Synthesis of Chromium-Doped Malayaite Pigments from Wastewater Containing Low Chromium(VI)

Abstract

A malayaite pigment was synthesized with wastewater containing low chromium (Cr)(VI) by a novel liquidphase reaction method. The effects of the particle size of the precursor and calcination temperature on the final product are examined. The result of scanning electron microscopy shows that the obtained precursor is amorphous and the particle size is approximately 250 nm. The results of X-ray diffraction and differential scanning calorimetry show that the complete transformation temperature was approximately 1050°C. Furthermore, the Commission International de l'Eclairage laboratory shows that the red color of as-prepared pigments is more saturated with a high a* value at 34.1. This process of malayaite pigment preparation via reuse of the Cr(VI)-containing wastewater is quite simple, economical, and energy-saving for the industry, and the products have a saturated red color. There is considerable foreground for the industrial application of this work.

Sol-gel Synthesis and Optical Properties of Malayaite Ceramic Colour Pigments

“…A broad, intense peak centered at around 500-550 nm (18180 cm -1 ) could be ascribed to the spin allowed 3 T 1 ↔ 3 T 2 transition of octahedral Cr 4+ (Lopez-Navarrete et al 2003). This similar peak was also reported by Lee and Lee (2008a) and Zhang et al (2010). A drop at around 650 nm is typical of the 3d 3 ions which are from the anti-crossing of the spin forbidden 1 E and 1 t 2 levels (Lopez-Navarrete et al 2003).…”

“…This result was likely associated with phase formation of malayaite which has been widely known to be occurring at very high temperatures. Zhang et al (2010) also reported an intense exothermic peak at 1065.6°C which was likely be related to crystallization or transformation process. From both TGA and DTA results, the gels were calcined at ≥ 1000°C.…”

“…Long calcination time has been stated to increase crystallinity (Harisanov et al 2003). Higher firing temperature might result in further sintering of stacked malayaite phase, decreasing the value of a (Zhang et al (2010). Faurel et al (2003) stated that the Cr-doped tinbased pink remained stable at 1280°C or above whereas Lee et al (2008a) also reported decomposition of malayaite phase into cassiterite at 1500°C.…”

Synthesis and characterization of cobalt doped green ceramic pigment from tannery sludge

“…The chrome resources can be recovered from remaining ashes and reused for industrial production [14,15]. In recent decades, the ceramic pigments prepared from the chromium-rich sludge are widely investigated [16,17]. Jesionowski et al [18] used post-galvanic waste solutions from a chromating process as raw material to prepare the green pigments.…”

Ceramic tiles with black pigment made from stainless steel plant dust: Physical properties and long-term leaching behavior of heavy metals

“…Recently, several researchers investigated the synthesis of inorganic black iron-chromite pigment with iron-or chromium-containing industrial wastes, and thereafter it was introduced into the ceramic matrix to produce black ceramic tiles (Tanisan and Turan, 2011;Hajjaji et al, 2011;Costa et al, 2008;Chen et al, 2015;Zhang et al, 2010;Zhang et al, 2014). Tanisan and Turan (2011) reported that the black porcelain tile can be prepared with less expensive pigments through sintering a mixture of 40% natural chromite and 60% iron-containing oxide waste from the steel rolling mill at 1200 ºC.…”