Document NGB9XOpYwr2ybRp1DnjY8a2Qp

FILE NAME: RT Vanderbilt (RTV) DATE: 1970 Mar 19 DOC#: RTV310 DOCUMENT DESCRIPTION: Memo RE Photomicrographs of WESTAL 101,201,301,303,401-404 & VANSIL OFFICE M E M O II DATE: March 19, 1970 TO: Mr, R, C. Bacon FROM: Dr, R. M. Husband SUBJECT: Photomicrographs o f UESTAL 101, 201, 301, 303, 401 - 404, & VANS1L MG. Here are the electron-photom icrographs from Ernest F . Fullam , I n c ., and some l i g h t photomicrographs made by Mr, E , S la v so n in cur la b o ra to ry . Their d is p a tc h to you has been delayed by a problem th a t has taken Sln-.;son away from the la b during several recent days. You w ill observe th a t the lig h t photomicrographs are not properly in foce T h is stem s, I b e lie v e , from the lim it a t io n s o f our most ela mentary equip.'.ont and Slaw son' s lim ite d e x p erie n ce. However, I th in k they a rc sui f i c i e r . t to g iv e some b e t t e r view o f the range o f p a r t ic le sin.es v i t h i n one so.::pi seme comparison o f th e d iffe r e n t sam ples. Mote th a t they m agnify the p a r ti :le s 9S0 tin . Each o f the e le c tr o n micrographs shows the presence o f la rg e ir r e g u la r ly shaped p a r t ic le s (up to 21/i or so in a t le a s t one dimension) which are probably m u lti.-p la te (m u lti-la y e r ) p a r t i c l e s . Each a ls o shows the presence o f many Lain tr a n s lu c e n t to tran sp arent p la te s ranging in s i z e from about 5pu 7/idowt\ to m inute specs about 0 .J, sq u a re , Some p a r t ic le s in d ic a t e ir r e g u la r fr a c tu r in g o f d i f f e r e n t la y e r s o f m u ltila y e r p a r t ic le s (see p a r t i c l e A,--T alc E , T alc F .) w hich may be illu s t r a t e d in th is way; There are many p la c e s where th in p la te s may be seen o v e rly in g other th in p la t e s , p a r t i a l l y or w h o lly , in such a manner th a t i t i s easy to th ink they are r.ot attached to each other. Each sample shows soma amount o f m a te r ia l i n the form o f r e l a t iv e l y th in rod-shaped p a r t i c l e s . Though some o f th ese rods may be narrow s liv e r s broken from m u lt i- p la t e p a r t i c l e s , some do not appear to f i t such a d e sc rip tio n and may be a fib r o u s form o f t a lc or some other m in e ra l. Note e s p e c ia lly the two lig h t micro grap hs o f VANSIL MG, The one narked `'Normal F ie ld " i s the vievj a t the cen ter o f a smear formed from VANSIL MG suspended in a lc o h o l. The other shows the view at the edge o f the smear where many rods a re c lu s te r e d together because th e ir in t e r r e la tio n s to the suspending alcohol d iffe re d from those o f the other p a r tic le s . FosVan00110 2. The lig h t micrographs reveal that the more coarsely ground products c o n ta in a greater proportion o f larger p a r tic le s than do the finer grinds - V:STAlP 401 - 404 ^VidlSilP 11G. And the electron micrographs emphasise the g r e a t range o f p a r tic le c i z s c even though they exclude the largest cisco . C o nsid erin g the ranges o f p a r t i c le s i r e ':, I an forced to wonder the follow ing: 1. How do the sp e c tra o f p a r t i c le s ic e s change with the g rin d in g and s e p a r a to r y nodes? Do the p ic tu r e s o f U iSlVdP 401 - 404 and o f VAhSIiP AG compare d i f f e r i n g g rin d in g and sep arato ry procedures on the scree ores or on d iff e r e n t o r e s ? O r, do they re v e a l the r e s u lt o f d i f f e r i n g p rocessing, modes on d iff e r e n t o r e s? I t should be re v e a lin g to fo llo w the change in p a r tic le s ir e d is tr ib u tio n s d u r in g f lu id energy m illin g compared t o , say, mechanical impact m illin g . 2. What are the r e la t io n s o f other supposedly e v a lu a tiv e measure.'.ents and o f the u t i l i t i e s o f the products to the spectra of p a rticle s ic e s .' 1 suspect th a t VAl.SiL-' MG would serve the b e tte r in TiOg e x te n sio n , the le s s the in cid en ce o f t h ic k or m u lti-p la te p a r t ic le s and the store uniform and s c a lie r the p la te s ir .e o -60 lo n g as they were not reduced below sca-e unknown minimal s ic e which e ig h t be of the order o f 0 .5 / i^ . Indeed, va are examining the re la tio n s involved in the e x te n s io n o f Tido w ith VADSIlP LG and m y be a b le to pas3 b e tte r opinion about th is point before long.* For use as a paper f i l l e r , there might be no v ir tu e in u n ifo rm ity o f p a r t ic le s ix e . A range o f s ir e s n ight serve the b e tte r, perchance. Some people are q u ite s k e p t ic a l o f the rep resen ta tio n of p a r t ic le s i z e d is t r ib u t io n s provided by the common sedim entation techniques upon coma m a te r ia ls such as ta lC 6 . These p ic tu r e s would probably re in fo rce th e ii skepticism . L ik e w ise , i t i s easy to assume th at other end uses n ig h t be served the b e tte r or poorer v ith change o f p a r tic le s ir e distribution^ Of course, I f th e r e i s no convenient and economic way to change the d is t r ib u t io n s , the q u estio n s and assum ption i s ir r e le v a n t ; but i t would bs nave that su rp risin g i f the p r a c t ic a l u t i l i t i e s o f products could not be r e la te d , with study, to si.;es of the p a r tic le s and th e ir chem ical c h a r a c te r is tic s , * F .e a lla e ta c t each lar^ e m u lti-la y e re d p a r t ic le could provide many sm all and th in p l a t e l e t s , each o f whicn could serve to separate Ti02 p a r t ic le s . I t is in th is way too th a t a ta lc th at can be e x te n s iv e ly taken apart in to sm all p la te le ts can have a v e ry much la rg e r su rfa c e area per u n it weight* Pd-hl: amt enc. c c / U r . H. W. Howard, RMll-WLC FosVan00111