ch hg Development of the Chemical Avis.

67
strong irritating smell is also a drawback in using this
element for analytical researches. I propose to replace
the bromine in this case by sedium hypochlorite, which,
in solutions of manganous salts in the presence of an
alkali, throws down the manganese in the form of hydrated
manganese dioxide by the following equation :—
MnCl, + NaOCl +2NaHO = (MnO, + H,0) + 3NaCl.
The sodium hypochlorite may be easily prepared and is
cheap.
Obouchoff Steel Works, St. Petersburg,

THE CHEMICAL NEWS.

Vor, XXXV, No. 8go.

QUANTITATIVE ANALYSIS OF CERTAIN
METALS IN IRON AND STEEL.
By SERGIUS KERN, St. Petersburg.

A Rent id

In several specimens of analysed hard steels from 0'3 to
o's per cent of tungsten was deteed. The specimens
in hand were received from Sweden as steel for instruments,
 especially for files. In analysing this steel for
tungsten it was found very troublesome to evaporate to
dryness the ammoniacal solution of tungstic acid, as the
boiling liquor is very often thrown out from the beaker.
The following alteration in this process was found to be
very practical :— . . .
5 grms. of the specimen are dissolved in aqua regia, and
the solution is evaporated to dryness, and then dissolved
in a mixture of 25 c.c. of water and 15 c.c. of hydrochloric
acid. The resuliing precipitate contains silica and
tungstic trioxide (WOj) ; it is next filtered from the solution,
 washed first by water acidulated by 5 per cent of
hydrochloric acid, and finally by pure alcohol.” The tungstic
trioxide is dissolved on the filter in strong ammonia ; the
filtrate is boiled for twenty minutes with 5 grms. of caustic
lime or caustic potash; hydrochloric acid is next added, the
solution is heated for some time, and the remaining precipitate
 of pure tungstic trioxide is filtered from the liquor,
dried on the filter, carefully ignited, and weighed, WO;
contains 79'31 per cent of tungsten. :
Having made several new experiments with chiomeisen
prepaied by the process described in my article in the
CuEmicaL NEWS (vol. xxxii., p. 136), I may strongly recommend
 the use of it in steel manufacture instead of
spiegeleisen and ferro-manganese. The resulting steel
is very soft and is far superior to the steels now in use for
the preparation of boiler plates, tyres, guns, wire, &¢. In
preparing such cast-steel in every crucible, containing
ordinarily 70 to 80 lbs. of raw material, 0°75 to 1°60 per cent
of chromeisen containing 50 to 60 per cent of metallic
chromium is added. In analysing the resulting chromeiron
 alloys the following process may be used. The work
ts quickly executed :—
From the solution containing iron and chromium, these
metals are precipitated by ammonium sulphide
[(NH,)28] ; the resulting precipitate is filtered from the
liquor, dried, and ignited for 30 to 40 minutes in a platinum
crucible with 4 parts of a mixture of equal quantities of
KNO; and K,CO3. The ignited and fused mass is placed
in a glass, and hot water with 5 per cent of alcohol is
next added. The liquor is boiled and filtered from the
precipitate ; the solution contains only the chromium salt,
which is precipitated by adding an excess of ammonia in
the form of chromium hydrate (Cr206He), which isstrongly
ignited ; the resulting chromium oxide (Cr203) is weighed
and the percentage is calculated knowing that this compound
 contains 322 per cent of chromium. In analysing
iron and steel the manganese is usually separated” from
the iron by sodium acetate, which throws down the iron
and leaves the manganese in solution, which is precipitated
 either by ammonium sulphide in the torm of manganese
 sulphide, or by bromine in the form of hydrated
manganese dioxide (3Mn0,-+ H0), which is next ignited,
and the resulting manganese compound, manganomanganic
 oxide (Mn30,), is weighed. The first process
of precipitation of manganese by (NH,),S is, however, a
dirty operation, giving at the same time not such correq
results as the bromine process. But as bromine is expensive
 the use of it in laboratories is limited. The

REPORT
ON THE
DEVELOPMENT 'OF THE CHEMICAL ARTS
DURING THE LAST TEN YEARS.*
By Dr. A W, HOFMANN.
(Continued from p. 50,}

Manufacture of Sulphuric Acid. By ROBERT HaSEN.
CLEVER, Manager of the Stolberg Works.
[r the slope of the ground permits no other arrangement
the waggons may have a low shape, and the tram-way
may be on the same level as the floor of the furnace. At
the Rhenania and in other places where the pyrites can be
brought up on to the kilns without difficulty, the charge
of lump-ore is introduced through an aperture in the vault,
and the process does not take more than 20 seconds, If
it is too difficult to convey the ore upon the top of the
kilns it is thrown in with shovels through the working
door. In this manner 400 kilos. can be introdaced in five
minutes. As charging always disturbs the progress of the
furnace it is advisable to restric it to a minimum of time,
Poor lump-ores are roasted in Freiburg and Oker in
small shaft furnaces with a lateral exit for the gases, and
a low vault in which a high layer of ore js constantly
maintained.
As for the roasting of smalls and rough fragments it is
sometimes carried on along with the lump-ores. This
method is not advantageous, and renders the burning of
the whole of the pyrites imperfect.
It is better to work up the smalls into balls (Klitten,
Stdckeln, Boulets).
For this purpose they are mixed with more or less clay
and water, and moulded into balls Or cut in pieces. The
dried balls are then burnt either alone, or mixed with
'ump-ores in the kilns described above, English establish.
ments which burn Spanish cupriferons pyrites mix the
inely ground ore with water without clay, and mould the
paste into balls, which hold together owing to tie presence
 of vitriol.
For roasting smalls and coarse powder several kilns
bave been latterly proposed.
In 1862 the so-called shooting-kilns were introduced at
Freiberg, their original and ingenious constru®ion being
due to Moritz Gerstenhéfer., They have been described
in most technological journals, and in Schwarzenberg’s
“Treatise on the Manufadure of Sulphuric Acid (p, 415),
they are represented in figures drawn to scale. F. Bode,
assistant in Gerstenhifer's technical office, describes them
in detail in his pamphlet * Contributions to the Theory
and Practice of the Manufacture of Sulphuric Acid.”}
He deals at length with all the objections to Gerstenhdfer’s
 furnaces, and endeavours to refute them,
The ores to be burnt in Gerstenhdfer’s kilns must first
be ground to a fine powder. They are desulphurised
whilst falling down a shaft of about 5 metres high, 1-25
metres wide, and 0'8 metre deep. This shaft is fitted up
with three-sided prisms of fire-clay, arranged with ope
* “Berichte ither die Entwickelung der Chemischen Industy'e
WNihrend ces Letzten Jahrzehends.”
t Compare Graham-Otto's Lelirbuch, Band 2, abth, I, 549.
_% “ Beitrage zur Theorie und Praxis der Sehwelel Shura Fabr.ia-Hon."