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BACKGROUND OF THE INVENTION' L i t h i u mm e t a l h a s m a n y u s e s a n d , t o n a m e a f e w , t h e y

i n c l u d e n u c l e a rpower a p p l i c a t i o n where a b l a n k e t o ft h e l i q u i dm e t a l o r i t s m o l t e n s a l t si s u s e d f o r b r e e d i n gp u r p o s e s i n n u c l e a r f u s i o n r e a c t o r s , i n l i g h t w e i g h t ,compact l i t h i u m / s u l f u r b a t t e r i e s f o r e l e c t r i c c a r s a n df o r power p l a n t l o a d l e v e l i n g p u r p o s e s , a s a d e g a s i ? e ri nt h e p r o d u c t i o n o fh i g h - c o n d u c t i v i t yc o p p e r a n db r o n z e ,a n d i n t h e s y n t h e s i s o f compounds f o r u s e i n t h e ? e l d o fmedicine.

L i t h i u mm e t a l i s g e n e r a l l yp r o d u c e db y e l e c t r o l y s i so f e u t e c t i c m i x t u r eo f h i g h l y p u r e m o l t e n l i t h i u m c h l or i d e and p o t a s s i u m c h l o r i d e .

T h e r e a r e n a t u r a l l y o c c u r r i n gb r i n e s i n t h e U n i t e dS t a t e s which c o n t a i n r e a s o n a b l e c o n c e n t r a t i o n so f l i t hi u m , i n t h e form o f t h e c h l o r i d e , s o a s t o be c o n s i d e r e dv i a b l e r e s e r v e s f o r l i t h i u m r e c o v e r y . Three p a r t i c u l a rs o u r c e s i n c l u d eS e a r l e s L a k e , C a l i f o r n i a , t h e G r e a t S a l tL a k e , U t a h ,a n d C l a y t o nVa l l e y , N e v a d a .The l a t t e ri st h e most economical s o u r c e o fl i t h i u m s i n c e t h e m a g n es i u m t o l i t h i u m r a t i oi s l o w , g e n e r a l l y a b o u t 1 . 1 5 : 1 ,which a l l o w s f o r a s i m p l i ? e dp r o c e s s o f c o n c e n t r a t i n g ,p u r i f y i n ga n d r e c o v e r i n gl i t h i u m c h l o r i d e b r i n e .L i t hium c a r b o n a t ei s t h e n o b t a i n e db y t r e a t m e n t o ft h e b r i n ew i t h s o d a a s h .

To make l i t h i u m m et a l , t h e l i t h i u mc a r b o n a t ei s conv e r t e d t o l i t h i u m h y d r o x i d ev i a a l i m i n g p r o c e s s , andt h e l a t t e rc o m p o u n d i n t u r n i s converted t o l i t h i u mc h l o r i d eby t r e a t m e n tw i t h h y d r o c h l o r i ca c i d f o l l o w i n gb y d r y i n g . T h i s i s a v e r y c i r c u i t o u s and e x p e n s i v er o u t et o l i t h i u m c h l o r i d e , s i n c e l i t h i u m o r i g i n a l l y e x i s t sa s t h ec h l o r i d ei n t h e n a t u r a l b r i n e . T h u s , f o r many y e a r s t h e r eh a s been t h e need f o r a d i r e c t economical me thod f o rr e c o v e r i n gl i t h i u m c h l o r i d ea s s u c h from n a t u r a l b r i n e s .

As n o t e d , n a t u r a l b r i n et y p i c a l l y c o n t a i n so n l y a f e wh u n d r e dp a r t s p e r m i l l i o n o f l i t h i u m i n c o n j u n c t i o nw i t hs u b s t a n t i a lq u a n t i t i e so f s o d i u m , p o t a s s i u ma n d magnesium c h l o r i d e s a nd s u l f a t e s , a s w e l l a s o t h e r minor cont a m i n a n t s s u c h a s b r o m i d e s ,r u b i d i u m ,boron and o rg a n i c c o m p o u n d s .I n t h e m a n u f a c t u r eo f l i t h i u m m e t a lb y e l e c t r o l y s i so f l i t h i u m c h l o r i d e , t h e a l k a l i n ee a r t hm e t a l s must ? r s t b e removed from t h e l i t h i u m c h l o r i d e ,o t h e r w i s e t h e y w i l l ' b e p r e s e n t a s c o n t a m i n a n t si n t h el i t h i u m m e t a l . S i m i l a r l y , s o d i u m m u s tb e removed s i n c et h e p r e s e n c eo f v e r y s m a l l q u a n t i t i e s t h e r e o f i n t h e l i t hium m e t a l w i l l make t h i g h l y r e a c t i v e a n d m u c h i f f e re n t i n p r o p e r t i e s t h a n h i g h p u r i t y l i t h i u m m e t a l . A l s o ,d u r i n gt h e e l e c t r o l y s i so f l i t h i u m c h l o r i d e ,n o n - v o l a t i l ea n i o n s , s u c h a s s u l f a t ea n d b o r a t e , w i l l b u i l d u p r e s u l t i n gi n v e r y r a p i d s h o r t c i r c u i t i n g o f t h e c e l l .S i n c ec e l lc o s t sa r e q u i t eh i g h ,c o n t i n u o u s u n i n t e r r u p t e d o p e r a t i o nt h e r e o f f o r e x t e n d e dp e r i o d s o f t i m e , eg i x months t oa y e a r , m u s t b e r e a l i z e d .

I t i s a p r i m a r yo b j e c t o f t h i s i n v e n t i o nt o p r o v i d ea ni m p r o v e dp r o c e s s f o r p r o d u c i n gl i t h i u m ,c h l o r i d e o fh i g h p u r i t y .

Another o b j e c t o f h i si n v e n t i o n i s t o p r o v i d ea n o v e lmethod f o r t r e a t i n g l i t h i u m c h l o r i d e t o i m p r o v e t h e? l t e r a b i l i t yo f s o l v e n t s o l u t i o n s t h e r e o f w h e r e b y ,t h eamounts o f s u c h c o n t a m i n a n t sa s s o d i u m ,a l k a l i n e e a r t hm e t a l s , b o r o n a n d o r g a n i c s may b e r e d u c e dt o s u c h

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2a sa n e l e c t r o l y t e i nt h e p r o d u c t i o n o f h i g hp u r i t y l i t h i u mmetal. , I I . .

O t h e r o b j e c t sa n d a d v a n t a g e so f h ep r e s e n t i n v e n t i o nw i l lb e c o m ea p p a r e n t f r o mt h ef o l l o w i n gd e s c r i p t i o no fs p e c i ? ce m b o d i m e n t st h e r e o f a n d t h ea p p e n d e dc l a i m s .

DETAILED DESCRIPTION OF THEINVENT IO N

A c c o r d i n gt o t h i si n v e n t i o nt h e r e i s p r o v i d e da n o v e lp r o c e s s f o rp u r i f y i n gl i t h i u m c h l o r i d e c o n t a i n i n gs m a l la m o u n t so f v a r i o u s i m p u r i t i e s s u c h a s s o d i u m , p o t a ss i u m , c a l c i u m , b o r o n ,s u l f a t ea n d / o r o r g a n i c s w h i c hc o m p r i s e sh e a t i n g l i t h i u m c h l o r i d e c o n t a m i n a t e dw i t ho n e or m o r e of s a i d i m p u r i t i e s t o a t empera tu re ab o v ea b o u t 2 0 0 C . b u t n o t s u b s t a n t i a l l y e x c e e d i n gt h e m e l ti n g p o i n t o f l i t h i u m c h l o r i d e ,c o o l i n gt h e l i t h i u m c h l or i d e t o a m b i e n tc o n d i t i o n s , e x t r a c t i n g t h e l i t h i u m c h l or i d ew i t h i s o p r o p a n o l , s e p a r a t i n g t h el i q u i dp h a s e f r o mt h e s o l i dp h a s e , r e m o v i n gt h e i s o p r o p a n o l ,a n d r e c o v e ri n g a s o l i dl i t h i u m c h l o r i d e p r o d u c to f h i g h p u r i t y .

The s o l i d i m p u r e l i t h i u m c h l o r i d e which may b e

t r e a t e d a c c o r d i n gt o t h i s i n v e n t i o n may b e from a n ya v a i l a b l e s o u r c e . However, f o r t h e s a k e o f c o n v e n i e n c eo f d i s c u s s i o n , t h e p r o c e s s o f t h i si n v e n t i o n i s d e s c r i b e di n c o n n e c t i o n w i t hl i t h i u m c h l o r i d e produced by conc e n t r a t i n g a n a t u r a l b r i n e by means o f s o l a r evaporation . , -

As d e s c r i b e d h e r e i n a b o v e ,by means o f s o l a r e v a p o r at i o n a b r i n e c o n t a i n i n ga b o u t 3 l i t h i u m chloridecanb e o b t a i n e d from a n a t u r a l b r i n e a v a i l a b l e a t C l a y t o nVa l l e y , N e v a d a .T y p i c a l o ft h e c o m p o s i t i o nf o r a b r i n es o c o n c e n t r a t e di s s e t f o r t h i n Table 1 , below.

= TABLE

C o n s t i t u e n t Weight P e r c e n t

L i 0 . 7 7 ( 4 . 7 L i C l )Na 6 .2 8 ,

K 4 . 7 0M g 0 . 0 0 5 3Ca 0 . 0 0 8 1B 0 . 2 6S04 2 .90C l 1 5 . 9 5Br 0 . 0 5 5H2O 6 8 . 8

Su ch b r i n e s t y p i c a l l y have a pH o f a b o u t 9 . 5 a n d as p e c i ? c g r a v i t y of about 1 . 2 5 a t 2 3 C .

A r i n e o f t h e c o m p o s i t i o no f t h a t g i v e n i n T a b l e Imay be f u r t h e r e v a p o r a t e db y s o l a r e n e r g yi n a s u i t a b l ep o n d s y s t e m composed o f a s e r i e so f c o n n e c t e dp o n d so f r e l a t i v e l y l a r g e s u r f a c e a r e a a n d s h a l l o w d e p t h . I nview o f t h e s u b s t a n t i a l e c o n o m i e st o b e e f f e c t e d by t h eu s e o f s o l a r energy t o f u r t h e r c o n c e n t r a t e t h e b r i n e ,

such procedure p r e f e r a b l y i s c a r r i e d out u n t i l a b r i n e

6 0

6 5

l e v e l s a s t o r e n d e r t h e l i t h i u m c h l o r i d e s u i t a b l e f o r u s e

c o n t a i n i n g i n e x c e s s o f 40 l i t h i u m c h l o r i d e i s obt a i n e d .S u c hs o l a re v a p o r a t i o np r o c e d u r es d e s c r i b e di nd e t a i l i nc o p e n d i n ga p p l i c a t i o n S e r .N o . 0 2 8 , 9 7 6 ? l e dA p r . 1 1 ,1 9 7 9 .

B r i e ? y ,t h e p r o c e s s o f .s u c h c o p e n d i n ga p p l i c a t i o nc o m p r i s e s p r o v i d i n ga pond s y s t e mc o n s i s t i n go f a s e r i e so f s h a l l o w p o n d s o f r e l a t i v e l yl a r g es u r f a c e a r e a ,a n d?owing a d i l u t e l i t h i u m c h l o r i d e b r i n e , t h a t o f T a b l e Ib e i n gt y p i c a l ,i n t o o n e e n do f t h e pond s y s t e m . The a t eo f f l o w o f t h e l i t h i u m c h l o r i d eb r i n e t h r o u g ht h e p o n ds y s t e m ,i s r e g u l a t e d s o t h a t t h r o u g h e v a p o r a t i o n b ymeans o f s o l a r e n e r g y , t h e c o n c e n t r a t i o no f t h e b r i n e , a ta p o i n t i n t e r m e d i a t et h e p o i n t s o f i n t r o d u c t i o nt o a n dr e m o v a lo f t h eb r i n e f r o m t h ep o n ds y s t e m , i s i n c r e a s e d


5/7

4 , 2 7 4 , 8 3 4

t o provide a b r i n e w h o s e concentra t ion h a s a v ap o rp r e s s u r e s u b s t a n t i a l l yi n e q u i l i b r i u m w i t h t h e p a r t i a lp r e s s u r e o f m o i s t u r e i n t h e atmosphere a t t h e geog r a p h i c l o c a t i o n o f t h e pond s y s t e m . The c o n t i n u e df l o w o f t h e more c o n c e n t r a t e d b r i n e through t h e r em a i n d e ro f t h e pond s y s t e mi s f u r t h e r r e g u l a t e d s o t h a tt h r o u g h s o l a r e n e r g y t h e t e m p e r a t u r eo f t h e b r i n e d u ri n g a t l e a s t a s u b s t a n t i a l p o r t i o n of t h e d a y l i g h t hoursexceeds t h a t o f t h e a i r immediately ab o v e t h e p o n ds y s t e m . I n t h i s w a y t h e va po r p r e s s u r e of t h e b r i n ee x c e e d s t h e p a r t i a lp r e s s u r e o f m o i s t u r e i n t h e atmos p h e r e a b o v e t h e pond s y s t e m a n d a d d i t i o n a l w a t e r i se v a p o r a t e d t o i n c r e a s e t h e c o n c e n t r a t i o n o f l i t h i u mchloride i n t h e b r i n e t o 40 or more. A r i n e s a t u r a t e dwith r e s p e c t t o l i t h i u m c h l o r i d e can be ob ta ined i n t h i smanner f so desired.

After t h e b r i n e has b e e n concentrated t o t h e d e s i r e dd e g r e e by s o l a r e v a p o r a t i o n , i t i s s u b j e c t e d t o a l i q u i ds o l i d s s e p a r a t i o n s t e p ,e . g . c e n t r i f u g a t i o n o r ? l t r a t i o n ,a n d t h e l i q u i dp h a s e i s t h e n s u b j e c t e d t o e v a p o r a t i o n ,p r e f e r a b l y u n d er v a c u u m t o o b t a i n s o l i d l i t h i u m chlo

r i d e which i s d r i e d . Drying t e m p e r a t u r e s i n e x c e s s o f1 0 1 C . , an d p r e f e r a b l y on t h e order of abou t 1 1 0 C .s h o u l d b e u s e d i n o r d e r t o o b t a i n anhydrous l i t h i u mc h l o r i d e , r a t h e r t h a n t h e m o n o h y d r a t e .

Of c o u r s e , t h e b r i n e can b e concentrated u s i n g anys u i t a b l e energy s o u r c e , e . g . f o s s i lf u e l s , n a t u r a l g a s , e t c . ,bu t t h e e c o n o m i c bene?ts t o b e derived f rom t h e u s e ofs o l a r e n e rg y are obvious.

I n t h e c a s e of d i l u t e l i t h i u m c h l o r i d e b r i n e s having acomposition s i m i l a r t o t h e b r i n e o f Table I i e a b r i n ec o n t a i n i n g s m a l l amounts o f a l k a l i n e e a r t h m e t a l s , b or a t e a n d s u l f a t e , i t m a y b e d e s i r a b l e t o s u b j e c t t h e b r i n et o a c h e m i c a l t r e a tmen t o r t reatments prior to c o n c e nt r a t i o n o f t h e b r i n e . A a r t i c u l a r l y a d v a n t a g e o u sp r oc e s s f o r such purpose i s d e s c r i b e d a n d claimed i n cop e n d i n g a p p l i c a t i o n S e r . N o . 0 2 8 , 9 7 5 ? l e d A p r . 1 1 ,1 9 7 9 . According t o t h e p r o c e s s o f t h a t a p p l i c a t i o n ,calcium c h l o r i d ea nd s l a k e d l i m e a r e a d d e d t o t h e d i l u t eb r i n e c o n t a i n i n ga b o u t 3 i t h i u m c h l o r i d e b e f o r e f u rt h e r s o l a r e v a p o r a t i o n f o r removal o f s u l f a t e ,magnes i u m , a n d b o r o ni m p u r i t i e s .

As i n d i c a t e d a b o v e , t h e s o l i d l i t h i u m c h l o r i d e recovered f rom t h e concentrated b r i n e should b e d r i e d a tt e m p e r a t u r e s s u f ? c i e n t l y h i g h t o p r o d u c e a n h y d r o u sl i t h i u m c h l o r i d e , a s compared t o t h e monohydrate.According t o t h e p r o c e s s o f t h e p r e s e n t i n v e n t i o n t h es o l i d l i t h i u m c h l o r i d eshould b e hea ted t o a temperatureo f a t l e a s t 2 0 0 C . , b u t g e n e r a l l y a t e m p e r a t u r en o t s u bs t a n t i a l l ye x c e e d i n gt h e m e l t i n gp o i n t o f t h e compound

w h ich s abaou t 6 1 3 C . Accord ing t o a p r e f e r r e d proced u r e , t h e b r i n e which h a s b e e n c o n c e n t r a t e db y s o l a re v a p o r a t i o n i s s u b j e c t e d t o e v a p o r a t i o n a t a temperat u r e a b o v ea b o u t 1 0 1 C . ,by a p p l i c a t i o n o f h e a t ,p r e f e ra b l y u n d er v a c u u m t o gene ra te a s l u r r y containing ont h e o r d e r o f 35 by w e i g h t o f s o l i d s .The s o l i d s mayt h e n b e s e p a r a t e d f r o m t h e l i q u i d p h a s e by ? l t r a t i o n o rc e n t r i f u g a t i o n w h i l e t h e t e m p e r a t u r e o f t h e s l u r r y i nmaintained i n e x c e s s of about 1 0 1 C . T h e s o l i d s maythen be introduced t o a s u i t a b l e d r i e r , e . g . of t h e r o t a r yt y p e , w h e r e they a r e heated a t a t empera ture i n e x c e s so f 2 0 0 C . , and p r e f e r a b l y be twe e n a b o u t 2 7 0 and 3 2 5 C . f o r a p e r i o d s u f ? c i e n t t o reduce t h e moisture c o n t e n tt o l e s st h a n abou t 0.5 .

The h e a t i n g o f t h e l i t h i u m c h l o r i d e t o t e m p e r a t u r e sa bove a b o u t 2 0 0 C .produces c e r t a i n b e n e ? c i a l r e s u l t s .Organic contaminants a r e v a p o r i z e d , pyrolyzed o r a tl e a s t r e n d e r e d i n s o l u b l e i n i s o p r o p a n o l , t h e s e l e c t i v e

2 0

2 5

30

3 5

40

4 5

5 5

60

6 5

s o l v e n t f o r l i t h i u m c h l o r i d e u s e d i n t h e p r e s e n t p r o c e s s ,a nd t h e r e b y a r e removed. I n a d d i t i o n , b o r a t e s p r e s e n t ,whic h a l s o a r e s o l u b l e i n i s o p r o p a n o l , a r e conver ted t oboron o x i d e w h ich i s i n s o l u b l e i n t h i ss o l v e n t and t h u st h e p o s s i b i l i t yo f t h e l i t h i u m c h l o r i d e b e i n g c o n t a m in a t e d w i t h amounts o f boron u n a c c e p t a b l ef o r manyp u r p o s e s i s g r e a t l y d e c r e a s e d .

T h e l i t h i u m chlor ide i s subsequent ly cooled t o am b ie n t temperatures a n d e x t r a c t e d with i s o p r o p a n o l . Thea m o u n t o f i s o p r o p a n o l u s e d s h o u l d be such t h a t t h ew e i g h t r a t i oo f i s o p r o p a n ol t o s a l t t o b e e x t r a c t e d i sfrom a b o u t 5 : 1t o a b o u t 1 0 : 1 ,a w e i g h t r a t i o o f a b o u t 7 : 1b e i n gp r e f e r r e d .

T h e e x t r a c t i o n s t e pm a y be c a r r i e d o u t under ambientt e m p e r a t u r ec o n d i t i o n s ; h o w e v e r ,t e m p e r a t u r e s i n t h eo r d e r o f 2 0 C . u p t o 8 3 C . , t h e b o i l i n g p o i n t o f i s o p r op a n o l , may b e u s e d . Employing e x t r a c t i o n t e m p e r a t u r e sof 8 3 C . or more would , of c o u r s e , r e s u l t i n l o s s ofs o l v e n t t h r o u g hv o l a t i l i z a t i o n .

The e x t r a c t i o n t i m e may v a r y c o n s i d e r a b l y ,e . g .from1 t o 24 h o u r s , d ep en d i n g u p o n t h e s i z e o f t h e l i t h i u mc h l o r i d e ( s a l t )p a r t i c l e s ,a g i t a t i o n r a t e a n d s o l v e n t t e mp e r a t u r e . G e n e r a l l y good r e s u l t s c a n b e o b t a i n e d b ys l u r r y i n g t h e s a l ti n t h e i s o p r o p a n o lw i t h g o o da g i t a t i o nf o r a p e r i o d o f abou t 3 h o u r s .

The i s o p r o p a n o l - s a l t s l u r r y i s n e x t s u b j e c t e d t o al i q u i d - s o l i d s s e p a r a t i o n , a s f o r e x a m p l e b y ? l t r a t i o n .The ? l t e r a b i l i t y o f t h e s l u r r y a n d r a t e o f s e p a r a t i o n o fs o l i d s from t h e l i q u i d a r e dependent u p o n d r y i n g temp e r a t u r e s o f l i t h i u m c h l o r i d ea s d e s c r i b e d h e r e i n a b o v ean d i n c e r t a i n o f t h e s u b s e q u e n t e x a m p l es .

The d e g r e e o f s e p a r a t i o n , i . e . t h e r e m o v a l o f s o l i d sfrom t h e l i q u i d p h a s e i s d e p e n d e n tupon t h e d e s i r e du t i l i t yf o r t h e l i t h i u m c h l o r i d e p r o d u c e d .

I n o b t a i n i n ga l i t h i u m c h l o r i d eproduct o f low sodium

a n d boron content f o r u s e a s a n e l e c t r o l y t e f o r t h e prod u c t i o n o f h i g hp u r i t y l i t h i u m m e t a l , i t i s d e s i r a b l e t h a tt h e ? l t r a t e have a Nephlometric T u r b i d i t y o fl e s st h a nabout 3 . This w i l l i n s u r e t h a t t h e sod ium l e v e l i s l e s st h a n a b o u t 5 0p p m. Su ch r e s u l t can be accomplished by? l t e r i n g t h e l i q u i dp h a s e s e v e r a lt i m e s t h r o u g hs u i t a b l e? l t e r m e d i a . For e x a m p l e ,t h e l i q u i d p h a s e c a nb e t w i c e? l t e r e d through a D o r o s i t y ? l t e r , t h e second ? l t r a t i o nb e i n g c a r r i e d o u t through t h e wet ? l t e r cake o f t h eprimary ? l t r a t i o n . E v e n lower l e v e l s o f sodium can b eo b t a i n e d b y u s e o f very ? n e , such a s 0 . 4 5 um i l l i p o r e ,? l t e r s .

FIG. 1 h e r e t o i s a p l o t o f sod ium i n p a r t s p e r m i l l i o ni n t h e l i t h i u m c h l o r i d e product v e r s u s t u r b i d i t y , me as u r e d i n Nephlometric T u r b i d i t y U n i t s . The d a t a u s e dt o p l o t t h e graph o f FIG. 1 was o b t a i n e d u s i n g a F i s h e rDRT-l00 Turbidimeter. As can b e seen b y reference t oFIG. 1 , t o o b t a i n a l i t h i u m c h l o r i d e p r o d u c tc o n t a i n i n gl e s s t h a n 5 0 ppm o d i u m , t h e t u r b i d i t y s h o u l d n o t s u bs t n t i l l ye x c e e d a b o u t3 .

F o l l o w i n gt h e l i q u i d - s o l i d ss e p a r a t i o n s t e p ,t h e i s op r o p a n o li s r e m o v e d ,p r e f e r a b l yb y h e a t i n g t h e s o l u t i o no f l i t h i u m c h l o r i d e i n i s o p r o p a n o l u n d e r a t m o s p h e r i cp r e s s u r e a nd a t modera te t e m p e r a t u r e s , e . g . abou t 9 0 C . , f o l l o w e db y r e m o v i n ga n y r e m a i n i n gs o l v e n t u n d e rv a c u u m a t r e d u c e d t empera tu re s t o preven t ove rhea ti n g o f t h e p r o d u c ta n d s o l v e n t d e g r e d a t i o n .The i s o p r op a n o l can be recovered a n d r e c y c l e d t o t h e s o l v e n te x t r a c t i o n s t e p ,a n d d r y l i t h i u m c h l o r i d eo f h i g h p u r i t yr e c o v e r e d .

The anhydrous l i t h i u m c h l o r i d e o b t a i n e d a s h e r e i ndescr ibed ? nd s p a r t i c u l a r u s e a s an e l e c t r o l y t e i n t h e


6/7

. 5 ' v

p r o d u c t i o n o fl i t h i u m m e t a l w h o s e .v a r i o u s u s e s h a v ebeen escribedfabove. I

T h e f o l l o w i n gn o n - l i m i t i n ge x a m p l e sa r e g i v e n b yway of e x p l a n a t i o n . , i . I

EXAMPLE

A a t u r a l l y o c c u r r i n gb r i n e was p u m p e d f r o m t h e

g r o u n da t C l a y t o n Va l l e y ,N e v. , a n d e v a p o r a t e db ymeans o f s o l a r e n e r g yt o 1 5 0 0p p m l i t h i u m a c c o r d i n gt ot h e c o m m e r c i a lp r o c e s s o f F o o t e M i n e r a l Companyp r e v i o u s l y d e s c r i b e d . The b r i n e was t h e n l i m e d f o rm a g n e s i u mr e m o v a l a n df u r t h e r c o n c e n t r a t e db y s o l a re n e r g yt o a b o u t 0.6 l i t h i u m ( a b o u t 3.6 l i t h i u m c h l or i d e ) . .

A p p r o x i m a t e l y1 , 4 5 7g a l l o n s ( 1 4 , 5 6 3p o u n d s )o f t h i smore c o n c e n t r a t e db r i n e was t r e a t e d with 0 . 0 5 8 poundso f l i m e a n d 0 . 8 1 2p o u n d so f c a l c i u mc h l o r i d ep e r poundo f l i t h i u m c h l o r i d e i n t h e b r i n e a c c o r d i n gt o t h e pr o c e s so f c o p e n d i n ga p p l i c a t i o n S e r .N o . 0 2 8 , 9 7 5? l e d A p r . 1 1 ,1 9 7 9 . The r e s u l t a n t s l u r r y was a l l o w e dt o s e t t l e ,and t h es o l i d s - f r e e l i q u i d was d e c a n t e dt o produce a b r i n e y i e l d

o f a b o u t 9 2 . 4 .1 1 , 9 8 4 Pounds o f t h e p u r i ? e d b r i n e were p l a c e d i ntwo e v a p o r a t i n gp a n s and were e v a p o r a t e dby means o fs o l a r e n e r g yi n a s e r i e s o f f o u r s t e p s .A f t e r s t a n d i n g f o ra p e r i o d o f t i m e , a p o r t i o n o f t h e b r i n e p r e c i p i t a t e d a sc a l c i u mb o r a t e h y d r a t e . The o m p o s i t i o n o ft h e p u r i ? e db r i n e p r i o r t o , d u r i n g a n d a t t h e c o n c l u s i o no f t h e l a s td e s c r i b e ds o l a r e v a p o r a t i o ni s s e t f o r t h i n T a b l e 1 1b elow. .

TABLE I

4 , 2 7 4 , 8 3 4

2 5

3 0

6c h l o r i d e p r o d u c t w e i g h e d4 2 . 6 g r a m s a n d h a dt h e f o ll o w i n g a n a l y s i s :

TABLE IVConst i tuen t We i g h t Percent or PPM

Li 16 . 24

Na 0 . 0 0 2 2K 0 . 0 0 6 0

F e 2 O 3 0 . 0 0 2C l 8 2 . 9 4B 0 . 0 0 1 51 1 2 0 0 . 0 9 4Li2CO3 0 . 0 7B a C l z 3 p p mC a C l ; 0 . 0 0 5 5S04 0 . 0 1 5

As c a n b e s e e n b y r e f e r e n c e t o T a b l e I V, t h e l i t h i u mc h l o r i d e p r o d u c t s o g e n e r a t e dwas r e l a t i v e l y p u r e .

EXAMPLE

The p r o c e d u r e o fExample 1 was r e p e a t e d w i t h t h ee x c e p t i o nt h a t3 6 . 9g r a m s ' o ft h e i m p u r el i t h i u m c h l o

r i d e ,p r i o r t o e x t r a c t i o n w i t h i s o p r o p a n o l ,were h e a t e dt o 2 7 0 C . and t h e n e x t r a c t e d , i . e . s l u r r e d w i t h 2 6 9 . 4grams o f i s o p r o p a n o lo v e r a p e r i o d o f 2 4 h o u r s . Thes l u r r yw a s t h e n ? l t e r e d t h r o u g h aD o r o s i t y f r i t t e d? l t e r a n d t h e n t h r o u g h a 0 . 4 5 m i c r o m e t e rm i l l i p o r e? l t e r .The s o l v e n t was e v a p o r a t e d o f f r e s u l ti n g i n al i t h i u mc h l o r i d ep r o d u c t h a v i n gt h ef o l l o w i n ga n a l y s i s .

ANALYTICAL RESULTS OF BRINE COMPOSITIONSFROM SOLAR EVAPORATION

W e i g h t E x c e p t a s N o t e d )K . F .

, - > 1L i Mg Na Ca K 504 B c1 H2O Al LiOl- l Li2CO3

o r i g i n a ' i l a n n 0 . 4 4 9


7/7

4 , 2 7 4 , 8 3 47

s o l v e n t ( i s o p r o p a n o l ) w as r emo v ed an d i t s p r o d u c t sd r i e d . The m a j o r i m p u r i t i e s i n t h e s o l i d p r o d u c t sf o r t h ev a r i o u s s o l v e n t / s a l t r a t i o s a r e g i v e n i n Table V I .

TABLE VI

M a j o r I m p u r i t i e si n S o l i d P r o d u c t sfrom V a r i o u s S o l v e n t / S a l t R a t i o s

PPm PPm

R u n R a t i o Na p p m Ca p p m S04 p p m B % 2OK

1 1 0 . 0 / ] 4 3 4 5 28 l l 2 0 . 3

2 7 . 3 / 1 24 3 6 2 ] l 4 7 0 . 1

3 6.4/1 1 8 47 1 9 l l - 0 . 1

4 5 . 5 / 1 2 1 3 5 1 7 l l 4 0 . 2

5 5 .0 /1 19 36 O.l

EXAMPLE 4

T h i s example shows t h e e f f e c t o f t h e t e m p e r a t u r e su s e d i n drying t h e l i t h i u m c h l o r i d eon t h e ? l t r a t i o n r a t e

of a n i s o p r o p an o le x t r a c t of t h e crude s a l t .C rude s a l t whic h wa s white i n c o l o r wa s o b t a i n e d b y

d r y i n g t h e s a l t from t h e c o n c e n t r a t e a t 1 1 0 C . undervacuum n t i l t h e moisture content of t h e s a l t w a s a b o u t

0 . 5 . The d r i e d s a l twas t h e n ground i n a j a w c r u s h e r .Samples o f t h e ground s a l tw ere f u r t h e r d r i e d a t v a r i

ous t empera tu re s f o r 30 minutes u s i n g a muff l e oven . I n

each i n s t a n c e t h e h e a t u p time wa s 5 m i n u t e s , a nd t h ed r i e d p r o d u c t showed s i g n s o f c h a r r i n g . The s a m p l e swere c o o l e d a n d t h e n e x t r a c t e d w i t h 7 . 3 pounds o fi s o p r o p a n o l p e rpound o f s a l t . The e x t r a c t i o n t i m e i neach i n s t a n c e w a s 24 h o u r s .

The r e s u l t i n gs l u r r i e s

o f s a l t i n i s o p r o p a n o l were? l t e r e d through a D p o r o s i t y f r i t having a p r e c o a t o fK700 ? l t e r a i d under 1 5 Hg r e s s u r e .

Ta b l e VII summar izes ? l t r a t i o n r a t e a s a function of

d r y i n gt e m p e r a t u r e s .TABLE VII

F i l t r a t i o n Rate

Drying 1 s t P ass - 2nd P ass ~

Temp. C . * g . s l u r r y / m i n . g . s l u r r y / m i n .

240 2 . 6 9 2 . 1 0

280 3 . 3 3 3 . 0 5

1 0

2 5

3 5

45

50

5 5

6 5

TABLE I I - c o n t i n u e dF i l t r a t i o n Rate

Drying l s t P ass - 2nd P ass -

Temp. C . * g . s l u r r y / m i n . g . s l u r r y / m i n .

300 4.86 4.25325 1 3 . 5 4 1 0 , 0 8

3 0 m i n . d r y i n gt i m e

I n p r e v i o u s e x p e r i m e n t swhere t h e crude s a l t wasd r i e d a t 1 1 0 C . , ? l t r a t i o n r a t e s we re t e d i o u s l y s l o w ,b e i n g c o n s i d e r a b l ys l o w e r t h a n f o r s a l td r i e d a t 2 7 0 C .

As shown b y T a b l e V I I , t h e h i g h t e m p e r a tu r e d r y i n ga c c o r d i n gt o t h i s i n v e n t i o n p r o v i d e s t h e b e n e ? t o f i nc r e a s i n g t h e r a t e o f ? l t r a t i o n o f t h e i s o p r o p a n o le x t r a c t .

FIG. 2 h e r e t o i s a p l o t o f ? l t r a t i o n r a te o f t h e i s o p r opano l e x t r a c t a s a f u n c t i o n o f drying t e m p e r a t u r e s , an dshows t h a t f o r crude l i t h i u m c h l o r i d e s a l td r i e d a t temp e r a t u r e s a bove a b o u t 3 0 0 C . , t h e ? l t r a t i o n r a t e i nc r e a s e s r a p i d l y ,p a r t i c u l a r l y when d r y i n g t e m p e r a t u r e son t h e orde r o f 325 C. a r e u s e d .

D i f f e r e n t i a l t h e r m a l a n a l y s i s performed on t h e c r u d e

s a l t r e v e a l e d an exotherm a t 3 5 4 C . w h i c h h a s be e na s s i g n e d t o t h e l i t h i u m c h l o r i d e / p o t a s s i u mc h l o r i d ee u t e c t i c m e l t i n g p o i n t .The e l i m i n a t i o n o f ? n e p a r t i c l e so f p o t a s s i u mc h l o r i d e b y h e a t i n g t o e l e v a t e d t e m p e r at u r e s i s b e l i e v e d t o account f o r t h e i n c r e a s e d ? l t e r i n gr a t e s .

I t i s c l a i m e d :1 . A r o c e s s f o r p u r i f y i n gl i t h i u m c h l o r i d e c o n t a i n i n g

s m a l l amounts o f i m p u r i t i e s s u c h a s s o d i u m ,p o t a s s i u m ,c a l c i u m , b o r o n , s u l f a t ea n d / o r o r g a n i c compoundswhich c o m p r i s e sh e a t i n g l i t h i u m c h l o r i d ec o n t a m i n a t e dwith o n e or m o r e of s a i d i m p u r i t i e s t o a t empera tu re i nt h e r a n g e o f from a b o u t 2 7 0 t o a b o u t 3 2 5 C . , c o o l i n gs a i d l i t h i u m c h l o r i d e t o a m b i e n t c o n d i t i o n s , ex t r a c t i n gs a i d l i t h i u m c h l o r i d e w i t h i s o p r o p a n o l , s e p a r a t i n gt h el i q u i dp h a s e f r o m t h e s o l i dp h a s e , r e m o v i n gs a i di s o p r o 'p a n o l f r o m s a i d l i q u i dp h a s e , a n d r e c o v e r i n ga s o l i dl i t h i u m c h l o r i d ep r o d u c t o f h i g h p u r i t y .

2 . The p r o c e s s according t o c l a i m 1 i n w h ich s a i dl i t h i u m c h l o r i d e i s e x t r a c t e d with from abou t 5 t o abou t1 0 p a r t s b y w e i g h to f i s o p r o p a n o l p e rp a r t b y w e i g h to fl i t h i u m c h l o r i d e .

3 . T h e p r o c e s s according t o c l a i m 1 i n whic h t h ei s o p r o p a n o l c o n t a i n i n gd i s s o l v e d l i t h i u m c h l o r i d e i spassed through a very ?n e ? l t e r t o provide a ? l t r a t eh av in g a t u r b i d i t y of l e s s t h a n abou t 3 .

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