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THE ELEMENTS OF BLOWPIPE ANALYSIS
[Illustration]
THE
ELEMENTS OF BLOWPIPE
ANALYSIS
BY
FREDERICK HUTTON GETMAN, F.C.S.
INSTRUCTOR IN CHEMISTRY IN THE STAMFORD HIGH SCHOOL
New York
THE MACMILLAN COMPANY
LONDON: MACMILLAN & CO., LTD.
1899
_All rights reserved_
COPYRIGHT, 1899,
BY THE MACMILLAN COMPANY.
Norwood Press
J. S. Cushing & Co.--Berwick & Smith
Norwood Mass. U.S.A.
Transcriber's note: A word surrounded by underscores like _this_
signifies the word is italics in the text. A word surrounded by cedillas
like ~this~, signifies the word is bolded in the text. For numbers and
equations, underscores before bracketed numbers in equations denote a
subscript.
PREFACE
These few pages are intended to serve a twofold purpose,--to give the
student a general outline of Blowpipe Analysis, and to introduce him to
the methods of Determinative Mineralogy.
Every effort has been made to simplify details so that the book may be
used in both High Schools and Colleges.
Tables for "systematic" examination have been intentionally omitted, for
in the author's estimation these tend to dull the student's power of
observation, and to make him place little value upon minute details.
The alphabetic arrangement has been followed for the sake of convenience
when referring to the book.
The last chapter is not intended to serve as a key to determining the
minerals therein described, but rather it is added to give the student
exercise in Blowpipe Analysis, and at the same time to point out the
_methods_ of Determinative Mineralogy.
Finally, the author would acknowledge his indebtedness to the following
works: "Manual of Qualitative Analysis," Fresenius; "Qualitative
Chemical Analysis," Venable; Roscoe and Schorlemmer's "Treatise on
Chemistry"; Foye's "Hand-Book of Mineralogy"; Dana's "Mineralogy";
Kobell's "Tafeln zur Bestimmung der Mineralien"; etc.
FREDERICK HUTTON GETMAN.
STAMFORD, CONN.,
Feb. 22, 1899.
TABLE OF CONTENTS
CHAPTER I
PAGE
Apparatus and Reagents 1-7
CHAPTER II
General Outline of Blowpipe Analysis 8
Definitions 9
Examination on Charcoal Alone 10
Examination on Charcoal with Sodium Carbonate 13
Examination in Tube with Sodium Carbonate and Charcoal 15
Examination on Platinum Wire 16
Examination in Borax Bead 17
Examination with Cobalt Nitrate 20
CHAPTER III
General Reactions for the Detection of the Metallic
Elements in Simple Compounds 22
Aluminum 23
Antimony 24
Arsenic 25
Bismuth 25
Cadmium 26
Chromium 26
Cobalt 27
Copper 28
Iron 28
Lead 29
Manganese 30
Mercury 30
Nickel 31
Silver 32
Tin 32
Zinc 33
The Alkali Metals 34
Ammonium 34
Potassium 35
Sodium 35
Lithium 36
The Alkaline Earths 36
Barium 36
Calcium 37
Strontium 37
The Acid Elements 37
Borates 37
Bromides 38
Chlorides 38
Fluorides 38
Iodides 39
Nitrates 39
Phosphates 40
Silicates 40
Sulphides 41
CHAPTER IV
Behavior of Some of the Principal Ores before the Blowpipe 43
Ores of Antimony 46
Ores of Arsenic 47
Ores of Bismuth 48
Ores of Chromium 49
Ores of Cobalt 50
Ores of Copper 52
Ores of Iron 57
Ores of Lead 60
Ores of Manganese 63
Ores of Mercury 64
Ores of Nickel 65
Ores of Silver 66
Ores of Tin 69
Ores of Zinc 70
COMPARATIVE TABLES
I. Colors of Coatings on Charcoal 73
II. Flame Colorations 73
III. Colors of Borax Beads in oxidizing Flame 74
IV. Colors of Borax Beads in reducing Flame 75
V. Colors of Microcosmic Salt Beads in oxidizing Flame 76
VI. Colors of Microcosmic Salt Beads in reducing Flame 77
[Illustration: THE BLOWPIPE Fig. 1]
[Illustration: BUNSEN BURNER Fig. 2]
[Illustration: CHARCOAL BORERS Fig. 3]
[Illustration: AGATE MORTAR & PESTLE Fig. 4]
[Illustration: FORCEPS Fig. 5]
[Illustration: HAMMER Fig. 6]
[Illustration: 3-CORNERED FILES Fig. 7]
BLOWPIPE ANALYSIS
CHAPTER I
The blowpipe was first applied to mineral analysis in 1733 by Anton
Swab, and its applications have since been improved and extended by
various chemists, among whom may be mentioned Bergmann, Cronstedt, Gahn,
Berzelius, and Plattner.
~Blowpipe.~--The common blowpipe of the jeweller is not particularly well
suited to the operations of blowpipe analysis, since the flame has often
to be kept playing upon the assay for some time, and the condensed
moisture of the breath would seriously interfere with the passage of
the air through the jet. One of the best and least expensive forms of
blowpipe is shown in Fig. 1. This consists, as is seen from the
illustration, of a conical-shaped tube of tin closed at the wide end and
formed into a mouthpiece at the small end; soldered into the tube at the
large end, and at right angles to its axis, is a small brass tube which
terminates in a conical tip pierced with a very fine hole. With this
pipe it is possible to perform all of the operations of mineral
analysis.
Some little practice is necessary to keep the flame steady and to take
the breath at the same time.
No rule can well be given to the beginner, but his experience becomes
his best guide.
~Bunsen Flame.~--Any kind of flame can be used for the blowpipe, provided
it be not too small; but since almost every laboratory to-day is
furnished with gas and the Bunsen burner (Fig. 2), it will only be
necessary to describe the use of the flame from this source. Upon
examining the Bunsen flame with care, it will be seen that the flame
consists of three distinct parts.
A dark inner cone which consists of gas not yet raised to the ignition
point. Beyond this there is a luminous cone, where combustion is
incomplete owing to lack of oxygen, and outside of this we find the
non-luminous cone where the gas is completely burned.
This outer envelope is the hottest portion of the flame, and is known as
the "oxidizing" flame because there is an excess of oxygen which is
imparted to substances placed therein.
The luminous cone is known as the "reducing" flame, for in it metallic
oxides are reduced, the oxygen being taken up by the small incandescent
particles of carbon.
If the air-holes at the base of the Bunsen burner be opened, the two
inner cones become elongated, and the flame appears almost colorless.
The blowpipe enables us to get an oxidizing and a reducing flame of
better form and greater power. To do this we cut off the air supply at
the base of the burner and turn off the gas until the flame is about 1
cm. high; then upon introducing the blowpipe, and blowing a strong
continuous jet of air across the Bunsen flame, we produce an oxidizing
flame about 4-5 cm. in length. If the tip of the blowpipe be held
outside of the Bunsen flame, and the pressure of the stream of air be
diminished, we obtain a reducing flame.
~Supports.~--For supports, charcoal, platinum, and glass are chiefly used.
The charcoal should be made from some light wood, such as alder. It
should be well burnt, and should not scintillate or smoke.
The platinum supports are generally in the form of wire and foil.
Platinum-tipped forceps are frequently employed in blowpipe analysis.
Glass is used in the form of tubing.
Hard glass tubing, 3 mm. bore, is drawn off into ignition tubes 7-8 cm.
in length. Several dozen of these tubes should be made before commencing
the tests of the next chapter.
~Apparatus.~--A small agate mortar, 4-5 cm. in diameter, should be
provided in which to grind the samples to be examined.
The pestle, which should also be of agate, must be adapted to the
mortar in shape and size.
Two pairs of forceps will also be needed.
One pair should be of steel, and the other pair of brass, with fine
points.
Of other apparatus, the most necessary is:--
A small hammer and anvil.
Two three-cornered files.
Small piece of cobalt glass, about 5 x 10 cm.
Pocket magnifying lens.
Several small watch glasses--for metallic beads, etc.
~Chemicals.~--A list of the principal chemicals is here given:--
Sodium carbonate, Na_{2}CO_{3}.
Borax, Na_{2}B_{4}O_{7} + 10 H_{2}O.
Microcosmic salt, (HNaNH_{4}), PO_{4} + 8 H_{2}O.
Cobalt nitrate, Co(NO_{3})_{2} + 5 H_{2}O.
Potassium cyanide, KCN.
Hydrochloric acid, (dilute), HCl + nH_{2}O.
Litmus paper, red and blue.
Brazil-wood paper.
Any other special reagents which may be needed will be mentioned as
required.