By mechanical activation of the concentrate, a finely dispersed mineral pigment has been produced. The TMC chemical treatment enables to increase titanium yield to final product (concentrate) almost by five times. The titanite-containing mineral compositions (TMC), which are disposed as apatite-nepheline ores processing tails, can be chemically treated with recovery of titanite concentrate for the synthesis of titanium functional materials. In this case, the intensity of Si response is over 9000, Ca-7000, and Ti-6000 ( Figure 6a), while these indicators for the original sample are 110, 170, and 100 correspondingly ( Figure 6b). Figure 6 shows data of the energy-dispersive analysis of concentrate particles ground in the planetary mill. Mechanical activation of the powder can be visually observed and confirmed by a whiteness indicator of original (60%) and ground (87%) material pre-set with the X-RtteSP-62 spectrophotometer. In the case under consideration, a high-energy impact is accompanied by disturbance of structural order in titanite grains and crystals, which leads to formation of a shock-resistant chemically active surface layer of microparticles. The activation stage represents a certain interest illustrated by an opportunity for preparation of titanium dioxide alloy powders of various purpose: for photocatalysis, anti-bacteriological materials, composites. The pigment preparation method is based on a concentrate ultra grinding process, which is accompanied not only by changes in particle size distribution, but also by transformation of particle surface due to mechanical activation. Calcium concentrates in the liquid phase, where it is recovered by crystallization in the form of calcium chloride -CaCl 2∙nHCl∙mH 2O (n: 0.1–0.15 m: 1–1.5). The X-ray fluorescence analysis shows that the solid phase consists of amorphous silica and titanium dioxide with anatase-rutile structure-DTK ( Figure 5). Under the conditions described above, calcium, titanium, and silicon leach into a liquid phase and depending on their solubility in a multi-component system TiO 2-SiO 2-CaO-HCl, solid and liquid phases develop. Further holding for the next 4 h involved stripping of SGM and its condensation with hydrochloric acid production. Then the suspension was heated until boiling, and mixed for 5 h while returning the produced steam-gas mixture (SGM) to the reaction area. A concentrate charge was gradually added to the acid heated up to 80 ☌ until titanite mass to acid volume ratio reached S:V liq = 1:3. Īcid decomposition of titanite concentrate was also conducted with 32% hydrochloric acid. The use of the composition in mixture of concrete increases its strength characteristics, which is confirmed by the authors of the publication. According to powder X-ray diffraction analysis, the obtained composition consists of aluminum and calcium phosphates, as well as silica ( Figure 4). The multicomponent filtrate was disposed of to obtain an amorphous precipitate, which was calcined at 500 ☌. The recovered concentrate contains 80% of titanite, which corresponds to titanium content of 31.5% in terms of TiO 2. Moisture was removed from the precipitate by drying at 105 ☌. ![]() Then the precipitate was separated by filtering, and washed from acidic mother liquor with distilled water (Tananaev Institute of Chemistry, Apatity, Russia). The suspension was mixed in a magnetic stirrer at a temperature of 20 ☌ and 40 ☌ for 3 h. While mixing the acid, a TMC charge was added to achieve a mass ratio S:V liq = 1:3–4. After grinding, TMC was treated to remove acid-soluble minerals (apatite and nepheline) with hydrochloric acid (HCl-37.5%) diluted to 30 and 50 g/L ( Table 2). ![]() įor crystal grain decomposition, TMC was ground in a ball mill at grinding media to concentrate ratio of 5:1 during 1 h. The rest minerals are almost not recovered because of the absence of demand for them and therefore, they are disposed at tailings storage facilities. However, the modern ANO processing aims at deeper recovery of apatite and partially nepheline. Five main rock-forming minerals are specified in the ore: apatite, nepheline, sphene, aegirine, and titano-magnetite ( Table 1), in which the content varies within certain ranges depending on the ore-bearing rocks. ![]() The Khibiny deposits of complex apatite-nepheline ores (ANO) are the largest ones not only in Russia, but also in the whole world. In the Murmansk region, where the mining industry is developing rapidly, the amount of waste increases by millions of tons annually. At the same time, maintenance of environmental standards for the functioning of enterprises is placed in the second place. ![]() The utilization of the industrial wastes from the processing of multicomponent mineral ores is a more complicated and expensive task than storing them in the dumps.
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