rotary seal for polishing slurry

i'm looking for a rotary seal, either a face seal or radial seal, that is capable of sealing abrasive slurry (water and 5 micron aluminium oxide particles) at 20 bar pressure, 200 rpm, 6mm bore, 20mm approx outer diameter. we've tried ptfe lip seals but these wear very quickly. Deublin do some silicon carbide face seals which would do the job, but these are much too large to fit into our design. does anybody know of any other suppliers? thanks.