Sodium sulfide

About: Sodium sulfide is a research topic. Over the lifetime, 2851 publications have been published within this topic receiving 27733 citations. The topic is also known as: disodium sulfide.

Direct oxidative conversion of sodium sulfide to sodium sulfite by absorbing the heat of reaction in a fluidized bed system using adiabatic cooling

Abstract: Process for simultaneously producing sulfite pulping chemical from a spent pulping medium by the exothermic oxidative conversion of sodium sulfide to sodium sulfite and for the control of the temperature in exothermic reaction and also for employing the exothermic reaction heat to make steam to be mixed with air for use in said oxidation process. Ground particles of a spent pulping smelt are treated in a fluidized bed reactor in intimate contact with moving air enriched with steam for about 10 seconds to 2 hours, wherein the weight ratio of steam to air ranges from about 0.2 to 1 to 1.2 to 1. The temperature in the reactor is adiabatically controlled and the heat of reaction generated in the reactor is absorbed by adiabatic cooling to form the steam used in the reactor.

Performance evaluation of a gypsum-based desulfurizer for sulfur recovery from the smelter off-gas: Experimental analysis and thermodynamic performance

Abstract: To find some new desulfurizers for the smelter off-gas containing high levels of SO2, both the sulfur recovery performance and the regeneration performance of the sulfides of alkali metals and alkaline-earth metals were compared in both simulation and experiment. Although sodium sulfide(Na2S) showed a good sulfur recovery performance, its regeneration performance was poor due to the production of polysulfides. Calcium sulfide(CaS) was a feasible option of the desulfurizer because both its sulfur recovery performance and regeneration performance were satisfactory. CaS was prepared after the reduction of the commercial CaSO4(Red-Ca), the flue gas desulphurization gypsum(Red-FGD), the phosphogypsum(Red-P) and the titanogypsum(Red-Ti), respectively. The results showed that the performances of Red-Ca and Red-FGD were quite similar and both of them were distinctly better than Red-P and Red-Ti. According to XRF analysis and XRD patterns, the impurities in Red-P and Red-Ti reduced the activity of CaS. Both the su...

Transference Number Calculations for Sodium Polysulfides

Abstract: Transference numbers of sodium cations and sulfur anions in sodium polysulfide melts are calculated from previously determined experimental data. Concentrated electrolyte theory assuming a binary electrolyte consisting of sodium anions, sulfide cations, in a neutral sulfur solvent is used to relate the transference numbers to fundamental solution transport properties. Slopes of open-circuit potential measurements vs. melt composition on sodium-sulfur cells with and without transference are used to determine the sulfur anion and sodium cation transference numbers. The transference number of sodium cations is calculated from previous experimental data for two temperatures, 573 and 633 K, and range from 0.88 to 0.93 for sodium sulfide mole fractions between 0.20 and 0.34. These values for transference numbers presented here are more accurate than previous interpretations of these data where unity sodium cation transference numbers were assumed. The results of this work are shown to be important in the design of sodium-sulfur cells.

Solidification process with enhancement of heavy metals insolubilization

Abstract: The process for immobilizing a hazardous waste containing heavy metals comprises the steps of pretreating the waste by adding a sulfide to the hazardous waste so as to generate the sulfides of the heavy metals from the hazardous waste, mixing a chemical reagent with the pretreated waste, and blending the mixture of the chemical reagent and the pretreated waste with a pozzolanic material. The chemical reagent contains a mixture of a retarder and an accelerator. This process further comprises the step of mixing a neutralizing reagent with the hazardous waste so as to cause the hazardous waste to have a pH of between 5 and 14. The neutralizing reagent is an alkaline material, preferably lime, hydrated lime, or calcium hydroxide. The sulfide is either sodium hydrosulfide or sodium sulfide. The process further includes the step of separating the pretreated waste containing the generated sulfides of the heavy metals from the supernatant portion of the liquid hazardous waste prior to the step of mixing the chemical reagent. The retarder of the chemical reagent is a monomeric polyalcohol. The accelerator is calcium chloride.

Kinetic-Spectrophotometric Determination of Tellurium (IV) by Its Catalytic Effect on the Reduction of Thionine by Sodium Sulfide in Cationic Micellar Medium

Abstract: A simple and highly sensitive method is proposed for the determination of Te(IV) by its catalytic effect on the reduction of thionine by sodium sulfide in the presence of cetyl trimethyl ammonium bromide as a micelle media The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of thionine at 600 nm with a fixed time of 05-25 min from initiation of the reaction Tellurium can be measured in the concentration range of 06-5000 ng/mL, with a limit of detection of 03 ng/mL Te(IV) The influence of more than thirty potential interfering ions was studied on the determination of tellurium The relative standard deviation for ten replicate measurements of 0020 and 500 ng/mL Te(IV) was 21 and 19%, respectively The method was applied for the determination of tellurium in synthetic samples