March 28, 1918.

THE COLLIERY GUARDIAN.

643

In all these things, in every direction, there was room
for investigation and improvement. It was obvious that
that investigation could not be done by any one person.
At the same time, it was obvious that any one
person might contribute to it, and he thought that the
fact that so much was still unknown showed that there
was a very great scope for the work of a chemist in
coke oven practice and that the chemist should be one
with as wide a training as possible. It was not simply
chemistry, in the narrow sense of the word, that was
needed ; there was a great deal of physics as well. The
wider a man’s knowledge, the wider his training in every
branch of physical science, the more likely he was to be
able to overcome difficulties that might present them-
selves and to initiate improvements in his processes.
Coal was our greatest national asset and an asset which
we should have to economise, in the true sense of the
term, as well as we could, by using it to the best
advantage. A man who had had a wide training and
then had to turn himself in some particular direction
would almost always have an advantage over the man
who had been trained only in that particular direction,
even although he might have been trained for a longer
period than the other man.

DISCUSSION.

The Chairman remarked that Dr. Dunn had told
them pretty well what was required of them and their
employers. Up to the present the majority of employers
had had boys who went through certain routine pro-
cesses and that had had to satisfy the works managers.
Investigation into the nature of coal would, he thought,
be outside the scope of the coke oven manager in the
majority of instances, but it would be within the scope
of the chemist to take the coal along, starting from any
fixed temperature, go up or down in the scale, separate
the different distillates and gases involved and examine
them carefully. That took tremendous time and
labour to carry through and would require a
very skilled man. Every degree of heat, rising
or falling, influenced both the coke and the by-
products. The treatment of coal by solvents might or
might not assist them. The solvents disintegrated the
constituent parts of the coal somewhat, but it was not in
disintegration that they wanted to find a thing out, but
in the coal as a whole. What Dr. Dunn had said as to
the wide experience of the chemist applied, also, to the
coke-oven manager; it did not do for the latter, either,
to get into a narrow groove, but he also must keep alert
and up to the times. He proposed a vote of thanks to
Dr. Dunn.

Mr. A. H. Middleton, seconding, said Dr. Dunn did
not need to emphasise to that meeting the necessity of
the employment of chemists of high standing, but the
necessity of such emphasis still existed so far as many
coal owner s were concerned. The latter needed to have it
impressed upon them that they would get a good return
for their money invested in chemists. He had no doubt,
however, that the leading coal owners in that and other
districts were very rapidly realising that necessity for
chemists. The outlook for well-trained chemists in the
industry was very much better—and it needed to be—
than in the past. It struck him that the manufacture
of ammonium nitrate was one of the developments that
might easily obtain in the near future. One wondered
that work on that point had not been done before with
a view to making ammonium nitrate at coke ovens; it
seemed so obvious. If anything could be done, he
concluded, to convert a Northumberland steam coal
into as good a coking coal as that of Durham, it would
revolutionise the coal industry of Northumberland.

The vote was cordially carried.

Replying to a member who asked if the change from
quartz into tridymite was permanent or merely
reversible, Dr. Dunn said it was practically permanent.
Tridymite could be converted into quartz, but it did not
naturally become converted. A good deal of enquiry
and investigation into the conduct of refractory
materials was going on all over the world. He himself
did a considerable amount of work ascertaining the
melting points of such materials. For the work, he had
a little furnace, provided with a blow-pipe and a
Fletcher’s oxygen blow-pipe for higher temperatures,
and used magnesia crucibles. Until recently, he had
had his fireclay furnace lined with magnesia, to prevent
the walls of the furnace melting. < Magnesia, however,
had the disadvantage of being a very good conductor of
heat. Recently he had procured some zirconia and
lined the furnace with that. Zirconia was not nearly as
efficient a heat conductor as was magnesia. The result
was that, by using it as a lining to the furnace, one got
a much higher temperature in the crucible with the
Bunsen burner than 'one used to, and the necessity to
use the oxygen blow-pipe was not nearly as great.
Asked whether we were really at a disadvantage as
compared with Germany because we had not got as
many chemists, and whether Germany’s success was not
due to her chemists being very narrow specialists,
Dr. Dunn said he had not had any practical experience
of chemists at German coke ovens. Germany had
chemists both as men specialising narrowly and as men
of wide culture. He thought that in Germany even the
former had had a good all-round training in the first
instance.

Mr. Allen (Redcar) said he thought the scheme that
his employers (Messrs. Dorman, Long and Company
Limited) were bringing into operation now was a very
good one. They were allowing each department to have
its own laboratory and staff of chemists, and were estab-
lishing a central laboratory, the duty of which would be
to test all the products and to assist in cases of difficulty
in any of the departments.

Dr. Dunn remarked that it was an admirable scheme.

Mr. J. Porteous said he believed that one of the
essentials of the success of a chemist was to get his firm
interested in the value of chemists. He did not think
that even nowadays, after all we had gone through in
connection with the war, the chemist was valued as he
ought to be. Just at the beginning of the war, he was
in conversation with a gentleman superintending certain
by-product works, who told him that he very much
questioned whether it was necessary to have a chemist

in connection with those works. Personally, the speaker
thought it would be a great assistance to the young
chemist if some of those of wider experience would
advise as to the books of use to young people studying
chemistry. In his younger days he wasted pounds in
the purchase of books that he need not have had. He
thought, too, that the owners should be approached and
acquainted with the value of a library at any by-product
works. If that were done, he was under the impression
that these libraries would probably be provided.

Dr. Dunn observed that books should be purchased
by the owners just as apparatus was, if needed in
connection with the works.

The meeting then closed.

RAPID DISCHARGE OF COAL CARGOES.

An apparatus that greatly facilitates the unloading of
bulk cargoes, such as ore or coal, is the Brownhoist
power scraper shovel. In unloading there is always a
certain amount of material that lies between the hatches
and cannot be reached by the grabs. The work of the
power scraper shovel is to place this material beneath
the hatch openings, thereby doing work that formerly
required hand shovellers. This shovel is able to keep
enough material beneath the hatch opening to cause
the unloading bucket to get a full load at each grab,
and deliver the material fast enough to keep the
unloading machines busy. It is easily seen that the
time of unloading the boat can thus be materially
reduced; and the unloading records, in comparison with
records of unloading by hand shovellers, show that the
time in unloading ore or coal boats has been reduced
from 5 to 25 per cent, by the use of the new device.

The power scraper shovel consists of a high-powered
gasoline engine operating a raisable bucket, located at
the front of the machine. When the bucket is raised
to its top limit it is in a dumping position and the load
falls out. The entire mechanism is mounted on two
rubber-tyred driving wheels, with a third wheel at the
rear as a trailer and. steering wheel. The two driving
wheels are connected to the engine by means of gearing
and clutches to cause the shovel to travel back and
forth. The hoisting drums for raising the bucket and
dumping it are also connected to the engine through
gearing and clutches. All the operations are controlled
by the operator by means of levers located in front of
his seat. Brakes are supplied so as to give the operator
full control of the operation.

There are two sizes of shovels. The lighter one,
weighing about 8,000 lb., for working in coal and like
materials, is a little over 11 ft. long and 5 ft. 2 in. wide.
The heavy shovel, weighing about 16,u00 lb., is used for
handling ore and other heavy materials. This shovel is
12 ft. 8 in. long and 6 ft. wide.

When working in the hold of a boat the shovel pushes
the material to the desired point instead of handling
it a bucketful at a time. This makes the operation
much faster, as more material is handled each trip.
When working in the bow, stern or against bulkheads,
it is necessary for the shovel to handle the material a
bucketful at a time, carrying the load to the hatch.
This can be quickly done, as was proved in unloading
one steamer. The shovel took out 100 tons from the
bow and delivered it to hatch No. 3 in 45 minutes, or
approximately two hours less time than was required
to do the same work with hand shovellers. On a certain
class of steamers some ore is carried beneath the
boilers. The shovel reaches this ore and handles it at
the rate of two tons per minute.

Time is saved if the shovel delivers the material from
the space under two or three hatches to one hatch,
which it can do fast enough to keep the unloading
bucket busy. By this method more material is moved
in a given time, as it thus provides a larger pile for the
unloading bucket to work in.

After the shovel pushes its way through a pile and an
opening has been made, the shovel then takes its load
off the edges, pushing it beneath the hatch and working
back and forth in this manner until the floor is clean.
The high speed of the machine enables it to clean up
such a pile in a few minutes.

The shovels are being used in the old boats as
well as in the later types. They cannot work in the
former to such good advantage as in the newer types;
nevertheless, they are a big labour and time saver, even
working under the disadvantages found in the older
type of boats. The shovel is handled in and out of
the boat by attaching it to the grab bucket hoisting
apparatus.

A boat is released from one to four hours sooner than
when hand shovellers were used, and it has been demon-
strated that the cost of 12 to 40 shovellers is saved,
depending on the type of boat.—Black Diamond.

Priestman Collieries New Product.—Mr. G. D. Cowan
exhibited a specimen of cuprous oxide to the recent meet-
ing of the Society of Chemical Industry (Newcastle
Section). Formerly, he said, the manufacture of this was
confined to Germany but, thanks to their chairman’s pluck
and determination, it was now being made by the
Priestman Collieries Limited, whose product was equal to
the best German product.

Timber Haulage.—The Secretary of the War Office
announces that arrangements have been made by the
Treasury in conjunction with the War Office and Board of
Trade (Timber Section), whereby compensation for extra-
ordinary damage to public roads caused by timber haulage
for national purposes will be dealt with by the Controller
of Roads and Bridges, Lands Directorate, War Office, in
communication with the Road Board. Road Control
officers have been appointed by the Army Council, one
of whose duties will be to give instructions controlling
timber traffic on public roads in accordance with Army
Council Order of the 15th instant, issued under Regulation
5c of the Defence of the Realm Regulations, and published
in the London Gazette of the 19th inst. Their duties will
be carried out in the closest co-operation with the various
highway authorities concerned in order to assist in
reduction of avoidable damage to roads. The Road
Control officers will in no way interfere with the statutory
duties or responsibilities of any highway authority.

SALINE OIL COKE.

Mr. H. Scragg read a paper on “The Deleterious
Effect of Using Saline Oil Coke in the Manufacture of
Carbon Electrodes” before the Newcastle Section of
the Society of Chemical Industry last week. He stated
that his object was to show the adverse influence of the
presence of salt in the manufacture of amorphous
carbon electrodes where high density and purity were
the essential features aimed at. The saline oil coke was
chiefly derived from Russia, presumably from around
the Black Sea, and contained from 6 to 7 per cent, of
sodium chloride. Scottish oil coke, however, was free
from such impurity and gave rise to no trouble. The
following was an analysis of saline oil coke:—Moisturej
2 89 per cent.; volatile matter, 4'65 per cent.; insoluble
ash, 0’80 per cent.; sodium chloride, 6'40 per cent.; and
carbon (by difference), 85’26 per cent. It was obvious
from that analysis that the sodium chloride could very
readily be washed out by suitable means with hot water,
yet it struck one that, during calcination, a loss of
sodium chloride would occur. That, however, was based
on the supposition that the temperature attained in a
furnace would be as high as usual, but it had been
found that the presence of sodium chloride seemed to
prevent such a high temperature being attained as with
saline-free oil coke, when the temperature would be as
high as from 1,400 degs. Cent, to 1,500 degs. Cent., the
lowest being from 1,100 to 1,200 degs. Cent. It was
found that the highest temperature recorded when
calcining saline oil coke was 1,100 degs. Cent., whilst,
in parts, it was as low as 880 degs. Cent. That
circumstance had an important bearing on the question,
as it did not allow of the volatile sodium chloride
being expelled, but merely passing from one portion of
the furnace to anotber, finally condensing on the cooler
coke on the top, or dropping back into the furnace when
the lower portion was withdrawn. Instead of a loss of
sodium chloride, a process of concentration would go on
until the furnace was finally drawn. Moreover, the
density of the oil coke was not what might be desired.
In practice, it had been found that the sodium chloride
increased from 6 per cent, in the original to 8 per cent,
in the calcined, and, at the same time, the insoluble ash
rose from 0’80 per cent, to 1’2 per cent. The latter was
very probably due to the action of fused chloride upon
the furnace lining. It would, indeed, be very bad policy
to attempt to make • electrodes from the calcined
material, and, apart from washing out the soluble
chloride, the only alternative would be to dilute coke
with other oil cokes free from salt, thereby obtaining a
mixture containing, say, 2 per cent. NaGl. There,
again, on mixing the ground coke containing from 1 to
2 per cent. Nad with suitable binding material, and
pressing the whole into block form and baking, a further
set-back was experienced. The density of a finished
electrode should be at least 2—that was, to obtain any
life out of it—and, from figures quoted, it would seem
that, in the case of electrodes containing salt, the density
fell with increasing percentage of that impurity. Thus,
with oil coke containing 1’51 per cent, of NaCl, the
density was 1’95; with 1’63 per cent., 1’92, and with
1’78 per cent., 189; whilst another block, baked at
the same time but free from salt, had a density of 2.
The presence of sodium chloride only would tend to
make the density more than normal, supposing, of
course, that the remainder of the block attained a
density of 2, so that it was quite evident that the low
density must be accounted for in other ways—e.g. (1)
low temperature of calcining with saline oil coke; (2)
improper baking temperature; and (3) sodium chloride
in the block preventing the escape of volatile matter. In
the case of improper baking temperature, it was found
that an electrode free from chloride and baked alongside
of some containing salt, attained a density of 2. Many
of the electrodes, when finished, were found to be blis-
tered and to have whitish marks on the face. These
blisters also pointed to the volatile matter being unable
to escape.

The Chairman (Mr. Hy. Peile) said he did not
know whether the presence of salt in an electrode would
have a bad effect in a steel furnace. He believed
Mr. Scragg was mostly interested in the manufacture
of electrodes for the aluminium process, not for ordinary
metallurgical work. There seemed to be little doubt
that the presence of salt had a bad effect, but it was
difficult to say to what it was due.

Dr. J. T. Dunn, public analyst, remarked that he
should have thought that it would have been possible to
wash out the salt. Perhaps Mr. Scragg assumed on the
part of his hearers a little more technical knowledge
than they possessed. The speaker did not understand
exactly what was done with that coke, how it was treated
in detail.

The Chairman explained that all the best oil coke at
present was being used in the manufacture of aluminium.
The oil coke used for making electrodes was mixed with
other ingredients, such as gas carbon and anthracite,
the result of which was to give a better product than
was procurable from any one sort of carbon.

Mr. F. Campbell observed that, with reference to
steel furnaces, he thought the only trouble would be
that salt would damage the bricks and make them run.
It would not interfere with the steel; in any case, it
would be volatilised before it got into the steel. One of
the troubles in making aluminium was that, if the
furnace got too hot, there was much more sodium
formed.

Mr. W. Jones said he recently had occasion to
examine some Scottish coke, and found it to contain
from 3 to 4 per cent, of sulphate of soda. Very often,
Scottish coke contained as much as 5 per cent, of that
sulphate.

The Chairman said the best cokes made in Scotland
were free from salt, but some Scottish cokes contained it.