Dealing with wollastonite lumps

Wollastonite is a major component of many of my glazes, but I hate the lumps that it forms, making sieving more difficult. Does anyone have any tips on dealing with wollastonite lumps? Things I've tried: 1)Extensive mixing with paint mixer on electric drill - not much help at all with reducing lumps 2)Stick Blender - can work okay on thinner glazes, but too much cavitation with thicker glazes for it to be effective. (Most of the glazes I am making are brushing consistency.)

Wollastonite agglomeration is a nuisance for me too. I find the older my supply is the worse it gets so I just buy a single 50lb bag at a time. Only thing I've found that cuts down on sieving time is whizzing it in a blender (with some of the glaze mixing water) does help. My main glazes have about 15% of it, takes a few batches to get it all whizzed up and scrape out the blender but saves sieving time in the long run. Even so I usually have a teaspoon or so left in the sieve (I use 80 mesh) so