STONE CASTING Russian patent published in 1996 - IPC

FIELD: stone casting production. SUBSTANCE: stone casting has, wt.-%: SiO₂ 40.86-48.61; CaO 34.76-40.42; Al₂O₃; 2.05-3.06; MgO 6.18-10.84; P₂O₅ 1.20-1.68; Fe₂O₃ 0.47-0.71; Cr₂O₃ 0.99-2.26; SO₃ 0.39-0.97, and F′ 0.76-1.91. Properties: compression strength is 430-480 MPa, bending strength is 50-60 MPa, dielectric permeability: the parental is 5.1-5.5, after moistening for 7 days is 5.1-5.9, after 5 cycles of freezing at -50 C and thawing at 50 C is 5.2-6.1; after 6 thermic impacts at 800 C is 5.7-6.1, after 6 thermic impacts at 7 days of wetting is 6.0-6.5; dielectric loss (tgδ×10³): the parental is 1.5-4.9; after 7 days of wetting is 3.6-5.4; after 5 cycles of freezing at -50 C and thawing at 50 C is 4.7-8.1; after 6 thermic impacts at 800 C is 2.4-5.2; after 6 thermic impacts and 7 days of wetting is 4.8-8.4. EFFECT: improved dielectric properties, increased stability under climate and heat actions. 4 tbl