Vapor phase reduction of lead sulfide. by E.R. Cole, Jr., W.M. Dressel, and M.M. Fine.

Publisher: Dept. of the Interior in Washington

Written in English
Published: Pages: 11 Downloads: 73
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Lead acetate test paper is generally regarded as selective for detection of hydrogen sulfide (ASTM ). Hydrogen sulfide reacts with lead ions from the lead acetate to form solid lead sulfide PbS, a black solid. H 2 S + Pb 2+ → PbS + 2H + Hydrogen sulfide is released in the first few seconds after wool begins to burn (Spurgeon et al. ). Hydrogen Sulfide (H 2 S). DESCRIPTION (Hydrogen Sulfide): Hydrogen sulfide is a colorless, flammable gas with an offensive odor. It is a considered a toxic gas shipped in steel cylinders as a liquefied gas under it's own vapor pressure of approximately psig @ 70° F. Typical it is used as a reagent for chemical analysis, an additive for oils and in the preparation of metallic sulfides. Carbonair offers a full line of granular activated carbon and other vapor phase specialty media that can be applied in water treatment applications including virgin coal-based activated carbon (granular and pellets), virgin coconut based activated carbon, reactivated carbon and impregnated activated carbons for treatment of sulfur compounds, mercury, ammonia and amines. reflow provides an advantage in limiting the maximum temperature on the PCA to the vapor temperature of the heating fluid. Vacuum applied in the vapor phase process allows for reduction in the amount of voiding found. The reliability of vapor phase with and without vacuum is not well known and the objective of this study was to evaluate this.

• It is difficult to use a vapor-phase organic reactant when the electrodes are immersed in liquid electrolyte 4. The requirement of having two reactions in an organic electrochemical reactor (an oxidation reaction at the anode and a reduction reaction at the cathode), where one reaction is often unwanted and where the product(s) of this. sulfide concentration may be below risk -based inhalation standards. Exposure to hydrogen sulfide can lead to rapid olfactory fatigue or p aralysis. W ith continuous low -level exposure, a person loses the ability to smell the gas even t hough it is still present. At high concentrations, thi s . S is considered “non- persistent.” Vapor: minutes to hours; liquid: rapidly evaporates at ambient temperatures and pressures. Persistence will depend upon amount and purity of the agent, method of release, environmental conditions, and the types of surfaces and materials impacted. RE INTRODUCTION OF VAPOR PHASE SOLDERING TECHNOLOGY FOR LEAD FREE APPLICATION. Adzahar Samat and KL Chia. Venture Corporation Limited. Singapore. ABSTRACT. Vapor Phase soldering is a method of reflow technology developed by ATT Labs in NJ back in the 80s. Then, Vapor Phase soldering was the preferred reflow soldering.

Lead reacts vigorously with fluorine, F 2, at room temperature, and chlorine, Cl 2, when heated, forming the corresponding lead(II) halides [8]. Pb (s) + F 2 (g) PbF 2 (s) Pb (s) + Cl 2 (g) PbCl 2 (s) Lead(II) is precipitated by chloride, bromide and iodide ions under cold neutral to acidic conditions. Hydrogen sulfide was trapped by passing the sparge gas through 5 ml of N NaOH above a fine sintered glass disk. Negligible sulfide was collected in a second similar trap in series, demonstrating the efficiency of collection. The volume of sparge gas was measured by displacement rather than by .

Vapor phase reduction of lead sulfide. by E.R. Cole, Jr., W.M. Dressel, and M.M. Fine. Download PDF EPUB FB2

Removal of lead and zinc and the production of prereduced pellets from iron and steelmaking wastes. Author Dressel, W. (Waldemar M.) Published. The pbs vapor was transported by the inert carrier gas to the reduction zone of the furnace where it was reduced at the same temperature with excess hydrogen to metallic lead.

Lead of Pct purity was produced. The h2s formed can be decomposed into elemental sulfur and water vapor by. The kinetics of vaporization of lead sulfide were investigated in the temperature range to °C using a thermogravimetric balance.

The effect of nonreactive ambient atmosphere on the vaporization kinetics was examined in some detail. Under He-rich He-N2 atmosphere the rate of vaporization was found to be about four times as large, as that under by:   Uncatalyzed reduction kinetics of lead sulfide with CO-COrN3 gas nsixtures in presence of lime at C; reproducibility runs at.P~0 = 14 atm.

u 10 20 30 40 50 Reduction of lead sulfide with gas mixtures in the presence of lime (a) (Jncatalyzed experiments The weight loss data for the uncatalyzed reduction of And M.M.

Fine. book mixtures with CO Cited by: 3. It clearly shows that a higher vapor pressure tends to be obtained in a matrix where the formation of metallic Pb is favored; while for a sample having lower FeO content and lower w(Fe2+)/w(Fe3+) ratio (the formation of metallic Pb is prohibited), an increase in temperature is more effective to promote the evaporation of lead.

Effect of. Wait until all of the lead sulfide has thermally decomposed, by monitoring the reaction details window associated with the gas tube. To open the reaction details, hold the mouse over the gas tube and click on the light blue "i" icon.

To reduce the lead oxide (product of thermal decomposition) leave the Bunsen burner on and turn on the hydrogen. measure total vapor phase mercury (Hg), was carried out at two coal-fired power plants. The objective of And M.M. Fine. book purpose of CAMR was to achieve a 70% reduction in nationwide Hg mass emissions from coal-fired electricity generation units (EGUs) by CAMR would have re.

SMT- Vapor Phase Soldering: The Comeback Kid. Vapor phase soldering (VPS), also known as condensation soldering, has gone through changes in popularity.

It was the process of choice in the early s, but its use declined considerably for two reasons: problems with the VPS process itself and improvements in IR processes. Vapor Phase soldering was the process of choice in reflow soldering as it provided the easiest way of heat transfer for the newly developed SMD technique.

The soldering of SMT boards was very convenient when using Vapor Phase because of its excellent heat transfer capabilities. The vapor phase ovens were pretty long and heavy though. W.M. Dressel M.M. Fine A lead smelting process that appears to present minimal pollution problems has been developed at the Bureau of Mines, Rolla Metallurgy Research Center.

mated that a typical concentration of lead in urban refuse is ppm [4]. While Federal and California regulations limiting averaged (3-month) concentrations of lead to g/m3 in ambient air are generally met [5], point sources which can cause locally unhealthy conditions are still a cause for concern [6].

In combustion systems, lead and. Lead sulfide crystallizes in the sodium chloride motif, unlike many other IV-VI semiconductors. Since PbS is the main ore of lead, much effort has focused on its conversion.

A major process involves smelting of PbS followed by reduction of the resulting oxide. Idealized equations for these two steps are: 2 PbS + 3 O 2 → 2 PbO + 2 SO 2.

Vapor Phase Soldering - The principle of vapor phase soldering rests on the fact that with condensed vapor thermal energy can be transferred. In the electronic industry, this principle is being used to transfer thermal energy to PCB assemblies, soldering them in a reflow-type process.

On the medium, the vapor, special demands are placed. It may not lead to any corrosion, not be electrically. E R SCHEURING RED MAPLE OCKLAND OLDMARTIN L E D G E VI E W GRANT GEORGE L A W R E N C E C T H P P R Y A N C HI C A G O E R I E N Reduction of SO4 2-to S2-Inert Anaerobic Zone Diffusion of SO4 Diffusion of S2-S2-HS-H 2S Sulfide Generation Vapor phase concentrations determine odor and corrosion impacts.

hydrogen sulfide with lead acetate. The initially white lead acetate turns brown when exposed to hydrogen sulfide in the presence of water. The greater the amount of H 2 S in the sample, the darker the stain that forms on the tape. Lead acetate is impregnated onto a roll of paper tape that is installed in the analyzer.

Only a small portion of S. Vapor Phase Reflow Soldering is an advanced soldering technology. This is fast replacing other forms of soldering processes manufacturers presently use for assembling printed circuit boards in high volumes for all sorts of electronic products.

Soldering electronic components to printed circuit boards is a complex physical and chemical process requiring high temperatures. Thermal Decomposition and Reduction of Lead Sulfide; Thermal Decomposition and Reduction of Lead Sulfide.

Added by Sam Holyman on This model first shows the thermal decomposition of lead sulfide into lead oxide. Hydrogen gas is then used as the reducing agent to liberate the lead from the lead oxide.

The fine print. This is a research and information site. All of the information on this site has been gathered and submitted by the players and Niami Denmother. While we try our best to keep the information here as accurate and up to date as possible, rely upon it at your own risk.

"The purpose of this investigation is to determine the vapor pressure or volatility of the sulfides of the following metals by Langmuir's method: a) Zinc b) Cadmium c) Mercury d) Manganese e) Tin f) Lead g) Arsenic h) Antimony i) Molybdenum J) Iron k) Cobalt l) Nickel m) Copper n) Silver o) Calcium p) Aluminum.

The relation of this property to the position of the metals in the periodic table. Lead(IV) sulfide is a chemical compound with the formula Pb S material is generated by the reaction of the more common lead(II) sulfide, PbS, with sulfur at > °C and at high pressures. PbS 2, like the related tin(IV) sulfide SnS 2, crystallises in the cadmium iodide motif, which indicates that Pb should be assigned the formal oxidation state of 4+.

Liquid Phase The sample that is treated in accordance with the method. Residual fuel oils that contain H 2S in the liquid phase can result in hazardous vapor phase levels of H 2S in storage tank headspaces.

The vapor phase levels can vary significantly according to the. Frc. I Schematic phase relations in the condensed Cu-Pb-S system at 'C. The reduction in size of the two-liquid fields and the appearance of Pbs, ccu", and Cu result in phase relations at oC as shown in Figure 2.

At 'C the central sulfide liquid is reduced to a small four-sided area. Goodwin, R.D., Hydrogen sulfide provisional thermophysical properties from to K at pressures to 75 MPa, Report, NBSIR; NTIS No. PB, pp., [.

Lead(II) sulfide is a black solid. It does not react with acids. It reacts with air at a high temperature to make lead(II) oxide. It is one of the least toxic forms of lead. This does not mean that it is not toxic, though. It is the result of a test for hydrogen sulfide.

Paper soaked in lead(II) acetate is passed through hydrogen sulfide. Phase I ESA was completed by MAI Environmental in July [2]. The objective of the Cottage Road Site investigation was to collect data to evaluate whether contamination at the Site results in significant vapor intrusion risk and the implications relative to Maine DEP vapor.

Lead Sulfide / Lead Sulphide (PbS) TSCA (SARA Title III) Status: 1) Listed. For further information please call the E.P.A.

at 2) Product safety data from NIOSH Lead Sulfide / Lead Sulphide (PbS) CAS Number: CAS# Dr. Myron Rubenstein, Ph.D (Polytechnic University of Turin, Italy) Lead Sulphide Quantum Dots has shown some novel and excellent optical and electronic properties, such as IR photodetectors, photovoltaics, electroluminescence, photoluminescence, thermal and biological images and display devices.

The photoluminescence (PL) spectra of PbS QDs with different particle sizes, being quantum. Lead sulfide is an inorganic compound with the chemical formula PbS. It is also known as galena, which is the principal ore and important compound of lead. It is one of the earliest materials to be used as a semiconductor as it tends to crystallize in sodium chloride.

Lead sulfide is toxic if it is heated to decomposition, which forms lead and. Symbols used in the table of constants; Symbol Meaning; State: electronic state and / or symmetry symbol: T e: minimum electronic energy (cm-1): ω e: vibrational constant – first term (cm-1): ω e x e: vibrational constant – second term (cm-1): ω e y e: vibrational constant – third term (cm-1): B e: rotational constant in equilibrium position (cm-1): α e: rotational constant – first.

Sulfides are compounds derived from the sulfide anion, S As sulfur is a member of group 16 on the periodic table, it is considered a chalcogen, and sulfide compounds belong to a class of compounds known as chalcogenides.

The bonding in transition metal sulfides is highly covalent, a property that is intimately related to their ability to function as semiconductors and pigments. These are. partitioning of lead relative to soil particle size.

The results of these tests, expressed as percent reduction of total lead, are presented in Table 2. The data indicate that limited removal of lead occurs, particularly in the course and medium fractions.

The concentration of TCLP-leachable lead also was significantly reduced, as shown in Table 3.Lead(IV) sulfide, PbS 2, containing lead in the +4 oxidation state; This set index page lists chemical compounds articles associated with the same name.

If an internal link led you here, you may wish to change the link to point directly to the intended article. This page was last edited on 19 February.Figure 6. Heavy Metal Reduction System - Process Flow Diagram. Figure 6 is a process flow diagram of a continuous flow through sulfide precipitation system that would be suitable for flows from 1 GPM to over 1, GPM with influent metals loading of 10ppm to ppm (or higher).