14—COMPARISON OF THE FELTING PROPERTIES OF LOOSE WOOL FIBRES,WORSTED-SPUN YARN,AND KNITTED FABRIC

When the felting properties of loose wool, yarn, and fabric are compared, before and after chemical modification, only a poor relationship is found between the felting rates of all three assemblies. It is therefore impossible to predict the effect of a particular treatment on a fabric by applying the same conditions of treatment to the loose wool. A very detailed study of a particular treatment is necessary before loose-wool felting can be used for prediction purposes.     

Formation of potassium slag in olivine fluxed blast furnace pellets

Abstract

Mineralogical evaluation of olivine pellets coated with kaolinite, taken from the LKAB experimental blast furnace, shows significant reactions with potassium. Sampling has revealed strong potassium deposition in pellets in the lower shaft close to the wall, but much less deposition towards the furnace centre. Iron reduction and the deformation of the pellets were enhanced in the zone of high alkali deposition. Thin sections of pellet samples were prepared to distinguish amorphous and crystalline slag phases for a better understanding of the formation of the potassium rich slag. Olivine breaks down to various extents to form a SiO₂–FeO–MgO–K₂O glass. The kaolinite coating shows strong reaction throughout the cross-section of the lower shaft to form kalsilite (KAlSiO₄) and K₂O rich glassy slag. Studies of thin sections of the slag products were shown to be very useful in separating amorphous phases such as the K₂O rich glass from the crystalline olivine rim.     

25—THE DETERMINATION OF PENTACHLOROPHENYL LAURATE IN TEXTILE AND PAPER MATERIALS

Methods for the quantitative determination of pentachlorophenyl laurate (L.P.C.P.) in textile materials, described in British Standard 2087 and elsewhere, are reviewed, and it is demonstrated that a closer control of the quantities of added reagents is necessary. A modification in this respect to the existing British Standard method is proposed.

A further modification is proposed whereby the existing 2-hr boiling with 4N aqueous sodium hydroxide is replaced by boiling for 30 min with an ethylene glycol solution of sodium hydroxide. This modification gives good recovery of L.P.C.P. for materials containing components such as wax or elastomers, for which low recovery had previously been obtained, and, in addition, considerably shortens the time of the determination.