The studies pertained to production of highly dispersed green pigments, precipitated in the form of chromium(III) and nickel(II) silicates. The experiments were conducted at four various temperatures (20, 40, 60 or 80°C), using distinct emulsion systems and precipitating agents, so that appropriately selected parameters of the process would permit to obtain pigments of optimum utilitary properties. The obtained silicates were subjected to studies on principal physicochemical properties, such as capacity to absorb water, dibutyl phthalate, paraffin oil and bulk density. The pigments were characterised also using modem investigative techniques: SEM to study morphology and DLS (dynamic light scattering) technique to examine particle size and tendency to form agglomerates.
PL
Przeprowadzone badania dotyczyły otrzymywania wysoko zdyspergowanych zielonych pigmentów strącanych w postaci krzemianów chromu(III) oraz niklu(II). Próby prowadzone były w czterech różnych temperaturach (20, 40, 60 i 80°C), przy użyciu odmiennych układów emulsyjnych i czynników strącających, tak aby odpowiednio dobrane parametry prowadzenia procesu pozwoliły pozyskać pigmenty o optymalnych właściwościach użytkowych. Otrzymane krzemiany i tlenki poddano badaniom podstawowych właściwości fizykochemicznych, takich jak chłonność: wody, ftalanu dibutylu oraz oleju parafinowego, a także gęstość nasypowa. Pigmenty te analizowano także poprzez wykorzystanie nowoczesnych metod badawczych - techniki SEM do badania morfologii oraz techniki DLS (dynamicznego rozpraszania światła) do badania struktury wielkości cząstek i ich tendencji do tworzenia aglomeratów.
Studies were conducted on the production of chromium(III) silicates, the green pro-ecological pigments. The pigments were precipitated from sodium silicate and chromium(III) sulphate solutions in the system of two emulsions prepared in hexane in the presence of a non-ionic surfactant as an emulsifier. The chromium(III) sulphate represented a reduction product of chromate(VI) compounds present in post-galvanic wastes. The reduction agent involved metanal in an acidic medium. The obtained products were subjected to a comprehensive physicochemical analysis, their dispersive and morphological properties were determined. The precipitated green products exhibiting intense colour, were uniform and their particles manifested a low tendency to form agglomerate structures.
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New method was worked out for utilisation of postgalvanic refuse containing chromates(VI) Chromates contained in the refuse solution were reduced to chromium(III) compounds using hydrogen peroxide or hydrazine. The obtained chromium(III) hydroxide was subsequently passed to a solution using sulphuric acid. The studies pertained production of pigments, chromium(III) silicates obtained by precipitation from solutions of chromium metasilicate and chromium sulphate. The obtained pigments were analysed using, modern investigative techniques: SEM technique in studies on morphology and DLS technique in studies on particle size and particle tendency to form agglomerate structure.
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Studies were performed on the production of highly dispersed green pigments, chromium(III) and nickel(II) silicates and oxides in emulsion systems. Appropriately selected parameters in which the process was conducted permitted to obtain pigments of optimum utility properties. The obtained pigments were subjected to a physicochemical analysis, i.a., their principal physicochemical properties were established, the including particle size, particle size distribution and the morphology of the particle surface.
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