466 



SCIENCE 



[N. S. Vol. L. No. 129 



specific gravity of not over 2.38. Some quartzites 

 invert to cristobalite more slowly than others and 

 hrick with a lesser content of cristobalite have a 

 lower spalling tendency and also do not show an 

 ajppreciably greater permanent expansion when 

 subjected to long-continued heating. Brick made 

 from this type of quartzite may be properly 

 burned when inversion has occured to such an ex- 

 tent that its specific gravity is slightly greater 

 than 2.38. Examples with analyses are given. 

 Metal-cased magnesite brick consist of steel con- 

 tainers of square or circular cross section, filled 

 with dead burned magnesite. These are laid as 

 headers in the furnaces. When heated the steel 

 fuses and impregnates the magnesite forming a 

 monolithic lining. Such a lining is more porous 

 than one of magnesite bricks and has the advan- 

 tage of better withstanding rapid temperature 

 changes. Such bricks may be used in place of 

 magnesia and silica brick in parts of the open 

 hearth steel furnace and in electric steel melting 

 furnaces. 



Interesting facts concerning refractories in the 

 iron and steel industry: C. E. Nesbitt and M. L. 

 Bell. In this paper the writers state the im- 

 portance of refractories and emphasize the neces- 

 sity for their greater efficiency in the iron and 

 steel industry. This improvement can only be 

 accomplished by the cooperation of the producer 

 and the consumer. In the manufacture of iron 

 and steel, refractories meet a wide range of tem- 

 perature, while destructive agencies such as acid, 

 basic or neutral slags, severe thermal changes, load, 

 ajbrasion, impact and expansion are present in 

 varying degrees of severity. Tests on refractory 

 brick, easily and rapidly executed, which show a 

 close relation to actual service conditions were 

 developed for determining the resistance to these 

 destructive agencies. The most important work- 

 ing qualities can be determined by two or three 

 tests namely the spalling and hot crushing tests 

 for silica brick, and the spalling, hot load and 

 slagging tests for clay brick. Variations in the 

 Jife of blast furnace linings, open hearth roofs, 

 converter bottoms soaking pits and ladle linings 

 are mentioned. Besults are given showing the 

 marked decrease in crushing strength and increase 

 in spalling of silica brick defective from fire 

 cracks, poor moulding, poor slicking, etc. The 

 writers show the close relationship of the spalling 

 test results with the life obtained in open hearth 

 roofs. The effect of the degree of fineness or 

 size of particles in silica brick is illustrated by re- 



sults of the spalling test. The effect on certain 

 qualities of clay brick produced by the method of 

 nianuf aoture is illustrated by spalling and load test 

 results. The effect of the degree of fineness and 

 the reduction of strength by heating of clay brick 

 js also shown. From the comparative data it is 

 evident that refractories require most thorough 

 study. Simple practical tests which can be run in 

 quantity and which give data showing variations 

 jn quality which reflect on the life of the struc- 

 ture should be adopted. A more uniform product 

 can be secured if a careful study is made of the 

 yariations in manufacture which effect the im- 

 portant qualities. 



Superior refractories : E. C. Puedy. 



Eefractory problems in the gas industry: W. H. 

 EuLWEiLEE and J. H. Taussig. In the coal gas 

 jprocess the temperatures range from 400° 0. to 

 ^500° C. Bapid changes in temperature and ex- 

 .pansion must be considered. Siliea material is 

 .used in the retorts and the combustion chamber. 

 JPire clay material is used in the recuperators and 

 where the temperature is below 1000° C. In the 

 .water gas process the temperature may be 1700° 

 p. in the generator, together with the slagging ac- 

 tion due to the ash from the fuel. Abrasion oc- 

 curring in removing clinker is important. In the 

 carburettor the checker brick are heated to 1200° 

 C. and sprayed with cold oil. Eire clay is used in 

 ^the generator linings, but other materials are 

 being tried. Cements used in construction fre- 

 quently do not receive proper attention. Labora- 

 tory tests are useful in controlling the quality of 

 materials. 



Charles L. Parsons, 



Secretary 



SCIENCE 



A Weekly Journal devoted to the Advancement of 

 Science, publishing the official notices and pro- 

 ceedings of the American Association for ' 

 the Advancement of Science 



Published every Friday by 



THE SCIENCE PRESS 



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Entered in tbe po«t-e£ce «t Lancuter. Pa., as lecond cI«h pi^t tfy 



