Top ceramic proppant 30/50 low density high pressure resistance, high conductivity, low acid solubility ... -20 mesh, 16-20 mesh, 16-30 mesh, 20-40 mesh, 30-50 mesh, 30-60 mesh, 40-60 mesh, 40-70 mesh, 70-140 mesh ... , Henan, ChinaNo.08 hydraulic frac sand for oil and gas 30/50 low density