Study on the one-step acid conversion of the alkali conversion product of high titanium slag to prepare TiO2 of high purity

High titanium slag and KOH solution were used to synthesize potassium titanate whiskers. The acid conversion of potassium titanate whiskers in hydrochloric acid solution can directly prepare titanium dioxide. When the conversion temperature was 130 °C, the influence of hydrochloric acid concentration on the acid conversion of potassium titanate whiskers to titanium dioxide was investigated. The increase in hydrochloric acid concentration was beneficial to the removal of impurity elements. When the hydrochloric acid concentration was 15 wt%, the titanium dioxide content of the obtained product reached 99.1%. At an acid concentration below 15 wt%, the morphology of the acid conversion product was mainly multibranched and flower-like with a hierarchical structure. When the concentration was 20 wt% and 25 wt%, the morphology was slender fusiform. The phase of the obtained products was rutile. A detailed study was conducted at the hydrochloric acid concentration of 15 wt%, to investigate the phase and morphology transformation of potassium titanate whiskers into titanium dioxide. Only the splitting and dissolution of potassium titanate whiskers occurred in the initial stage. Rutile began to form at approximately 30 min. After that, the dissolution of potassium titanate and the formation of rutile continued. When the rutile crystals grew larger, they became multibranched hierarchical structures.