114 The N.Z. Journal op Science and Technology. [April 
of iron and slag. It was conceived that some such condition was arising, 
and that by frequent tappings the whole of the slag and titaniferous layer 
might be flushed through the tap-hole. This procedure was adopted in a 
trial and promised to prevent the forming of accretions in the hearth, but 
it entailed the loss of a quantity of iron with the slag, and is not, there¬ 
fore, a commerical process unless the ferro-titanium could be recovered 
from the slag and used to commercial advantage. 
Looking further into the question, it is estimated that 85 per cent, of the 
Ti0 2 in the ore is accounted for in the fluid slag, and that of the balance 
5 per cent, appears as a cinder high in Ti0 2 and 10 per cent, as ferro- 
titanium. From the analysis of the ore it is evident that the gangue forms 
a very infusible, slag, consisting of 50 per cent. Ti0 2 , 16 per cent. A1 2 0 3 , 
14 per cent. MgO, 11 per cent. Si0 2 , and 10 per cent. CaO. If any portion 
of this refractory mass escaped attack by the limestone flux in descent 
some part of it would doubtless sink through the slag bath and lie inert 
at the iron-level, and certainly any portion reaching the hearth when the 
latter is dry after tapping would lie there and gradually block up the 
furnace. The following analysis of a sample of cinder taken from the 
hearth corroborates this theory : 52T per cent. Ti0 2 , 15-6 per cent. A1 2 0 3 , 
13*3 per cent. CaO, 7-3 per cent. Mg.O, 9'5 per cent. Si0 2 , 1-1 per cent. S. 
This sample was viscous at 3,000° F., but when ground and intimately 
mixed with limestone became very fluid at this temperature. The possi¬ 
bility of the fused gangue escaping contact with the limestone flux could 
be greatly lessened, and probably entirely removed, by intimately mixing 
limestone with the ore to form a self-fluxing burden. The fine sand lends 
itself admirably to this procedure, as the limestone could be powdered, 
briquetted, and sintered with the ironsand and pulverized coal. This 
process has been patented, and a trial of it is about to be undertaken. 
The experience with these furnaces proves conclusively that fluid slags 
can be obtained containing as high as 20 per cent, of Ti0 2 , and this fact 
points to another procedure. If the ironsand containing 10 per cent, of 
Ti0 2 were mixed with equal parts of a non-tifaniferous ore a fluid slag 
containing 20 per cent, of Ti0 2 should be obtained, since the pig iron would 
absorb 1 per cent, of Ti0 2 ( i.e ., 0-6 per cent. Ti), leaving 4 per cent, of 
Ti0 2 in the mixed burden, which would on the same basis as before amount 
to 20 per cent, of the gangue. This method has been developed success¬ 
fully by Bachman at Port Henry for dealing with the titaniferous ores of 
New Jersey. The process, however, might be objectionable on account 
of a poorer pig being the outcome. The pig obtained from the ironsand 
alone is of exceptional quality, giving 25 per cent, greater breaking-strength 
and deflection than ordinary pig iron, and forming castings with an 
unsurpassed finish. Further, the steel produced from the pig has excep¬ 
tional strength, ductility, and malleability. The pig iron has a ready 
tendency to chill, even in ordinary sand casting with Si 2-5 per cent, and 
S 0-04 per cent., when the chill is only to a depth of in Personally, 
I believe this chilling tendency is due to the oxygen content rather than 
to the titanium carbide, and therein the modern theory advanced by the 
late J. E. Johnson, jun., supports me. One fact witnessed in evidence 
of this theory was the fact that pig produced by the first ferro-coke process 
did not chill readily, even though Si was only 0-9 per cent, and S 0-06 per 
cent.; and this pig was presumably very free from O, since the ore was 
very thoroughly deoxidized. As the ore is high in FeO, it is reasonable 
to expect that deoxidization under ordinary blast-furnace conditions is 
slow and that the pig produced from the ore by the later process is high 
in O, and this therefore is the cause of the chilling tendency. 
