Evaluation of Titanium Tetrachloride (TiCl4) as an Alternative Coagulant and Characterization of Recovered TiO2

Titanium tetrachloride (TiCl4) as an alternative coagulant to remove organic matters and nutrients from the effluent of the secondary wastewater treatment was evaluated by comparison of removal efficiency of total phosphorous to Al- and Fe-based coagulants. Also, the surface characteristics, elemental contents, and crystallinity of the TiO2 produced from wastewater sludge flocculated with TiCl4 coagulant were investigated depending on the calcination temperatures. The more dosages of coagulants were injected, the greater concentrations of the cations (Al+3, Fe+3, Ti+4) and hydrogen ions (H+) resulted in the lower pH. Also, TiCl4 formed larger and heavier flocs than other coagulants and resulted in greater T-P removal efficiencies with reduced amounts of dosage. The phase change of anatase and rutile crystalline structures of TiO2 incinerated from wastewater sludges of TiCl4 coagulant was observed at relatively high calcination temperatures due to the existence of mixtures of organic matters, nutrients, and various impurities in the wastewater sludges of TiCl4 coagulant. Both C and P atoms were found to be mainly doped in/on TiO2 and the C and P atom originated from residual carbon of the settled organic matters and phosphorus nutrients present in effluents from sewage treatment plant, respectively. Therefore, 600–800 °C is the optimal calcination temperatures for TiO2 produced from TiCl4 coagulant flocculated with effluents from sewage treatment plant.

New insights into pathways and kinetic of magnesiothermic reduction of titanium tetrachloride in titanium metallurgy

There is still no consensus on the reaction pathways and kinetic modeling of magnesiothermic reduction of titanium tetrachloride, and the theoretical innovations are required for further research of titanium metallurgy. We determined efficient reaction pathways via chemical reaction stoichiometry methodology, and proposed an innovative kinetic modeling approach of magnesiothermic reduction of titanium tetrachloride. We explained the reaction pathways by the steps of the phase change near the gas-liquid interfaces, the homogeneous reaction in the gas phase, the heterogeneous reduction near the gas-liquid interfaces, and the like dissolves like in the liquid phase. Net chemical reaction rate of titanium sponge decreased with decreasing of titanium tetrachloride feeding rata and with increasing of gauge pressure. The excellent fitness of the reaction rate constants, f(Δp) and k(Tin), show that the proposed kinetic equation accuately describes the reaction mechanism, and is reasonable and acceptable for magnesiothermic reduction of titanium tetrachloride in titanium metallurgy.

Properties of Bitumen Composition Modified by Petroleum Resins

It was advised to use aliphatic, cycloaliphatic, aromatic petroleum resins and their derivatives obtained by oxidation of resins with a mixture of hydrogen peroxide and acetic acid as bitumen polymer-modifiers. Petroleum resins were obtained by ionic polymerization of unsaturated compounds of liquid pyrolysis products under the influence of titanium tetrachloride-diethylaluminium chloride catalyst. It was established that the maximum values of adhesion of modified bitumen coatings to metal substrates, corresponding to the minimum values of the wetting angle of the metal surface coated with solutions of bitumen compositions with different content of the polymer modifier were achieved using oxidized resins. All modified bitumen coatings have low water absorptivity and high acid resistance, alkali resistance and salt resistance, which allow using them as protective coatings

Complex coagulants produced from bulk waste and industrial products

A series of experiments has been conducted and samples of complex coagulants have been obtained from the by-products of apatite-nepheline ore flotation (nepheline concentrate) and from refractory production waste — i. e. synthetic brucite. It was established that aqueous solutions of titanium tetrachloride can be used as an acid leaching reagent. The authors examined the process of recovering the principal active components with aqueous solutions of titanium tetrachloride and identified the priority mechanism behind leaching of metallic components with highly diluted aqueous solutions of titanium tetrachloride. The quantitative and qualitative composition of the obtained solutions of complex coagulants was analyzed. Modified magnesium coagulants were found to demonstrate high efficiency at high pH values of the treated water. At neutral pH values, complex aluminiumbearing reagents proved to be significantly more efficient than the conventional coagulants (i.e. aluminium sulphates and aluminium (oxy)chlorides). The obtained reagents were analyzed for their coagulation ability. Run-off and waste waters generated by an off gas purification unit in use at a non-ferrous metal casting site were used for the analysis. The analysis showed that, with the same dosage used, the modified aluminium coagulant is 30–35% more efficient than the conventional reagents. Experiments aimed at analyzing the water treatment efficiency in the case of water with high pH values (e.g. wastewater generated by a cement plant) showed that due to the use of inoculants in magnesium coagulants the water treatment efficiency can be increased by more than 20%. It was proved that the introduction of titanium compound hydrolysis products helps to significantly increase the water treatment efficiency irrespective of the principal component of the coagulant (aluminium or magnesium salt). This research was carried out as part of the funding programme aimed to support young research and teaching staff of D. Mendeleev University of Chemical Technology of Russia (Application: З-2020-013.).