Rheological Properties of Molten Kilauea Iki Basalt ... - ACS Publications

17 Rheological Properties of Molten Kilauea Iki Basalt Containing Suspended Crystals H . C . Weed, F. J. Ryerson, and A . J. Piwinskii

Downloaded by TUFTS UNIV on June 12, 2018 | https://pubs.acs.org Publication Date: April 2, 1986 | doi: 10.1021/bk-1986-0301.ch017

University of California, Lawrence Livermore National Laboratory, Livermore, CA 94550

In order to model the flow behavior of molten silicate suspensions such as magmas and slags, the rheological behavior must be known as a function of the concentration of suspended crystals, melt composition, and external conditions. We have determined the viscosity and crystallization sequence for a Kilauea Iki basalt between 1250°C and 1149°C at 100 kPa total pressure and fO corresponding to the quartz-fayalite-magnetite buffer in an iron-saturated Pt30Rh rotating cup. viscometer of the Couette type. The apparent viscosity varies from 9 to 879 Pa.s. The concentration of suspended crystals varies from 18 volume percent at 1250°C to 59 volume percent at 1149°C. The molten silicate suspension shows power-law behavior: 2

log

|τ | yx

= A + A log |du/dx|, o

l

where τ is the shear stress and (du/dx) the shear rate. Since A ≤ 1, the apparent viscosity decreases with increasing shear rate and the system is pseudoplastic. yx

l

In o r d e r t o u n d e r s t a n d the f l o w b e h a v i o r o f m o l t e n s i l i c a t e s c o n t a i n i n g suspended c r y s t a l s , we need t o know t h e r h e o l o g i c a l p r o p e r t i e s o f t h e system as a f u n c t i o n o f volume f r a c t i o n o f t h e suspended c r y s t a l l i n e phases a t a p p r o p r i a t e t e m p e r a t u r e s , oxygen f u g a c i t i e s and m e l t c o m p o s i t i o n s . Because o f t h e w i d e s p r e a d o c c u r e n c e o f s i l i c a t e s , t h i s approach c a n be a p p l i e d t o magma t r a n s p o r t d u r i n g v o l c a n i c e r u p t i o n s , l a r g e s c a l e c o n v e c t i v e and m i x i n g p r o c e s s e s i n magmatic systems, and f o u l i n g o f i n t e r n a l b o i l e r s u r f a c e s by c o a l a s h s l a g s i n p l a n t s b u r n i n g p u l v e r i z e d coal. The f i r s t system we have s t u d i e d i s a b a s a l t i c l a v a from K i l a u e a I k i , H a w a i i , f o r which we have determined t h e c r y s t a l l i z a t i o n sequence and t h e dynamic v i s c o s i t y . 0097-6156/ 86/0301 -0223S06.00/0 © 1986 American Chemical Society

Vorres; Mineral Matter and Ash in Coal ACS Symposium Series; American Chemical Society: Washington, DC, 1986.

224

MINERAL MATTER AND ASH IN COAL

E x p e r i m e n t a l Methods


Starting Material. The s t a r t i n g m a t e r i a l f o r t h e s e experiments i s K i l a u e a I k i b a s a l t fragments which have been ground i n a t u n g s t e n c a r b i d e s h a t t e r b o x t o -100 mesh and homogenized by m i x i n g w i t h a p a d d l e and t h e n t u m b l i n g f o r 1.5 h o u r s . T h i s m a t e r i a l was then f u s e d i n a i r a t 1400°C f o r about 3.3 h o u r s , quenched i n d e i o n i z e d water, r i n s e d w i t h a c e t o n e , and d r i e d under vacuum (15 ym) a t 110°C f o r 70 h o u r s . The d r i e d m a t e r i a l was ground i n a boron c a r b i d e m o r t a r and p e s t l e and s t o r e d i n a screw cap g l a s s b o t t l e b e f o r e use. L i g h t m i c r o s c o p i c e x a m i n a t i o n shows t h a t i t i s c l e a r , f r e e o f opaque i n c l u s i o n s , and i s o t r o p i c under c r o s s e d niçois; i t i s t h e r e f o r e presumed t o be g l a s s . C r y s t a l l i z a t i o n Sequence D e t e r m i n a t i o n . The s t a r t i n g m a t e r i a l f o r the d e t e r m i n a t i o n o f the c r y s t a l l i z a t i o n sequence was the homogenized -100 mesh r o c k powder b e f o r e f u s i o n . Samples were i n the form o f s p h e r i c a l beads suspended by s u r f a c e t e n s i o n i n p l a t i n u m l o o p s as d e s c r i b e d by Grove e t a l . (JL). They were p r e p a r e d by p r e s s i n g about 190 mg o f powder i n t o a c y l i n d r i c a l p e l l e t w i t h two o r t h r e e drops o f e t h a n o l as a b i n d e r . The d i a m e t e r o f the p l a t i n u m w i r e was 0.25 mm and the d i a m e t e r o f t h e l o o p about 3 mm. The p e l l e t was f u s e d t o the l o o p by r e s i s t i v e h e a t i n g o f the p l a t i n u m and t h e n suspended from a p l a t i n u m b r i d g e w i r e by an AI2O3 c o n n e c t o r which i n s u l a t e d i t e l e c t r i c a l l y from the b r i d g e w i r e . The b r i d g e w i r e was c o n n e c t e d a c r o s s two p l a t i n u m l e a d s which suspended the e n t i r e assembly from the top end f i t t i n g o f the v e r t i c a l f u r n a c e tube. Oxygen f u g a c i t y ( f 0 ) was c o n t r o l l e d by a d j u s t i n g the m i x i n g r a t i o o f a CO/CO2 gas m i x t u r e f l o w i n g through the f u r n a c e tube; i t was m a i n t a i n e d a t the q u a r t z - f a y a l i t e - m a g n e t i t e (QFM) b u f f e r (2, 3) and was m o n i t o r e d by r e c o r d i n g the EMF from a s o l i d s t a t e 0 s e n s o r i n the form o f a C a O - s t a b i l i z e d Z r 0 tube which extended from the lower end o f the f u r n a c e tube i n t o the h o t zone next t o the sample ( 4 ) . Pure 0 a t 110 kPa (1 atm) was c i r c u l a t e d i n s i d e the Z r 0 tube as the r e f e r e n c e gas. The CO was Matheson C. P. grade o r e q u i v a l e n t ; the C 0 was Matheson Coleman Instrument grade o r e q u i v a l e n t . Sample temperatures were measured by a Pt/10Rh thermocouple i n the hot zone; the thermocouple had been c a l i b r a t e d a t the g o l d p o i n t (1063°C). Run times v a r i e d from 77 hours a t 1270°C t o 738 hours a t 1130°C. The sample was quenched i n d e i o n i z e d water by e l e c t r i c a l l y f u s i n g the b r i d g e w i r e , which dropped the sample out o f the f u r n a c e tube. The quenched sample was mounted and p o l i s h e d f o r a n a l y s i s . The e l e m e n t a l c o m p o s i t i o n and the phases p r e s e n t were d e t e r m i n e d by wavelength d i s p e r s i v e X-ray a n a l y s i s w i t h a f u l l y automated JEOL 733 Superprobe. The weight p e r c e n t a g e s o f the phases p r e s e n t were d e t e r m i n e d from c o n s t r a i n e d l e a s t squares a n a l y s i s o f the b u l k c o m p o s i t i o n and the c o m p o s i t i o n s of the i n d i v i d u a l phases i n each experiment. Weight p e r c e n t a g e s were c o n v e r t e d t o volume p e r c e n t a g e s u s i n g e s t i m a t e d d e n s i t i e s f o r the m e l t and c r y s t a l l i n e phases. The c a l c u l a t e d volume p e r c e n t a g e s were compared w i t h t h o s e d e t e r m i n e d by r e f l e c t e d l i g h t p o i n t counts (1000 p t s ) o f s e l e c t e d e x p e r i m e n t s . The r e s u l t s o f the two methods a r e i n good agreement ( F i g u r e 1 ) . The s i z e d i s t r i b u t i o n was not d e t e r m i n e d . 2

2

2

2

2

2


17.

WEED ET AL.

Rheological

Properties

of Molten

Kilauea

Iki Basalt

225

Viscometry. The s t a r t i n g m a t e r i a l f o r t h e v i s c o s i t y d e t e r m i n a t i o n s was t h e f u s e d and r e - g r o u n d g l a s s d e s c r i b e d above. The v i s c o m e t e r was o f t h e r o t a t i n g cup C o u e t t e type i n which t h e t o r q u e and temperature were measured a t t h e bob (J>). The cup was c y l i n d r i c a l i n shape w i t h a r a d i u s o f 10.0 mm and a h e m i s p h e r i c a l bottom. The l e n g t h o f t h e c y l i n d r i c a l p o r t i o n was 32.5 mm. The bob was t h e same shape, w i t h a r a d i u s o f 8.25 mm and an o v e r a l l l e n g t h o f 88.1 mm. They were a l i g n e d w i t h t h e hemispheres c o n c e n t r i c by means o f x-y-z micrometer a d j u s t i n g screws on t h e framework w h i c h s u p p o r t e d t h e bob. They were f a b r i c a t e d from Pt/30Rh a l l o y , w i t h an F e - r i c h s u r f a c e produced by h e a t i n g w i t h a m e l t (25 weight p e r c e n t Fe3Û4, 75 weight p e r c e n t Na2SiÛ3) under f 0 c o r r e s p o n d i n g t o t h e i r o n - w u s t i t e b u f f e r (_3). T h i s i s i n t e n d e d t o m i n i m i z e Fe t r a n s p o r t from t h e K i l a u e a I k i m e l t t o t h e bob and cup (6). Oxygen f u g a c i t y was c o n t r o l l e d by p a s s i n g CO/CO2 gas m i x t u r e s t h r o u g h t h e i n n e r sample t u b e , which was i s o l a t e d from t h e r e s t o f t h e f u r n a c e by w a t e r - c o o l e d r o t a t a b l e mercury s e a l s a t t h e i n l e t and o u t l e t ends. Flow r a t e s were c o n t r o l l e d by v e r n i e r t h r o t t l e v a l v e s and b a l l - t y p e f l o w m e t e r s ; t h e meter s e t t i n g s were c a l c u l a t e d from t h e m a n u f a c t u r e r ' s p u b l i s h e d c u r v e s (_7) · The CO/CO2 r a t i o was a d j u s t e d t o g i v e an f02 c o r r e s p o n d i n g t o an e x t r a p o l a t i o n o f t h e q u a r t z - f a y a l i t e - m a g n e t i t e (QFM) b u f f e r (_2_3)· The t o t a l f l o w r a t e was 581 cm^/min c o r r e s p o n d i n g t o a l i n e a r v e l o c i t y o f 0.9 cm/sec a t room temperature and p r e s s u r e ; t h i s had been shown t o be l a r g e enough t o a v o i d unmixing o f t h e gases due t o t h e r m a l d i f f u s i o n e f f e c t s ( 8 ) . The CO was Matheson C. P. grade o r e q u i v a l e n t ; t h e CO2 was Matheson Coleman Instrument grade o r equivalent. Temperature was measured by a Pt6Rh/Pt30Rh thermocouple which had been c a l i b r a t e d a g a i n s t a pyrometer and s t a n d a r d lamp, w i t h a p p r o p r i a t e c o r r e c t i o n s f o r i n t e n s i t y l o s s e s due t o windows and a r e f l e c t i n g p r i s m i n t h e o p t i c a l t r a i n . The a c c u r a c y o f t h e temperature measurement was e s t i m a t e d t o be + 2°C (9). Torque was measured by a c a l i b r a t e d t o r s i o n b a r i n which t h e a n g u l a r d e f l e c t i o n and t o r q u e were r e a d from f o u r s t r a i n gauges mounted on t h e f a c e s o f t h e b a r and c o n n e c t e d as a Wheatstone bridge. The u n i t used i n t h e s e measurements had a range o f + 0.353 N.m (+ 50 o z . i n ) and d i g i t a l r e a d o u t t o 7.1 χ 10""^ N.m (0.1 oz.in). The tachometer was a t o o t h e d wheel and magnetic p i c k u p w i t h a range o f + 999 r e v / m i n , r e a d a b l e t o 1 r e v / m i n .


2

}

T h r e e t y p e s o f v i s c o m e t r y e x p e r i m e n t s were p e r f o r m e d : c a l i b r a t i o n measurements on a s t a n d a r d o i l t o d e t e r m i n e t h e e f f e c t i v e l e n g t h o f t h e c y l i n d r i c a l column o f l i q u i d , i s o t h e r m a l runs on t h e b a s a l t m e l t s , and p o l y t h e r m a l e x p l o r a t o r y runs on t h e b a s a l t m e l t s . C a l i b r a t i o n measurements were performed on B r o o k f i e l d o i l ( μ = 1 0 5 Pa.s) a t room temperature and under l a b o r a t o r y atmosphere. The e f f e c t i v e l e n g t h was d e t e r m i n e d o v e r a range which i n c l u d e d t h e l e n g t h o f t h e m e l t samples. Rotation speed was v a r i e d from 0 t o + 220 rev/min i n 40 rev/min s t e p s , w i t h i n c r e a s i n g speed v a l u e s a t even m u l t i p l e s o f 20 rev/min and d e c r e a s i n g speed v a l u e s a t odd m u l t i p l e s o f 20 r e v / m i n . The p o s i t i v e r o t a t i o n a l d i r e c t i o n was s e l e c t e d f i r s t . A t l e a s t two t o r q u e r e a d i n g s were taken a t each v a l u e o f t h e r o t a t i o n a l speed. The same p r o c e d u r e was f o l l o w e d d u r i n g i s o t h e r m a l runs on t h e b a s a l t m e l t s , e x c e p t t h a t t h e temperature was n o t e d f o r each t o r q u e ο



226

measurement a t c o n s t a n t r o t a t i o n a l speed i n o r d e r t o m o n i t o r t h e temperature i n c r e a s e due t o v i s c o u s energy d i s s i p a t i o n . The m e l t sample weight was about 6.65 g, which w i t h an assumed d e n s i t y o f 2.78 g/cnr* c o r r e s p o n d e d t o a g e o m e t r i c a l l e n g t h o f 14.7 mm f o r the c y l i n d r i c a l p a r t o f t h e sample. The temperature s e t t i n g s were approached from above by g o i n g from room temperature t o 1260°C o r 1270°C a t 100°C/hr t o 150°C/hr, then c o o l i n g t h e system a t about l°C/min u n t i l t h e d e s i r e d temperature was r e a c h e d . The e f f e c t o f c h a n g i n g t h e h e a t i n g and c o o l i n g r a t e s on t h e v i s c o s i t y was n o t explored. P o l y t h e r m a l runs were made a c o n s t a n t r o t a t i o n a l speed, u s u a l l y 90 t o 100 rev/min, and were used t o e x p l o r e t h e temperature range o v e r which s u i t a b l e t o r q u e r e a d i n g s c o u l d be o b t a i n e d .


R e s u l t s and D i s c u s s i o n C r y s t a l l i z a t i o n Sequence. T a b l e I shows the major element b u l k c o m p o s i t i o n o f t h e s t a r t i n g m a t e r i a l s used i n o u r e x p e r i m e n t s and t h o s e o f Shaw e t a l . ( 1 0 ) . K i l a u e a I k i b a s a l t c o n t a i n s l e s s AI2O3 and CaO than t h e i r m a t e r i a l , and much more MgO. Both a r e w i t h i n t h e normal range f o r b a s a l t i c l a v a s . Table I.

O x i d e , Wt.%

2

3

2

3

-

2

p o 2

K 0 Ti0 MnO

5

2

2

TOTAL *A11

Kilauea I k i 46.29 10.44 17.90 11.34*

S1O2

A1 0 MgO FeO Fe 0 CaO Na 0

Analyses of S t a r t i n g

8.49 1.84 0.22 0.40 1.89 0.19 99.90

Material

Shaw e t a l . U 0 ) 50.14 13.37 8.20 10.13 1.21 10.80 2.32 0.27 0.53 2.63 0.17 99.77

i r o n as FeO

The e x p e r i m e n t a l r e s u l t s o b t a i n e d a t t h e QFM b u f f e r a r e l i s t e d i n T a b l e I I . and t y p e f o r m u l a s f o r t h e v a r i o u s m i n e r a l s e r i e s i n T a b l e III. O l i v i n e and chrome s p i n e l a r e t h e o n l y c r y s t a l l i n e phases which o c c u r between 1240°C and 1179°C; c l i n o p y r o x e n e and p l a g i o c l a s e f e l d s p a r c r y s t a l l i z e a t a p p r o x i m a t e l y 1170°C. The c o n c e n t r a t i o n o f c r y s t a l s i n c r e a s e s from about 22 weight p e r c e n t t o about 28 weight p e r c e n t between 1250°C and 1180°C. The l i q u i d l i n e o f d e s c e n t i s c h a r a c t e r i z e d by a s l i g h t S1O2, AI2O3 and a l k a l i enrichment and an FeO and MgO d e p l e t i o n . The volume p e r c e n t a g e o f m e l t as a f u n c t i o n o f temperature i s shown i n F i g u r e 1. The b r e a k i n s l o p e a t a p p r o x i m a t e l y 1170°C c o r r e s p o n d s t o t h e appearance o f c l i n o p y r o x e n e and p l a g i o c l a s e f e l d s p a r (see Table I I . ) . The volume p e r c e n t a g e o f m e l t , V , i s g i v e n by E q u a t i o n s 1 and 2: m


17.

WEED ET AL.

Rheological

Properties

of Molten

Kilauea

Table I I . Results o f Selected K i l a u e a I k i Liquidus


1

Exp 1 No.

Time (Hrs)

Temp

14

93.0

1240

9

189.5

1230

8

24.0

1219

10

290.0

1209

12

289.0

1189

13

364.0

1179

16

380.0

1170

19

400.0

1160

20

400.0

1149

a) b) c)

Experiments

Wt % Melt

Vol % Melt

Experiment Products

CO

227

Iki Basalt

3

o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, glass o l i v i n e , chrome spinel, clino pyroxene, p l a g i o clase, glass ο1iν i n e , chrome spinel, clino pyroxene, p l a g i o clase, glass o l i v i n e , chrome spinel, clino pyroxene, p l a g i o clase, glass

78.1

71.8 80. 2

b

76.1

C

77.3

74.8

76.2

74.2

63.8

72.5

71.8

71.5

69.6

68.5

54.7

53.5

40.7

49.8

Volume p e r c e n t o f m e l t was d e t e r m i n e d by a 1000 p o i n t mode on metallograph. Weight p e r c e n t o f m e l t was d e t e r m i n e d by c o n s t r a i n e d l e a s t squares a n a l y s i s o f phase c o m p o s i t i o n s . Volume p e r c e n t g l a s s was d e t e r m i n e d by an 850 p o i n t mode on metallograph.

Table I I I .

Type Formulae

Name Olivine Chrome S p i n e l

Series

Type Formula (Mg, F e ) S 1 O 4 AB2O4

A = Mg, F e Β = Al, Fe Clinopyroxene

f o r Mineral

2 +

3 +

2 +

, Zn, M n , N i , Mn , Cr 3 +

ABS12O5 2 +

A = Mg, F e , Ca, Na Β = Mg, F e , A l Ranges from NaAlSi3U3 2 +

Plagioclase

to CaAl2Si 0g 2



228

V

m

(01+Chsp) = 0.157 V

= 1.36

m

T(°C)

T(°C)

- 114.0, where T(°C) > 1170,

- 1522.7, where T(°C)

(1)

< 1170.

(2)

E x t r a p o l a t i o n o f E q u a t i o n 1 t o V =100 c o r r e s p o n d s t o T=1360°C f o r the l i q u i d u s . E x t r a p o l a t i o n o f E q u a t i o n 3 t o V =0 y i e l d s T=1119°C f o r the d i s a p p e a r a n c e o f l i q u i d , the s o l i d u s t e m p e r a t u r e . T h i s i s a complex system f o r which complete phase diagrams a r e not a v a i l a b l e ; p s e u d o t e r n a r y diagrams such as those p r e s e n t e d by Grove e t a l . (_1) f o r s i m i l a r c o m p o s i t i o n s a r e g e n e r a l l y a p p l i c a b l e t o t h i s composition. m


m

Viscometry. D u r i n g v i s c o s i t y measurements s i g m o i d a l t o r q u e v e r s u s r o t a t i o n speed c u r v e s a r e o b t a i n e d a t a l l i n v e s t i g a t e d temperatures. The c u r v e s a r e l i n e a r a t r o t a t i o n speeds l e s s than 0.4 r e v s / s e c , w i t h a p o s i t i v e s l o p e . The c u r v e s become concave toward the r o t a t i o n speed a x i s a t h i g h e r r o t a t i o n r a t e s , i n d i c a t i n g p s e u d o p l a s t i c b e h a v i o r ( 1 1 ) . T h i s b e h a v i o r becomes more pronounced a t low temperature as the c o n c e n t r a t i o n o f suspended c r y s t a l s increases. A l s o , a t a g i v e n r o t a t i o n a l speed, the o b s e r v e d t o r q u e appears t o be s l i g h t l y lower f o r n e g a t i v e r o t a t i o n than f o r positive rotation. This indicates s l i g h t thixotropic behavior of t h e sample, s i n c e p o s i t i v e r o t a t i o n i s used f i r s t d u r i n g experiments. At temperatures n e a r 1149°C, t o r q u e measurements a r e more e r r a t i c than a t h i g h e r t e m p e r a t u r e s . T h i s may be due t o s e g r e g a t i o n o f c r y s t a l s which causes the sample t o r o t a t e i n t e r m i t t a n t l y as a r i g i d body, o r due t o l o c a l i z e d r e m e l t i n g o f c r y s t a l s by v i s c o u s h e a t i n g which i n c r e a s e s a t lower t e m p e r a t u r e s . We have a n a l y z e d the r e s u l t s i n d i c a t e d by E q u a t i o n 3: log

Ιτ

I

= Α

+ A

χ

2

i n terms of the power

law

l o g Idu/dxl

(3)

where I T y I i s the a b s o l u t e v a l u e o f the shear s t r e s s and Idu/dxl the a b s o l u t e v a l u e o f the s h e a r r a t e , c a l c u l a t e d by a m o d i f i c a t i o n o f the method o f K r i e g e r and E l r o d (12) which a p p l i e s t o non-Newtonian systems. The a p p a r e n t v i s c o s i t y , μ , i s X

μ

= T /(du/dx) y x

(4)

The f l o w c u r v e , F i g . 2, i s a p l o t o f E q u a t i o n 3 showing e x p e r i m e n t a l r e s u l t s o b t a i n e d a t the 1186°C i s o t h e r m . Fig. 3 i s a log-log plot o f a p p a r e n t v i s c o s i t y as a f u n c t i o n o f s h e a r r a t e a t the same temperature. The apparent v i s c o s i t y d e c r e a s e s w i t h i n c r e a s i n g s h e a r r a t e , which i s c h a r a c t e r i s t i c f o r p s e u d o p l a s t i c systems (11). The l o g a r i t h m o f the v i s c o s i t y a t u n i t s h e a r r a t e , l o g μ , i s c a l c u l a t e d from E q u a t i o n 3: 0

log

μ

0

= Αχ

(5)

T a b l e IV g i v e s μ as a f u n c t i o n o f t e m p e r a t u r e . It v a r i e s from 9 Pa.s a t 1249°C t o 879 Pa.s a t 1149°C. The a c c u r a c y i s e s t i m a t e d as + 15% above 1170°C; a t 1149°C, where the system shows e r r a t i c b e h a v i o r , the a c c u r a c y i s e s t i m a t e d as + 50%. 0


Rheological


WEED ET AL.

Properties

of Molten

1200

Kilauea

Iki Basalt

1150

T,°C F i g u r e 1. Volume p e r c e n t and weight p e r c e n t m e l t as a f u n c t i o n o f temperature f o r K i l a u e a I k i b a s a l t . V e r t i c a l bars i n d i c a t e two s t a n d a r d d e v i a t i o n s .

2.5 Ii

1.0

ι

I

I

1.4 log

ι

ι

ι

'

»

1.8 (Shear Rate,

•

'

t

'

2.2 sec

F i g u r e 2. L e a s t squares f i t o f l o g (Shear S t r e s s ) v s . l o g (Shear R a t e ) f o r K i l a u e a I k i b a s a l t a t 1186°C. V e r t i c a l b a r i n d i c a t e s two s t a n d a r d d e v i a t i o n s .



230

T a b l e IV. Apparent A c t i v a t i o n E n e r g i e s from L e a s t Squares A n a l y s i s o f l o g μ v s . 1/(T,K) f o r K i l a u e a I k i B a s a l t , Halemaumau B a s a l t , and C o a l S l a g X 0

System

Kilauea I k i


Halemaumau Coal Slag X

T,°C

1249-1170 1170-1150 1300-1158 1158-1125 1482-1330 1330-1260

Apparent A c t i v a t i o n Energy K c a l mol""l

Standard D e v i a t i o n L e a s t Squares F i t

123 + 10 452 + 21 8 6 + 9 635 + 64 5 3 + 1 424 + 27

.09 .04 .12 .18 .013 .14

The r e s u l t s o f l e a s t - s q u a r e s a n a l y s e s o f l o g y v s . (1/T,K) a r e shown i n F i g u r e 4 and T a b l e V f o r t h i s i n v e s t i g a t i o n on K i l a u e a I k i b a s a l t , f o r t h e work o f Shaw on Halemaumau b a s a l t (1£,13) and f o r Corey's r e p o r t on C o a l S l a g X ( 1 4 ) . The K i l a u e a I k i d a t a show a sharp i n c r e a s e i n s l o p e a t 1170°C as i n d i c a t e d by the l i m i t i n g s t r a i g h t l i n e s above and below t h i s t e m p e r a t u r e . Below 1170°C, a p p r e c i a b l e c r y s t a l l i z a t i o n o c c u r s as shown i n T a b l e II and F i g . 1, and the system shows s t r o n g l y p s e u d o p l a s t i c behavior. Shaw's r e s u l t s on Halemaumau b a s a l t ( 1 3 ) , which i s a H a w a i i a n b a s a l t q u i t e s i m i l a r t o K i l a u e a I k i , show a sharp i n c r e a s e i n s l o p e a t 1158°C. T h i s system shows p s e u d o p l a s t i c b e h a v i o r a t 1125°C and Newtonian b e h a v i o r a t h i g h e r temperatures. The r e s u l t s o f Corey (14) on C o a l S l a g X i n d i c a t e a sharp change i n r h e o l o g i c a l b e h a v i o r a t 1330°C. H i s o r i g i n a l paper g i v e s no d e t a i l s on t h e c a l c u l a t i o n o f t h e v i s c o s i t y r e s u l t s , and no i n f o r m a t i o n on the c r y s t a l l i z a t i o n sequence o f the c o a l s l a g on which they were obtained. The s i m i l a r i t y o f t h e b a s a l t and c o a l s l a g d a t a i n d i c a t e s t h a t r h e o l o g i c a l b e h a v i o r o f the c o a l s l a g may be a f f e c t e d by suspended c r y s t a l l i n e m a t e r i a l a t temperatures n e a r 1330°C. A r e c e n t study on s l a g g i n g i n l a r g e c o a l - b u r n i n g f u r n a c e s c o r r e l a t e s the s l a g g i n g b e h a v i o r w i t h ash c o m p o s i t i o n , a s h p a r t i c l e morphology, and c a l c u l a t e d c r i t i c a l v i s c o s i t y temperature T ( 1 5 ) . The methods o f the p r e s e n t i n v e s t i g a t i o n c a n be a p p l i e d i n o r d e r t o measure the c r i t i c a l v i s c o s i t y temperatures and c o m p o s i t i o n s d i r e c t l y , which s h o u l d improve the e x p e r i m e n t a l b a s i s f o r the c o r r e l a t i o n . Q

c v



WEED ET AL.

Rheological

1 16 I 1.0

ι

Properties

ι

ι

ι 1.4

log

of Molten

1—ι

1

Kilauea

Iki Basalt

»—J

1

"

1.8 (Shear Rate,

1—

2.2 sec

)

F i g u r e 3. Log (Apparent V i s c o s i t y ) v s . l o g (Shear R a t e ) f o r K i l a u e a I k i b a s a l t a t 1186°C. V e r t i c a l b a r i n d i c a t e s two standard d e v i a t i o n s .

0 0 ' 5.6

1

'

1

1

1

1

1

1

— —

6.0

1

1

1

6.4

1

—

1

1

— — 6.8

1

— ' 7.2

H

10 /(T,K) F i g u r e 4. L e a s t squares a n a l y s i s o f l o g ( V i s c o s i t y ) v s . r e c i p r o c a l temperature. P r e s e n t s t u d y O ; Shaw ( 1 3 ) Δ ; Corey (14) • . V e r t i c a l b a r s i n d i c a t e two s t a n d a r d d e v i a t i o n s .


232


T a b l e V· Apparent V i s c o s i t y a t U n i t Shear Rate ( μ ) v s . Temperature (t,°C) f o r K i l a u e a I k i B a s a l t i c L a v a 0


Run No. 57 63 58 64 59 65 60 66 61 62 67 68

T,°C 1249 1249 1235 1229 1220 1208 1201 1188 1186 1171 1170 1149

μ, Pa.s 13 9 9 14 15 25 38 51 52 71 94 879

I n b o t h t h e s t u d i e s on b a s a l t s , t h e b r e a k s i n t h e s l o p e o f the l o g μ v s . (1/T,K) c u r v e s o c c u r a t 20 t o 30 volume p e r c e n t o f suspended c r y s t a l s . The non-Newtonian b e h a v i o r o f t h e s e m o l t e n s i l i c a t e s u s p e n s i o n s appears t o a r i s e from the i n c r e a s i n g c o n c e n t r a t i o n o f suspended c r y s t a l s i n t h e m e l t . T h i s s u g g e s t s t h a t i n m o d e l i n g f l u i d f l o w i n s i l i c a t e systems, power law b e h a v i o r s h o u l d be c o n s i d e r e d when t h e suspended c r y s t a l c o n c e n t r a t i o n exceeds 20 volume p e r c e n t . 0

Acknowledgments T h i s work was performed under t h e a u s p i c e s o f t h e U.S. Department o f Energy by t h e Lawrence L i v e r m o r e N a t i o n a l L a b o r a t o r y under c o n t r a c t number W-7405-ENG-48.

Literature Cited 1. 2.

3. 4.

5.

Grove, T. L.; Gerlach, D. C . ; Sando, T. W. Contrib. Mineral. Petrol. 1982, 80, 160-182. Deines, P; Nafziger, R. H . ; Ulmer, G. C . ; Woermann, E. "Temperature-Oxygen Fugacity Tables for Selected Gas Mixtures in the C-H-O System at One Atmosphere Total Pressure"; Bulletin, Earth and Mineral Sciences Experiment Station, No. 88, College of Earth and Mineral Sciences, The Pennsylvania State University, University Park, PA, 1971. Huebner, J . S. In "Research Techniques for High Pressure and High Temperature"; Ulmer, G. C . , Ed.; Springer-Verlag, New York, 1971; pp. 123-177. Williams, Richard J.; Mullins, O. "A System Using Solid Ceramic Oxygen Electrolyte Cells to Measure Oxygen Fugacities in Gas-Mixing Systems"; Technical Memorandum TMX-58167, Lyndon B. Johnson Space Center, Houston, TX 77058 1976. Weed, H. C . ; Dibley, L.; Piwinskii, A. J . "A High-Temperature Viscometer for Use at 100 kPa"; UCRL-52477, Lawrence Livermore National Laboratory, Livermore, CA 94550, 1978.


17. WEED ET AL.

Rheological Properties of Molten Kilauea Iki Basalt


6. 7.

233

Grove, T. L. Contrib. Mineral. Petrol. 1981, 78, 298-304. "The F and Ρ Tri-flat (Low Flow Rate) Variable Area Flowmeter Handbook; Application, Sizing, and Calibration Prediction Data", Catalog 10A9010, Fischer and Porter Co., Hatboro, Pa, Pub. 13317, September, 1959. 8. Darken, L. S.; Gurry, R. W. J. Am. Chem. Soc., 1945, 67, 1398-1412. 9. Weed, H. C.; Piwinskii, A. J.; Dibley, L. L. "Experimental Study of the Dynamic Viscosity of Some Silicate Melts to 1953K at 150 kPa", UCRL-52757, Lawrence Livermore National Laboratory, Livermore, CA, 94550, 1979, p. 2. 10. Shaw, H. R.; Wright, T. L . ; Peck, D. L . ; Okamura, R. Amer. Jour. Sci. 1968, 266, 225-64. 11. Skelland, A. H. P. "Non-Newtonian Flow and Heat Transfer"; J. Wiley and Sons, New York, 1967, pp. 5-12. 12. Krieger, I.; Elrod, H. J. Appl. Phys. 1953, 14, 134-6. 13. Shaw, H. R. Jour. Petrology 1969, 10, 510-535. 14. Corey, R. C. "Measurement and Significance of the Flow Properties of Coal-Ash Slag"; Bulletin No. 618, U. S. Bureau of Mines 1964, pp. 1-64. 15. Hazard, H. R. "Influence of Coal Mineral Matter on Slagging of Utility Boilers"; EPRI CS-1418, Project 736, Final Report, Electric Power Research Institute, Palo Alto, CA 94304, 1980. RECEIVED October 24, 1985


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