Sorption of cesium and strontium radionuclides onto crystalline alkali metal titanosilicates

Hydrochloric Acidic Processing of Titanite Ore to Produce a Synthetic Analogue of Korobitsynite

“…Synthetic analogues of natural microporous titanosilicates, ETS-4 (zorite), IE-911 (sitinakite), SIV (ivanyukite), AM-4 (lintisite), etc., have many industrial applications, in particular, in waste cleaning [1,2], radionuclide conservation [3], (photo)catalysis [4,5], rare metal extraction [6,7], gas separation [8,9], and biociding [10]. Comparatively novel uses include the production of self-cleaning, sterilizing, and anti-fouling building materials (Figure 1), based on well photocatalytic activity of titanosilicates under visible light [11][12][13][14][15][16][17].…”

“…Therefore, the development of a new technology of titanite processing to obtain new titanosilicate photo-catalyzers is imperative. There are a few ways to obtain cheap titanosilicate materials: (1) to use rich titanite ore without its enrichment by flotation [19]; (2) to obtain other titanosilicates with similar photocatalytic activity but lesser temperature and time of crystallization; (3) to develop another technology that would allow a complete use of titanite. All these ways were put to use in the proposed technology of hydrochloric acidic processing of titanite to produce a synthetic analogue of korobitsynite, SKR, a rhombohedral Ti-dominant member of the labuntsovite group [20].…”

“…In this framework, there are four channel sets occupied by extra-framework Na cations and water molecules. A widest (FCD = 3Å) eight-membered channel (1), formed by four SiO 4 tetrahedra and four (Ti,Nb)O 6 octahedra, lies along c. Smaller six-membered channels (2) and 3, delimited by four tetrahedra and two octahedra, develop along b. A third six-membered channel (4), also formed by four tetrahedra and two octahedra, runs along a and intersects channel (2).…”

“…A widest (FCD = 3Å) eight-membered channel (1), formed by four SiO 4 tetrahedra and four (Ti,Nb)O 6 octahedra, lies along c. Smaller six-membered channels (2) and 3, delimited by four tetrahedra and two octahedra, develop along b. A third six-membered channel (4), also formed by four tetrahedra and two octahedra, runs along a and intersects channel (2). The largest channel (1) is intersected by channel (3), while channel (2) intersects channel (4).…”

Titanite Ores of the Khibiny Apatite-Nepheline-Deposits: Selective Mining, Processing and Application for Titanosilicate Synthesis

“…In this framework, there is a system of wide channels (≈6.1 Å), with extra-framework cations of K and Na and water molecules inside that can be easily exchanged with Rb + , Cs + , Tl + , Ag + , Sr 2+ , Ba 2+ , Cu 2+ , Ni 2+ , Co 2+ , La 3+ , Ce 3+ , Eu 3+ , Th 4+ , etc. [18][19][20]26]. Moreover, ( 137 Cs, 90 Sr, 154 Eu)-exchanged forms of ivanyukite can be transformed by heating into stable SYNROC-like titanate ceramics for long-time immobilization of these radionuclides [20].…”