax County, N. Mex...
Augito-bronzite-andesite, Unga Island, Alaska.
Andesito, El Paso County, Colo...
Spilosite, Michigamme iron district, Mich
Hornblende-granite, Cecil County, Md.
Latite, Tintic district, Utah
Monzonite, Tintic district, Utah....
Diorite-porphyry La Plata Mountains, Colo.....
Trachyte-andesite tuff, Tuolumne County, Cal...
Diorite, Douglas Island, Alaska
Rhyolite, San Miguel County, Colo.....
Syenite, Mount Ascutney, Vt...
Quartz-mica-diorite, Tuolumne County, Cal....
Quartz-monizonite, Calaveras County, Cal..
| Rhyolite, Tintic district, Utah
Quartz-diorite, Amador County, Cal
Trachyte, Highland County, Va....
Biotite-granite, Amador County, Cal
Rhyolite, Crater Lake, Oreg ..
Monzonite (altered), Tintic district, Utah.
Rhyolite (quartz-porphyry), Tintic district, Utah
Rock between rhyolite and dacite, Sutter County,

Cal
Syenite-porphyry, Mount Ascutney, Vt.
Granite-porphyry, Mount Ascntney, Vt
Granite, Union County, Tenn....

none

. 037 . 043 . 038

nope

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25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46

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52.5 53 54 54? 54.5 54.5 55 55.5 55.5 56 56.5 57 ? 58 58.5 60 60 60.5 62.5 63 64.5 65.5 65.5 67 69 69.5 69.5 70.5 71 71 71.5

.03 022 007 .024

none trace

.02

. 025 .018 .006 .02 .017 .014 a. 01

.003 trace?

.011

none

trace

.017 a.012

004 trace?

.013 .014 .009

005 trace? trace

004

trace trace

.012

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48 49 50 51 52 53 54

trace ft. tr.

. 021

. 003 .017 .013

none

.016

nono

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