Gold Determination Problem in Barium Production Waste

The most common method for gold content determination in raw materials is fire assay. An alternative to this method is atomic absorption in a solution obtained by dissolving an initial sample in aqua regia. This study focuses on the sludge of one of the chemical plants, in which the barite concentrate (barium in sulphate form) is fused with calcium chloride at coal presence, and then leached in water. Decomposition of samples in aqua regia followed by atomic absorption analysis, as well as fire assay, showed gold content in the sludge at the level of 1-4 gram per ton. The presence of infusible and chemically resistant compounds in the sludge does not allow to the reliable determination of the gold content. Sintering with sodium peroxide for decomposition of stable compounds at 700 ∘ C, dissolution of sinter in acidic solution, evaporation and fire assay of residue made it possible to establish a reliable concentration of gold in the sludge - 10-20 gram per ton. It was found that a direct determination of gold in acidic sinter leach solution provides inadequate values associated with the influence of the background. Keywords: Gold determination, barium sludge, fire assay, atomic absorptio

Technogenic Zinc Usage Possibilities Investigation for Gold Cementation

Industrial dusts with high zinc content are formed in nonferrous and ferrous metals metallurgy. Hydrometallurgical processing of such dusts can be used. In this case, alkaline solutions with high impurities content are formed. It is possible to produce zinc powder with different technological properties by electroextraction from mentioned alkaline solutions. This work describes investigation of zinc powders usage possibilities to gold cementation from cyanide solutions

Measurement of the W+W- Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Dilepton Events

We present a measurement of the W+W- production cross section using 184/pb of ppbar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W- -> l+l-vvbar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0+2.2-0.8 events. The resulting W+W- production cross section measurement of sigma(ppbar -> W+W-) = 14.6 +5.8 -5.1 (stat) +1.8 -3.0 (syst) +-0.9 (lum) pb agrees well with the Standard Model expectation.Comment: 8 pages, 2 figures, 2 tables. To be submitted to Physical Review Letter