摘要:
Formaldehyde is prepared by oxidative dehydrogenation of methanol in the presence of a silver catalyst, specific amounts of steam and specific amounts of an off-gas, of a specific composition, taken from the manufacture of formaldehyde. The reaction is started at a lower throughput of methanol and at a lower temperature. The formaldehyde obtainable by the process is a disinfectant, tanning agent and reducing agent, and a starting material for the manufacture of synthetic resins, adhesives and plastics.
摘要:
A method for producing decorations which are color-stable in a porcelain firing (glost firing), and a pigment composition suitable for this method, is disclosed. Inclusion pigments based on heavy-metal sulfides and selenides in an oxidic or silicate casing, especially ZrSiO.sub.4, result in more color-stable decorations in a porcelain firing if color-stabilizing auxiliary agents from the series of Zn compounds, especially ZnO or zinc-containing glass frits, or cerium(III) or cerium(IV) compounds, especially CeO.sub.2, are used in the decorative layer and/or glaze layer as color-stabilizing auxiliary agents. The amount used in the decorative layer is generally 5 to 50% by weight in the case of ZnO and CeO.sub.2, relative to the inclusion pigment. The pigment composition contains at least one of the color-stabilizing auxiliary agents in addition to an inclusion pigment.
摘要:
Platelike alkaline-earth ferrites and lead ferrites for memory cores are produced from impure initial substances by decomposing the initial substances with a molten, basic alkali compound, and the precursor separated off after dissolution in water is annealed for 0.5 to 6 hours at 600.degree. to 950.degree. C.
摘要:
Encapsulation pigments comprising chromophoric particles embedded in glaze-stable casings are prepared by means of calcination from the appropriate initial products. High yields and strong color intensities are obtained if the chromophoric substance or its initial compounds are bound in and/or to a zeolite and are calcined in this form with the remaining constituents.