Research of Polymetallic Sulfide Industrial Waste Nitric Acid Treatment

Thermodynamic and kinetic features studies of polymetallic sulfide industrial waste nitric acid leaching were carried out. Elemental and phase composition of investigated raw material were studied with X-ray diffraction and electron microscopy methods. Calculations of the Gibbs energy change for the likely reactions of sulfide minerals with nitric acid were performed. In order to determine the most probable conditions of the sulfide industrial waste leaching in nitric acid, as well as the mutual influence of the produced pulp components on the performance of the process, the kinetics evaluation of multicomponent sulfide industrial waste in a nitric medium was studied using mathematical methods. Keywords: nitric acid leaching, polymetallic sulfide industrial waste, Gibbs energy change, kinetic feature

Alkali Fusion-Leaching Method For Comprehensive Processing Of Fly Ash

Fly ash, composed of mullite, hematite, amorphous silica and quartz, is a promising source for the recovery of alumina and silica. Desilication with help of NaOH and alkali fusion-leaching method and utilization of alumina and silica in the fly ash for preparation of sodalite and silica white were explored in this research. The samples were characterized by using wet chemical analysis and X-ray diffraction. The optimal extraction of SiO2 from Reftinskaya power plant fly ash was 46.2% with leaching at 95 oC for 3 h. Sodalite was synthesized at 200 °C for 1 h followed water leaching at 95 °C for 1 h. Silica white with specific surface area 180-220 m2/g was prepared by carbonation of the Na2SiO3 solution at 40 oC for 90-120 min. The as-prepared silica has a purity of 98,8%. The proposed method is suitable for the comprehensive utilization of the fly ash. Keywords: fly ash, alkali fusion, desilication, sodalite, silica white, carbonization, comprehensive utilizatio

Autoclave Precipitation Of Iron From Zinc Sulfate Solutions

Zinc concentrates processing technology that includes high-temperature roasting – leaching of cinder – purification of leached liquor – electrowinning is the most widely used technology. Purified solution, which is fed to the electrowinning stage, has a high sensitivity to such an impurity as iron. The presence of iron in the zinc electrolyte has a negative influence both on the current efficiency and the quality of the cathode zinc. The application of autoclave equipment for iron removal from zinc sulfate solutions, obtained after the leaching stage of zinc cinder, is described in this article. All experiments were carried out with a model solution of following composition, g/L: 10-33 H2SO4, 1.5 Cu, 5 Mn, 110 Zn, 2.5 Fe. Neutralization and purification of the solution was implemented during low-temperature pressure leaching of the zinc cinder. The optimum conditions for iron precipitation from zinc solution are following: molar flow rate Zn(cinder) / H2SO4 = 1.3, t = 80 °C, τ = 1 hour, PO2 = 0.2 MPa. It was found, that the concentration of iron can be reduced up to 1-2 mg/L, whereas 83.5% of Zn and 52.1% of Cu being recovered into the solution from zinc cinder

BB flavour tagging using charm decays at the LHCb experiment

An algorithm is described for tagging the flavour content at production of neutral $B$ mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a $B$ meson with the charge of a reconstructed secondary charm hadron from the decay of the other $b$ hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes $B^+ \to J/\psi \, K^+$ and $B^0 \to J/\psi \, K^{*0}$ using $3.0\mathrm{\,fb}^{-1}$ of data collected by the LHCb experiment at $pp$ centre-of-mass energies of $7\mathrm{\,TeV}$ and $8\mathrm{\,TeV}$. Its tagging power on these samples of $B \to J/\psi \, X$ decays is $(0.30 \pm 0.01 \pm 0.01) \%$.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

Identification of beauty and charm quark jets at LHCb

Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select $b$- and $c$-quark jets is measured using data recorded by LHCb from proton-proton collisions at $\sqrt{s}=7$ TeV in 2011 and at $\sqrt{s}=8$ TeV in 2012. The efficiency for identifying a $b(c)$ jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum $p_{\rm T} > 20$ GeV and pseudorapidity $2.2 < \eta < 4.2$. The dependence of the performance on the $p_{\rm T}$ and $\eta$ of the jet is also measured

Search for B⁺c decays to the pp‾π⁺ final state

A search for the decays of the B + c meson to pp-π + is performed for the first time using a data sample corresponding to an integrated luminosity of 3.0 fb -1 collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. No signal is found and an upper limit, at 95% confidence level, is set, fcfu×B(B + c →ppπ + ) < 3.6×10-8 in the kinematic region m(pp) < 2.85 GeV/c2, p T (B) < 20 GeV/c and 2.0 < y(B) < 4.5, where B is the branching fraction and f c (f u ) is the fragmentation fraction of the b quark into a B c + (B + ) meson

Measurement of CP observables in B± → D(⁎)K± and B± → D(⁎)π± decays

Measurements of CP observables in B ± →D (⁎) K ± and B ± →D (⁎) π ± decays are presented, where D (⁎) indicates a neutral D or D ⁎ meson that is an admixture of D (⁎)0 and D¯ (⁎)0 states. Decays of the D ⁎ meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon, resulting in distinctive shapes in the B candidate invariant mass distribution. Decays of the D meson are fully reconstructed in the K ± π ∓ , K + K − and π + π − final states. The analysis uses a sample of charged B mesons produced in pp collisions collected by the LHCb experiment, corresponding to an integrated luminosity of 2.0, 1.0 and 2.0 fb −1 taken at centre-of-mass energies of s=7, 8 and 13 TeV, respectively. The study of B ± →D ⁎ K ± and B ± →D ⁎ π ± decays using a partial reconstruction method is the first of its kind, while the measurement of B ± →DK ± and B ± →Dπ ± decays is an update of previous LHCb measurements. The B ± →DK ± results are the most precise to date

Observation of the decay B0s → ψ(2S)K +π−

The decay B0 s → ψ(2S)K +π− is observed using a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. The branching fraction relative to the B0 → ψ(2S)K +π− decay mode is measured to be B(B0 s → ψ(2S)K +π−) B(B0 → ψ(2S)K +π−) = 5.38 ± 0.36 (stat) ± 0.22 (syst) ± 0.31 (f s/ fd)%, where f s/ fd indicates the uncertainty due to the ratio of probabilities for a b quark to hadronise into a B0 s or B0 meson. Using an amplitude analysis, the fraction of decays proceeding via an intermediate K∗(892)0 meson is measured to be 0.645 ± 0.049 (stat) ± 0.049 (syst) and its longitudinal polarisation fraction is 0.524 ± 0.056 (stat) ± 0.029 (syst). The relative branching fraction for this component is determined to be B(B0 s → ψ(2S)K∗(892)0) B(B0 → ψ(2S)K∗(892)0) = 5.58 ± 0.57 (stat) ± 0.40 (syst) ± 0.32 (f s/ fd)%. In addition, the mass splitting between the B0 s and B0 mesons is measured as M(B0 s ) − M(B0) = 87.45 ± 0.44 (stat) ± 0.09 (syst) MeV/c2

Observation of the B0 → ρ0ρ0 decay from an amplitude analysis of B0 → (π+π−)(π+π−) decays

Proton–proton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb−1, are analysed to search for the charmless B0 → ρ0ρ0 decay. More than 600 B0 → (π+π−)(π+π−) signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0 → ρ0ρ0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0 → ρ0ρ0 decays yielding a longitudinally polarised final state is measured to be fL = 0.745+0.048 −0.058(stat) ± 0.034(syst). The B0 → ρ0ρ0 branching fraction, using the B0 → φK∗(892)0 decay as reference, is also reported as B(B0 → ρ0ρ0) = (0.94 ± 0.17(stat) ± 0.09(syst) ± 0.06(BF)) × 10−6

Measurement of the CP-violating phase β in B0 → J/ψπ+π− decays and limits on penguin effects

Time-dependent CP violation is measured in the (—) B 0 → J/ψπ+π− channel for each π+π− resonant final state using data collected with an integrated luminosity of 3.0 fb−1 in pp collisions using the LHCb detector. The final state with the largest rate, J/ψρ0(770), is used to measure the CP-violating angle 2βeff to be (41.7 ± 9.6+2.8 −6.3)◦. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, (—) B 0 s → J/ψφ decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase φs is limited to be within the interval [−1.05◦,+1.18◦] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed