NEWS

Lunge states 75 per cent of the loss takes place in the chambers themselves; this is equal to 45 cwts.

Now the putting up of the towers can scarcely be thought to have exerted any influence upon the nitre-decomposing power of the chambers, as the drips and acids were worked to be of the same strength as before their erection. What was then the total nitrate of soda used weekly? 16 cwts., or 29 cwts. less than Lunge says the chambers alone will decompose. Lunge's theory, then, must evidently be a false one.

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Hurter states that the chambers would decompose 12 cwts., leaving 4 cwts. to be accounted for in other ways. But he has accounted for them, and let us see how his theory works:

08"

PROBABLE BEHAVIOUR OF VARIOUS METALS AND THEIR COMPOUNDS WHEN SUBJECTED TO RAPID OXIDATION.

To the Editor of the Chemical News. SIR,-Having received much assistance from chemists, and knowing the interest taken by them in the experiments which have been made at the works of Messrs. Charles Cammell and Co., Penistone, and at those of Messrs. John Brown and Co,, Sheffield, I venture to hope that I may be favoured by the advice and assistance of some of your readers as to the probable behaviour of various metals and their compounds when subjected to rapid oxidation.

We will assume that the charges treated consist of sulphides, arsenides, &c., and contain a sufficient proportion of oxidisable materials to produce the necessary heat for their fusion, decomposition, and volatilisation of the sublimates. That iron, lead, gold, silver, copper, nickel, antimony, zinc, arsenic, and sulphur are present as well as sufficient silica to combine with the protoxide of iron produced, so as to form 2FeO,SiO2, and also an additional quantity of silica with the necessary lime or other bases to neutralise same so as to form a slag of specific gravity

3'4.

To avoid giving unnecessary trouble, I will briefly state my ideas as to their behaviour, and I trust your readers will kindly correct any errors I may make, as by so doing they will greatly oblige me, and thus assist me in my further experiments.

The Iron would be partially or entirely oxidised, and combine with the silica so as to form 2FeO,SiO2+silicate of lime, &c.; part of the iron might remain in the regulus as FeS and Fe.

The Lead would probably distil off and be collected as PbS; but it is possible that metallic lead might be reduced by the PbO produced reacting on PBS, i.e.,—

PbS+2PbO=3Pb+SO2.

If metallic lead is produced it would collect in the quiescent

The Antimony and Zinc would be volatilised and collected as oxides.

The Arsenic would probably distil off as sulphide of arsenic, although part might be oxidised to arsenious acid. The Sulphur not found in the regulus or combined with arsenic would partly distil off as sulphur, and the remainder would be oxidised and pass off as SO2.-I am, &c., JOHN HOLLWAY.

Jeffrey's Square, St. Mary Axe, London, E.C., May 10, 1879.

OBITUARY.

THOMAS WILLS, F.C.S.

MANY of our readers will have heard with regret of the very sudden death of Mr. Thomas Wills, who has acted as Secretary to the Chemical Section of the Society of Arts since it was first founded in 1874. From the Journal of the Society we learn that Mr. Wills was born in 1850, in Devonshire; he was educated at University College School and at King's College. In the early part of 1868 he became an assistant to Dr. Odling at St. Bartholomew's Hospital, and in the latter part of that year, on Dr. Odling being elected to the Fullerian professorship at the Royal Institution, Mr. Wills was appointed his official assistant. In 1873 he accepted the position of Demonstrator in Chemistry at the Royal Naval College. The subject to which he specially devoted himself was the application of chemistry to the manufacture of gas, and on questions connected with this subject he was rapidly becoming an authority. He held for some time the position of chemist to the Phoenix Gas Company. In 1873, previous to his official connection with the Society of Arts, he read a paper on "The Manufacture of Gas," and last year he gave a short course of lectures before the Society on Explosions in Coal Mines." For several years he acted as Secretary to Section B of the British Association, and he was a member of the Association Committee for ascertaining the best methods of improving the illuminating power of coal gas. His most recent piece of work was in connection with the subject of electric lighting. Dr. Tyndall, in giving evidence upon the electric light before a Committee of the House of Commons, referred to Mr. Wills as having discovered that oxides of nitrogen were given off by the voltaic arc, thus rendering the light to that extent ́injurious. His death was most sudden and unexpected. He fell a victim to typhoid fever, which carried him off after an illness of less than a week. He was only twenty-eight years of age at the time of his death.

66

New Books.-The first volume of "A Treatise on the Manufacture of Sulphuric Acid and Alkalies," by Prof. Lunge, will, we understand, be published very shortly by Mr. Van Voorst. The work will be fully illustrated, and be complete in two volumes. The same publisher has in the press a supplement to Mr. C. Greville Williams's "Handbook of Chemical Manipulation."

220

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CHEMICAL NEWS. May 23, 1879.

Blows. Si

P

C

I'21 I'21

trace I'21

0'06

none 0'50

II. trace I'19 under ΟΙΟ Ο ΙΟ

1. trace I'II

ΟΙΟ

Steel.

11. trace I'II

0'54 0'42 0'05 0'09 Mr. Jenkins, of Dowlais, has kindly furnished us with his analyses of the same blows. He finds 108 in the steel from the first blow, and r03 in the steel from the second blow.

The cinder with the steel contained in the first blow 38.8 per cent of silica, and in the second blow 36.18. The pig used was too high in silicon for phosphorus to be readily removed, without very large additions of lime. In the third blow 33 cwts. of a mixture of two parts of lime to one of roll scale were thrown into the converter before the metal was run in. The metal was blown for eight or nine minutes and turned down (before the flame dropped). Nearly another 3 cwts. of the same mixture was then thrown in, and the vessel again turned up, when the flame dropped almost immediately. After being turned down for some fifty seconds, it was (at Mr. Martin's suggestion) again blown for nearly a minute. Though it appeared that the metal was overblown, the action, on adding spiegel, was not violent. A large skull was, however, left in the converter and ladle, and much slag was produced. The blow lasted ten and a half minutes. A rail made from one of the ingots deflected 98 inches with the blow of I-ton ball falling 24 feet, the bearings being 3 feet apart. It was considered much too soft for rails. The skull left in the converter was got out by blowing a charge of very siliceous non-phosphoretic pig. In the next (fifth) blow, I cwt. of a mixture of two of limestone and one of Elba ore was thrown cold into the converter before the metal was run in; rather over 3 cwts. of heated roll-scale was added subsequently, before the completion of the blow. During this blow the lining had to be patched at the breast.

The results appear to confirm the conclusion that, for the process to be of technical value, waste of lining and metal must be avoided by making large basic additions, so as to secure a highly basic calcareous slag at an early stage of the blow. In these trials, however, it was thought prudent to feel the way, and not add at once the very large amount of base which our theory demanded, the more so as we were not able to add the bases in the molten state. It is also made clear that a slag containing under 14 per cent of iron may be very effective in removing phosphorus.

After the five blows described the lining was found to be much worn, and not in a condition to admit of satisfactory repairs. Two tuyeres had to be renewed in the fourth blow; the rest stood well.

It is obvious that without a sufficiently durable, as well as refractory, basic lining, the simultaneous dephosphor

isation and conversion of cheap pig in the Bessemer vessel cannot rank as a commercial process. Our early experiments rendered it clear that ordinary non-siliceous lime and limestone did not constitute by themselves a satisfactory lining material; nor were renewed trials, made after becoming acquainted with a patent dealing with their application, more successful. Magnesia, the use of which as a furnace lining has been suggested by M. Caron and others, is at once very expensive and-when used by itself it at all practicable on the large scale to use oxide of iron linings in any of the forms in which they have been used in puddling furnaces. After a very extended series of trials. it was, however, found that, by firing bricks made of an alumino-siliceous limestone at a very intense white heat, a hard and compact basic brick is formed. These bricks unfortunately labour under the defect of a liability to disintegration when exposed to the action of steam. By the use of certain aluminous magnesian limestones and equivalent combinations, and an otherwise similar mode of manufacture, this difficulty has been overcome. For certain purposes magnesian limestone, mixed with silicate of soda solution, forms an excellent material. To enter fully into the important subject of the precise conditions necessary for obtaining a satisfactory basic lining would exceed our limits, and the consideration of this, as of many other interesting points, must be reserved. The question of how far the heat due to the oxidation of phosphorus may replace that due to the combustion of silicon, the possibility of using in the converter low phosphoretic pig low in silicon, and the influence of silicon on the removal of phosphorus, are some of the subjects on which much remains to be said.

In advancing the proposition that the technical removal of phosphorus in the Bessemer converter is simply and entirely a question of cheaply producing a highly basic slag, containing under 20 per cent silica and over 30 per cent of lime and magnesia, and indicating the means by which this may be secured, we are not aware that we can shelter ourselves under any very distinct authority, though surmises as to the hypothetical advantages that might be expected, were the Bessemer slag less siliceous, have not been wanting. It is, however, only proper that we should remind the Institute that Mr. Snelus stated at its March meeting simultaneously with ourselves that he had removed phosphorus in a Bessemer converter lined with limestone. Of the circumstances of this experiment we are in ignorance. It is on the production of a basic earthy slag, by the addition of large quantities of calcareous bases, and without excessive waste of lining and metal, and the construction of a durable basic lining, that we venture to think the economic solution of the phosphorus problem depends.

It need hardly be said that the theory here advanced as to the practicability of commercially removing phosphorus in the converter extends, mutatis mutandis, to the Siemens and other open-hearth processes, where, in fact, many difficulties that are met with in the converter are absent. Dr. Siemens has indeed suggested the use of a lime lining in one of his furnaces, though he has since, with his customary candour, informed us that he has failed to devise means for its successful application. The present paper will have fulfilled its purpose if it induces metallurgists to reconsider the verdict, so fatal to the hopes of steelmakers, that "oxygen, whether in its free state or as oxide of iron, is almost entirely inert as regards phosphorus at the intense temperature which accompanies the Bessemer process.

In the nine months that have elapsed since our paper on the "Elimination of Phosphorus," &c., was prepared, the vigerous co-operation of Mr. Windsor Richards and

* For most valuable assistance in these, as at every period of this investigation, we are especially indebted to Mr. Thomas Griffiths, engineer at Blaenavon. We take the opportunity of at the same time thanking Mr. Gill, assistant in the Blaenavon laboratory, for his aid in the many hundreds of analyses made in the course of our inquiry.

NEWS

Messrs. Bolckow Vaughan has enabled the authors to submit to the Institute further evidence in support of the views then put forward. That intensity of temperature is no obstacle to the removal of phosphorus, but, under proper conditions, highly favourable to this end, has been abundantly demonstrated by the results of the working at Middlesborough. It is indeed found that, other things being equal, the hotter the blow the better is the result. As regards the necessity for large additions of bases consisting mainly of line, the experience afforded by some seventy or eighty operations is equally conclusive.

In continuation of some smaller experiments carried out in 1877 at Blaenavon, trials have been made of the effect of largely increasing the amount of oxide of iron added at the commencement of the blow, and diminishing the lime so as in a measure to assimilate the cylinder to that of a puddling furnace. As was anticipated, it was found that this could not be done successfully. In the first place, the loss from excessive boiling was very great; in the second, the phosphorus is only very imperfectly removed. A very considerable amount of ore may, however, be added after the greater part of the silicon is removed. The amount of bases which it is necessary to add with Cleveland pig generally exceeds considerably 2 cwts. per ton of pig treated, the exact amount being dependent on the wear of the bottom, and the percentage of silicon and phosphorus in the pig. The presence of an excess of earthy base in the slag seems an essential condition of success. The formation of a very fluid basic slag at an early stage of the operation is also of great importance, as it enables the phosphorus and carbon to be oxidised pari passu, or nearly so. It will be borne in mind that the basic addition has a double function; in the first place, to preserve the lining; in the second, to form a highly basic earthy slag, so as to afford a strong base with which the phosphoric acid may unite at the moment of its formation. On several occasions the experiment has been made of blowing in a basic brick lining without, or with very small, addition. The result is always excessive damage to the lining and a trifling removal of phosphorus. The density and compactness of the present lining material prevents it from playing the important part in the actual formation of the basic slag which was fulfilled by the softer and less durable linings first experimented on. The highly-freed magnesian lime bricks have, we venture to think, more than fulfilled all the expectations which were entertained as to their probable value.

It has also been ascertained that, providing a highly earthy basic slag is present, the removal of almost the last traces of phosphorus may be secured by continuing the blow for some time after the drop of the flame. The phosphorus in the presence of a strong base seems to protect the metal much in the same way as carbon and silicon, so long as there is present an excess of a strong base with which the phosphoric acid can unite at the moment of its formation. When, however, the phosphorus is reduced very low, the iron begins to oxidise as in an ordinary case of over-blow.

The question of the elimination of phosphorus being the primary matter with steel-makers, it is not proposed to do more than to mention that, under the circumstances which have been described as essential to the removal of phosphorus, a considerable proportion-viz., from 30 to 70 per cent of the sulphur is also removed. Certain experiments made by the authors in conjunction with M. Ponsard, in November last, with a Ponsard furnace,—in the first of which over 80 per cent of the phosphorus and 50 per cent of the sulphur were removed under very unfavourable conditions,-quite confirm the opinion formed from smaller experiments, that the system described is as applicable to the open-hearth as to the Bessemer furnace. Those open-hearth furnaces which are provided with removal hearths offer peculiar facilities for the adoption of brick hearth or lining.

PEROXIDE OF HYDROGEN.*

By GEORGE E. DAVIS.

MOST books tell us that H2O2 is made by a roundabout process with BaO2 and HCI; this might have been in days gone by, but now it is made principally by means of barium peroxide and hydrofluoric or fluosilicic acids. An insoluble fluoride of barium or fluosilicate is formed which separates at once and peroxide of hydrogen remains. Now, if hydrofluoric or hydro-fluosilicic acids have been used, we need not expect to find hydrochloric, as this latter can only be present when impure fluoride is used, impure acids, or impure water. Of course it is absolutely necessary to examine carefully every sample of peroxide of hydrogen which may be purchased, for many statements have been made at various times respecting the purity of the bought article. One chemist assured me that the first lot he purchased was full of hydrochloric acid, whilst another chemist actually assured me that peroxide of hydrogen would not oxidise sulphide of sodium in vat liquors. More statements than these have been made respecting the efficiency of this reagent, but in each and every case it would have been more creditable to the author of the statement had he examined thoroughly the facts of the case before making complaint against one of the most useful articles used in chemical analysis.

Now, the first thing which requires to be estimated is the active oxygen, and this may be seen when I state that the sample which would not oxidise sulphide of sodium contained only a trace of active oxygen. Many methods may be devised for estimating the strength of this article. I have used the following three methods with satisfactory results:

I c.c. was put into Crum's tube over mercury and run underneath the tap; then 5 c.c. of a saturated solution of bichromate of potash, the whole gently agitated, the liberated oxygen measured and corrected for temperature and pressure. In working on a certain sample as a mean of several experiments, I c.c. gave 8.2 c.c. of oxygen at o° C. and 760 m.m.

By a second method to c.c. of the peroxide were boiled with 20 c.c. of sulphurous acid, and the sulphuric acid which was formed precipitated as barium salt and weighed; the sulphuric acid existing as such in the sulphurous acid being deducted from the precipitate. 10 c.c. oxidised 0.46 grm. SO2, or 7.08 grs.

By a third method 10 c.c. of the peroxide oxidised 146 c.c. protosulphate of iron. Now, if we calculate these we shall find that our first method gives the strength of the solution as 8.2 volumes, and they all, when expressed as in grammes of oxygen per litre, show:11.72 b. 11:53 C. 11.68

a.

For general work the bichromate method is preferable, though when extreme accuracy is required the iron method may be employed if conducted in a stream of carbonic acid.

Now, as to the stability of peroxide of hydrogen. It has been stated quite recently, and by one of the members of this Club, that it is so unstable that simply drawing air through a solution of it will abstract the whole of its active oxygen. I don't know what amount of air is considered necessary, but I should say a great deal, and neither do I know what tests he used to ascertain that there was no peroxide left undecomposed. An alkaline solution of peroxide is partly decomposed by agitation only, but an acid or neutral solution is very stable. An alkaline solution of peroxide has been used over a very long time in connection with a continuous aspirator, 10 c.c. of peroxide and the necessary quantity of water

* A Paper read before the Faraday Club.