**2.2.2 X-Ray diffraction**

304 Advances in Crystallization Processes

influence nitric acid, in order to verify the form of crystallization of ZrTiO4 under these

The hydrolysis reaction to obtain zirconium titanate (ZT), ZrTiO4, was performed with the alkoxides zirconium n-propoxide (NPZ) (Dupont), and titanium isoproxide (TPT) Dupont, deionized water in the presence of nitric acid (Merck). The solvent used was *n*-propanol

The preparation of zirconium titanate powder from hydrolysis for alkoxides precursors, which was carried out separately, is illustrated in the block diagram reported in Figure 1.

> 1.37 mmol Zr(OC3H7)4 + 0.35 mmol deionized water in n-propanol Magnetic stirring constantly for 7 h, T = 20 °C

 **(sol II)**

Fig. 1. Process of preparation of zirconium titanate powder from hydrolysis for alkoxides

Thermogravimetric analyses (TGA) and thermodifferential analyses (DTA) of the powders were performed with an Harrop thermal analyzer, model STA 736, at a heating rate of

The synthesis performed with the mixture of alkoxides is described in Santos *et al*.

 **sol I + sol II** 

Magnetic stirring constantly for 2 days, T = 20 °C (The system became turbid when mixed)

The gel was dried in a chamber with an infrared lamp for 72 h

Thermal treatment at 500, 600 and 700°C for 8 h

conditions. The results were compared to the previous work (Santos *et al*, 2010).

**2. Materials and methods** 

**2.1 Preparation of the zirconium titanate powders** 

8.21 mmol Ti[OCH(CH3)2]4 + 5.5 mmol deionized water in n-propanol ; pH= 3 (HNO3) Magnetic stirring constantly for 7 h, T = 20 °C

 **(sol I)**

(Merck).

precursors.

**2.2 Characterization methods** 

10 K⋅ min-1 in air, with a 10 L⋅min-1 flow.

**2.2.1 Thermal analyses** 

In order to determine the mineralogical phases by X-Ray Diffraction (XRD), a Philips X-Ray Diffractometer was used (model X'Pert MPD) equipped with a graphite monochromator and rotational anode, operated at 40 kV and 40 mV. The data were collected via Cu-K<sup>α</sup> radiation at a step of 0.01° and time per step of 2 s, in order to determine the phases present in the samples.
