30 mesh grade and wollastonite common grade together high density alubit grinding media is used silica and wollastonite are milled together for 12 hours or less to give a specified median particle size in particular examples the silica sand and calcium silicate wollastonite may be ground or milled to achieve a median particle size of up to 10 microns in this example of the invention a silica wollastonite slurry is formed by mixing 3500 kg of silica sand with 1500 kg of wollastonite and water to form a slurry like consistency the wollastonite may be selected from commercially available common grades of wollastonite including acicular wollastonite some examples of wollastonite are kemolite a60 and fw 70 c the starting particle size of the common grade wollastonite raw material is 99 passing 120 mesh screen the silica is available as silica sand which is commercially available as silica sand grade 30 to 40 mesh suitable addition of water is added to the silica wollastonite mixture in order to arrive at the desired slip density for the desired mixing blunger in one example of the invention 26 dry wt of the silica wollastonite mixture slurry is added to the mixing blunger thereafter a further step of the method is adding 14 wt of dry morwell clay carbonaceous ball clay grade to the silica wollastonite slurry mixture thereafter a further step is adding 0 1 of soda ash solution light soda ash grade na 2 co 3 by way of incremental amounts using a special dosing pump thereafter a further step is adding 17 19 wt of axedale clay high plastic white fired ball clay thereafter a further step is adding approximately half of a mixture of 0 2 wt.