Study on strength characteristics and thickening characteristics of classified-fine cemented backfill in gold mine.

For some new mines, the utilization rate of tailings is not satisfactory when using unclassified tailings as backfill aggregate for cemented backfill. At the same time, with the progress of mineral processing technology, the tailings discharged by the concentrator gradually become finer. Therefore, cemented filling with fine-grained tailings as aggregate will become the development direction of filling technology in the future.

Synthesis, crystal structure and fluorescence of an unusual terbium carboxylate.

A novel terbium-containing fluorescent material, [Tb(CH3COO)2(H2O)3]Cl (1), has been prepared by a facile approach, i.e. an ultrasonic synthesis.

(μ-4,4'-Bipyridine-κN:N')bis-[triaqua-(4,4'-bipyridine-κN)(3-nitro-phthalato-κO)cobalt(II)].

The title binuclear complex, [Co(2)(C(8)H(3)NO(6))(2)(C(10)H(8)N(2))(3)(H(2)O)(6)], has been synthesized hydro-thermally from 3-nitro-phthalic acid (H(2)NPA), Co(NO(3))(2)·6H(2)O and 4,4'-bipyridine (4,4'-bipy). The mol-ecule of the complex occupies a special position on an inversion centre. The Co(II) atom has a slightly distorted octa-hedral environment formed by two N atoms from two 4,4'-bipy ligands, one carboxyl-ate O atom from NPA, and three O atoms of water mol-ecules.

Na(6)(H(2)O)(20)(V(10)O(28)) x 4H(2)O, a novel polyvanadate(V) with a three-dimensional framework.

The novel title polyvanadate(V), poly[[octa-mu-aqua-dodecaaqua-mu(4)-octacosaoxidodecavanadato-hexasodium] tetrahydrate], [Na(6)(H(2)O)(20)(V(10)O(28)).4H(2)O](n), contains [V(10)O(28)](6-) anions which lie about inversion centres and have approximate 2/m symmetry and which are linked to [Na(3)(H(2)O)(10)](3+) cations through two terminal and two mu(2)-bridging O atoms. The structure contains three inequivalent Na(+) cations, two of which form [Na(2)(H(2)O)(8)](n) chains, which are linked via NaO(6) octahedra involving the third Na(+) ion, thus forming a three-dimensional framework.