When the alkali, etc., Works Regulation Act was passed in 1881, it was
supposed that the result would be that the atmosphere in the districts
where such works are situated would be considerably improved, and,
consequently, that vegetation would have a better chance in the
struggle for existence, and the sanitary conditions of human dwellings
would be advanced. In all these respects the act has been a success.
But perhaps the most notable result is the effect which the act and
those which have preceded it have had upon the manufactures which they
control.
This was not anticipated by manufacturers, but now one of the
principal of them (Mr. A. M. Chance) has stated that "Government
inspection has not only led to material improvement in the general
management of chemical works, but it has also been in reality a
distinct benefit to, rather than a tax upon, the owners of such
works."
This expression of opinion is substantiated by the chief inspector
under the act, whose report for last year has recently been laid
before the local government board.
There are 1,057 works in the United Kingdom which are visited by the
inspectors, and in only two of these during 1888 did the neglect to
carry out the inspectors' warnings become so flagrant as to call for
legal interference; viz., in the case of Thomas Farmer & Co.
(limited), Victoria Docks, E., who were fined 20l. and costs for
failing to use the "best practicable means" for preventing the escape
of acid gas from manure plant; and in the case of Joseph Fison & Co.,
Bramford, who were fined 50l. and costs for excessive escape of acid
gas from sulphuric acid plant. There were seven other cases, but these
were simply for failure to register under the act.
It is very evident, therefore, that from a public point of view the
act is splendidly successful, and from the practical or scientific
side it is no less satisfactory.
Of the total number of chemical works (1,057) 866 are registered in
England, 131 in Scotland, and 44 in Ireland--a decrease in the case of
Scotland of 8, and in Ireland of 2 from the previous year, while
England has increased by 1. This must not, however, be taken as a sign
of diminished production, because there is a tendency for the larger
works to increase in size and for the smaller ones to close their
operations. The principal nuisances which the inspectors have to
prevent are the escape of hydrochloric acid gas from alkali works and
of sulphurous gas from vitriol and manure works.
The alkali act forbids the manufacturer to allow the escape of more
than 5 per cent. of the hydrochloric acid which he produces, or that
that acid must not exist to a greater extent than 0.2 grain in 1 cubic
foot of air, steam, or chimney gas which accompanies. The inspectors'
figures for last year show that the percentage of the acid which
escaped amounted to only 1.96 of the total produced, which is equal to
0.089 grain per cubic foot, and much below the figures for previous
years. The figures in regard to sulphurous gas are equally
satisfactory. The act allows 4 grains of sulphuric anhydride (SO3) per
cubic foot to escape into the air, and last year's average was only
0.737 grain, or less than a fifth of the limit.
Of course it is now the aim of the Leblanc alkali manufacturers to
reduce the escape of hydrochloric acid to the lowest possible amount,
as their profits depend solely upon the sale of chlorine products,
soda products being sold at a loss. In this connection it is
interesting to note that the amount of common salt manufactured in the
United Kingdom in 1888 was 2,039,867 tons, and of this nearly 600,000
tons were taken by Leblanc soda makers, and over 200,000 tons by the
ammonia-soda makers. The figures are very largely in excess of
previous years, and indicate a gratifying growth in trade.
The salt used in the Leblanc process yields the hydrochloric acid, and
that in the ammonia-soda method none, so that we may put down the
theoretical production of acid as 380,000 tons, 7,600 tons of which
was allowed to escape.
What was a mere trace in the chimney gases amounts, therefore, to a
good round figure at the end of a year, and if it were converted into
bleaching powder it would be worth nearly 150,000l. These figures are,
it should be understood, based on theory, but they serve to show to
what importance a gas has now reached which twenty-five years ago was
a perfect incubus to the manufacturers, and wrought desolation in the
country sides miles and miles around the producing works. There has
long been an expectation that the ammonia-soda makers would add the
manufacture of bleaching powder to their process, but they appear to
be as far as ever from that result, and meanwhile the Leblanc makers
are honestly striving to utilize every atom of the valuable material
which they handle. Hence the eagerness to recover the sulphur from
tank waste by one or other of the few workable processes which have
been proposed.
This waste contains from 11 to 15 per cent. of sulphur, and when it is
stated that the total amount of tank waste produced yearly is about
750,000 tons, containing about 100,000 tons of sulphur, it will be
seen how large is the reward held out to the successful manipulator.
Moreover, the value of the sulphur that might possibly be saved is not
the only prize held out to those who can successfully deal with the
waste, for this material is not only thrown away as useless, but much
expense is incurred in the throwing.
In Lancashire and in other inland districts land must be found on
which to deposit it, and the act of depositing is costly, for unless
it is beaten together so as to exclude the air, an intolerable
nuisance arises from it. The cost of haulage and deposit on land
varies, according to the district, from 1s. to 1s. 6d. a ton. In
Widnes it is about 1s.
In the Newcastle district the practice is to carry this material out
to sea at a cost of about 4d. a ton.
Mr. Chance's process for the recovery of sulphur from the waste
signalizes the centenary of the Leblanc process; Parnell and Simpson
are following in his wake, and lately Mr. F. Gossage, of Widnes, has
been working on a process for the production of alkali, which enables
him to save the sulphur of the sulphuric acid. In his process a
mixture of 70 parts Leblanc salt cake (sulphate of soda) and 30 parts
common salt is mixed with coal and heated in a furnace, and so reduced
to sulphide of sodium. The resulting "ash" is then dissolved in water
and exposed to the action of carbonic acid, when sulphureted hydrogen
is given off, to be dealt with as in Mr. Chance's sulphur process,
while bicarbonate of soda is formed and separates by precipitation
from the solution of undecomposed common salt.
Ere long it is expected this new method will be in active operation in
some Leblanc works, the plant of which will, in all probability, be
utilized. It has these great advantages: The absence of lime, the
recovery of the sulphur used in the first instance and the consequent
absence of the objectionable tank waste. Thus a bright promise is held
out that the days of alkali waste are numbered, and that the air in
certain parts of Lancashire will be more balmy than it has been in the
memory of the oldest inhabitant.--_Chemist and Druggist._
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