Aug., 1922
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
749
LONDON LETTER B y HUGHGRIBFITHS, 15 h’ew Bridge St., London, E. C . 4, England
THE SAFEGUARDING OF INDUSTRIES ACT The Key Industries bill is still engaging close attention, and two very interesting complaints have been heard by the Official Referee. Hitherto, in most of the complaints, discussion has been directed towards ascertaining the meaning of the term “fine chemical;” in the case of “synthetic camphor” the discussion was more particularly directed to fixing the meaning of the term “synthetic.” The decision of the Referee, which was given at great length, cannot be considered as other than masterly, and one feels, after reading this decision, that the synthetic chemical has been put in its place once and for all, and that the limitations of the term “synthetic” have been defined for the benefit of posterity. The essential point of the award is that both pinene and synthetic camphor are removed from the list, and Komppa’s synthetic camphor added. Some very interesting facts were disclosed in the course of evidence, a witness stating that one firm purchased camphor during 1913 to the value of 2100,000. The difficulties imposed upon the producers of turpentine camphor by the Japanese producers of natural camphor were also mentioned. Most chemists will feel that it is unfortunate that an important industry such as the production of turpentine camphor should be completely beaten out of existence, and it is common knowledge that every concern which has attempted to produce this material commercially in England has been subsequently compelled to abandon its operations. The experience in the United States has been somewhat similar. A complaint regarding incandescent gas mantles has also been heard, and it has been decided that incandescent gas mantles, being “mechanical aggregates of oxides of thorium and cerium,” are included in the phrase “compounds of thorium and cerium, etc.,” and are to be included in the list. A further inquiry is now being held under Section 2 of the Act, and an endeavor is being made to get a duty of 331/8per cent imposed on all incandescent mantles imported from Germany. BRITISHDYESTUFFS INDUSTRY During the war it was reported in this country that a very subtle individual had succeeded in obtaining all the “secrets” of dye manufacture, as practiced in Germany, and that the documents were on the way from Switzerland, securely packed in a foreign office bag. This statement was met with great scorn by technical men, and it was pointed out that the accumulated experience of forty years cbuld not be so easily lifted. A disquieting announcement has now been made, that the representatives of the British dye manufacturing concerns are in negotiation with the German producers at the present moment, with a view to securing cooperation in some form. It is of course well known that the producers of dyestuffs in this country have been losing money for some time, and i t is not surprising that these negotiations are in progress. The question arises, however, whether any good can come from these conversations, which must be regarded in the nature of a confession of failure. This matter is very strongly discussed in technical circles, where it is fully realized that mere recipes and information regarding the technic of manufacturing processes will not be sufficient to save the industry. The essential difficulties of the British dye industry may appear at first to be technical difficulties, but it must be remembered that all the plants were put down at a time when market conditions were quite artificial, and since the various works were designed the market conditions for every product have received rude shocks. Even under conditions of normal demand and steady markets the organization of a dye industry, with its interlocking ramifications, is no mean problem. At a time when the world’s markets are in a state of upheaval, proper organization and coordination of the various activities are almost beyond human powers, and steady efficient working of manufacturing plants cannot possibly be achieved, nor could all the accumulated skill and technical experience in the whole of Germany, or elsewhere, solve this problem at the present time. It is felt in this country that, a t any cost, this industry must not be allowed to collapse, and that the only solution lies in adequate financial support until the industry can work out its own salvation.
FINEGRINDINGAND INCORPORATION Since the somewhat bitter controversy between Gates and Stadler, very few contributions to the theory of fine grinding have been made, and the study of the energy efficiency and the mechanism of pulverization has been handicapped to some extent by the difficulty of obtaining a satisfactory means of grading powdered materials of a fineness much below 200 mesh. In this connection, the investigations made by Dr. T. M. Lowry in England are of special interest. At a recent joint meeting of the Faraday Society and the Oil and Colour Chemists Association, this subject was discussed. While many of the advantages of grading by means of air currents were pointed out and fully appreciated from the commercial point of view, a precision apparatus for elutriation tests was described, and the various conditions controlling the accuracy of the instrument detailed. Apparently this instrument was designed to provide a satisfactory test for barytes for works use, and probably will be applied to the study of the products from fine grinding machines. A particularly interesting field of application should be in the study of the coarser products of the colloid mill. Another important subject has been investigated by E. P. Perman, namely, the testing of the degree of incorporation of explosives and similar materials. While it is a simple matter by ordinary analytical methods to study the coarse mixing of materials in a mill, it has been pointed out by Perman that in order to secure a test of incorporation very minute samples must be taken, and in the case of the mixture chosen, containing ammonium nitrate and TNT, samples of about 1mm. each were examined by a Nessler method. The figures of mean deviation enabled the effect-variations in time of milling, weight of charge, and miling speed, to be traced accurately.
THE COLLOIDMILL Great interest has been shown in this country in Plauson’s colloid mill. This machine has been specially designed for the reduction of materials to very small dimensions, in some cases down to 0.01 p. The writer has had the privilege of seeing one of these machines in operation a t Erfurt, and has also been able to discuss the mill with the inventor. and Herr Block of Emil Passburn Maschinenfabrik, who was ’responsible for the mechanical details of the design. The machine consists of a circular casing, with an eccentrically placed rotor which is driven a t a very high peripheral speed. The casing contains a liquid, and the machine therefore consists, in principle, of an impact disintegrator in which the material is pulverized in the presence of a liquid. With this device, it is claimed, a much larger proportion of small particles of the order of magnitude of 0.01 p can be obtained, than in any dry disintegrator or in any ordinary system of wet grinding. The claims appear to be established, and the commercial possibilities of the machine look interesting. It is possible, by the use of dispersion accelerating agents, to increase the production of fine particles and to produce stable emulsions and dispersions in the machine, from all kinds of materials, Mercury can be dispersed in water to the form of a stable colloidal mercury of high concentration. The machine has also been applied to the production of colloidal fuel, homogenized milk, viscose, lubricants, and many other materials. Most of these substances have been treated experimentally with very interesting results, but so far as this country is concerned little is known regarding the commercial exploitation of the machine. Several German firms have installed machines for commercial use, but it is fairly obvious from the scope which this machine offers, that it will be some time before the commercial applications can be fully investigated. It is at present extremely difficult to say which of the applications will prove profitable, but from a scientific point of view the results will be looked for with very great interest. PLAUSON’S ULTRA-FILTER
The inventor of the colloid mill has also patented some new types of filtering surface of adjustable porosity. The apparatus
