| 摘要 |
714,077. Wood preservatives. BOLIDENS GRUVAKTIEBOLAG. Aug. 27, 1951 [Aug. 26, 1950; Aug. 6, 1951], No. 20190/51. Drawings to, Specification. Class 140 In a soluble wood preservative of the kind containing compounds of pentavalent arsenic, hexavalent chromium and zinc and/or copper, the amounts of the compounds are such that the ratio of the sum of the number of gram atoms of chromium multiplied by three and the number of gram atoms of zinc and/or copper multiplied by two to the number of ,gram atoms of arsenic lies within the range of from 3 to 4 preferably between 3.4 and 3.6 and the ratio of the number of gram atoms of zinc and/or copper to the number of gram atoms of chromium lies within the range of 0.8 to 1.5. The preservatives may be manufactured from chromic acid, arsenic acid, metal oxides, hydroxides or carbonates or from metal chromates arsenates, and arsenic acid. In an Example a composition having percentage by weight composition ZnO 16.2, CrO3 24.8, As2O5 38.0, H2O 21.0 is obtained from 162 kg. of zinc oxide, 251 kg. chromic acid, 576 kg. arsenic acid (containing 66 per cent. AS2O5) and 14 kg. H2O. In another Example the preservative having percentage by weight composition of 15.8 CuO, 24.7 CrO3. 38.0 As2O5, 21.5 H2O is obtained from 126 kg. copper arsenate or carbonate, 576 kg. arsenic acid (containing 66 per cent. AS2O5), 250 kg. of chromic acid and 19 kg. of water.
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