Abstract—The subject of the invention is a new reaction mechanism, during which natural ferrous titanium minerals can be dissolved using dilute sulfuric acid (40%) at 50°C in the presence of hydrogen in statu nascendi. In the new process, titanium raw materials are milled with a metal additive that is less noble than hydrogen in order to generate briquettes of the highest bulk density. The atomic hydrogen that develops at the contact surfaces when adding diluted sulfuric acid, leads to a partial reduction of quadrivalent to trivalent titanium, thereby initiating a spontaneous and almost complete dissolution at 50°C and ambient pressure. After the separation of the iron by means of crystallization, it is possible to extract a TiO 2 concentrate as raw material for the production of titanium alloys. Index Terms—Dissolution, Metal additive, Milling, Titanium raw materials. I. INTRODUCTION There are a large number of commercial and proposed processes for extracting TiO 2 concentrates from ferrous titanium minerals as a raw material for the production of pigments. These processes consist of a combination of thermal treatment, leaching, and physical separation stages [1]-[22]. The iron is converted into soluble Fe² + or elementary iron by means of reduction at high temperatures, followed by acid leaching for the production of synthetic TiO 2 concentrates. So far, there is no process technology for direct leaching of ferrous titanium minerals with mineral acids at normal pT conditions for the dissolution of titanium and iron with the objective of generating a TiO 2 concentrate by means of hydrolysis. If an ilmenite concentrate that has been produced by means of conventional processing methods, such as density sorting, magnetic separation, or electrostatic sorting, is subjected to a 60 min leaching with 40% H 2 SO 4 at 95°C, the titanium recovery is no more than 0.05% max. and the iron recovery 0.3%. This study introduces a new method that allows the dissolution of ferrous titanium minerals, especially ilmenite, with diluted mineral acid at temperatures below 100°C and to produce high percentage TiO 2 concentrates after the separation of the iron [23]. Eberhard Gock is with the Institute of Mineral and Waste Processing, Waste Disposal and Geomechanics, Clausthal University of Technology, 38678 GERMANY. Volker Vogt is with the Institute of Mineral and Waste Processing, Waste Disposal and Geomechanics, Clausthal University of Technology, 38678 Clausthal, GERMANY. Marcela Achimovičová is with the Institute of Mineral and Waste Processing, Waste Disposal and Geomechanics, Clausthal University of Technology, 38678 GERMANY, on leave from the Institute of Geotechnics, Slovak Academy of Science, Košice, 04001 SLOVAKIA. II. MATERIALS AND METHODS Ilmenite concentrate with a grain size of 100% < 0.6 mm was used as input material with following chemical analysis: 45.6% TiO 2 (30.02% Ti), 34.43% Fe, 0.76% Si, 0.42% Al, 0.016% Cr, <50 ppm Th, <50 ppm U, 7 ppm Zr and <5 ppm P. Apart from ilmenite (FeTiO 3 ), the X-ray diffraction analysis (XRD) also showed hematite (Fe 2 O 3 ) and quartz (SiO 2 ). An industrial eccentric vibratory mill, type ESM-656 0.5 ks (Siebtechnik GmbH, Germany), equipped with a satellite milling container was used for the milling. The kinematic analysis as well as the mechanical model of the eccentric vibratory mill can be found in numerous publications [24]-[27]. The following constant conditions were applied: satellite containers 5 l, degree of milling media filling 80%, grinding media shape and size 30 mm steel balls, amplitude 20 mm, frequency 960 min -1 . Mixing ratio ilmenite/aluminum powder = 19:1, activation time 15-180 min, 100-600 g/charge, argon atmosphere. For the leaching tests, a 1 l beaker was used as open agitator vessel with magnetic stirrer. Sulphuric acid was used as a leaching agent. The leaching temperature was controlled via a thermostated heating plate. Samples were taken at defined intervals. The sampled suspensions were filtered and analyzed by means of inductively coupled plasma spectrometry (ICP-OES). The solutions were collected for crystallization and hydrolysis. The following leach parameters were analyzed: 30-60% H 2 SO 4 , solids content 150-300 g.l -1 , leaching time: 5-60 min, start temperature 50 o C. A laser granulometer (Sympatec GmbH, Germany) was available for the particle size analysis. The agglomerates were detected by means of a scanning electron microscope (SEM). III. RESULTS AND DISCUSSION A. Reaction Mechanisms during Ultrafine Milling If a commercially available ilmenite concentrate is finely ground in a vibratory mill, which primarily applies impact stress, together with aluminum powder, there are two stages of stress: The stage of ultrafine milling and the stage of mechanical activation characterized by agglomeration [28]. A reproducible measure for the mechanical activation can be obtained by means of X-ray diffraction analysis. Lattice plane (104) was selected as the suitable lattice plane for ilmenite (see Fig.1). The ratio of the X-ray microstructure intensities of the raw material (I 0 ) to the X-ray microstructure intensities after a defined milling stress (I) yields a specific, characteristic value I/I 0 , which describes a specific active state of the milled material and the specific reaction-kinetic properties under defined conditions. Procedures for Treating Ferrous Titanium Raw Materials Eberhard Gock, Volker Vogt, and Marcela Achimovičová Int'l Journal of Research in Chemical, Metallurgical and Civil Engg. (IJRCMCE) Vol. 3, Issue 1 (2016) ISSN 2349-1442 EISSN 2349-1450 http://dx.doi.org/10.15242/IJRCMCE.IAE0316403 49