Structural control of Na₂TiO₃ in pre‐treating natural rutile ore by alkali roasting for TiO₂ production

Abstract

To improve the use of natural rutile ore with fine particle size and high contents of MgO and CaO in China, a novel pre-treatment method of natural rutile ore by NaOH roasting to prepare a-Na 2 TiO 3 for TiO 2 production was proposed. g-Na 2 TiO 3 is a stable by-product that can lead to serious caking in the reactor and low titanium yield. Thus, structural control in alkali roasting is necessary. The influence of particle size of natural rutile ore, NaOH-toore mass ratio, roasting temperature and roasting time on the crystal forms of Na 2 TiO 3 was systematically investigated. The optimized reaction parameters were as follows: average particle size of natural rutile ore, À9.2 mm; NaOH-to-rutile mass ratio, 1.2; roasting temperature, 5508C; and roasting time, 70 min. In these conditions, the titanium conversion and the fraction of a-Na 2 TiO 3 exceeded 99.5% and 98%, respectively. Moreover, the addition of H 2 O or as-prepared partial a-Na 2 TiO 3 as crystal seeds into the reaction system could prepare the roasting product with a-Na 2 TiO 3 as its main phase using À45 mm (À325 mesh) natural rutile ore.

Polycaprolactone- Chitosan- Ag coatings on Ti6Al4V: Critical synergic aspects analyzed by Raman, EFM and contact angle

“…The peaks at 35, 40 and 54°correspond to the metallic titanium present in the Ti6Al4V substrate [2,14] and the peaks at 30, 33, 40, 53°are characteristic of the sodium titanate in Na2TiO3 form. Other researchers have reported these same peaks for Na 2 Ti 5 O 11 [12,13]. Sodium titanate has been considered an intermediate between polymeric coatings and metal substrates since in its hydrated state it has a gel configuration that allows the chemical-physical union of the polymer with the substrate.…”

“…The peaks at 27, 38, 48, 54 and 58°correspond to the crystalline phase of TiO 2 in the form of anatase. Other research after the alkaline treatment presented a crystalline phase of TiO 2 in form of rutile [12,13]. This phase was influenced by higher temperatures in the alkaline treatment and posterior heat treatments around 600°C for the Ti6Al4V samples [13].…”

Controlling the formation of Na2ZrSiO5 in alkali fusion process for zirconium oxychloride production

“…The study of the effect of different particle sizes of zircon on the ZrO 2 leaching rate was carried out at 750 °C with a 6:1 NaOH/zircon mole ratio, and 1 h roasting time. According to literature, a decrease in particle size will increase the ZrO 2 leaching rate, ascribed to the increased contact area between the reactants, and hence their reactivity [24]. Thus, to increase the rate of reaction, size A Table 2, along with the details of the zirconium-containing compounds.…”

Evaluación y caracterización de nanotubos de TiO2 sintetizados por vía hidrotérmica con aplicación en ingeniería de materiales

“…Sin embargo, en las muestras 1, 3 y 7 se presenta un pico agudo en 40º que sugiere la formación de titanatos de sodio que según lo reportado en el trabajo de Meng y colaboradores [23] A través del software de análisis XRD High Score Plus® se tomó el patrón de difracción de rayos X de la muestra 3 y al compararlo con posibles candidatos se obtuvo la cuantificación de las fases presentes como se muestra en la Figura 9, obteniendo un 50% de titanato de sodio, 35% de fase Anatasa y 15% de rutilo. Por lo anterior, se establece que la reacción logró pasar de una estructura altamente cristalina a una estructura con menos cristalinidad por el cambio de morfología; sin embargo, no se logró una pureza deseada por la presencia de titanato de sodio (Na 4 Ti 5 O 12 ).…”