Showing papers on "Sodium sulfide published in 1973"

Removal of sodium chloride from pulp mill operations

Abstract: Sodium chloride is removed from pulp mill systems in which the smelt from the spent pulping liquor recovery operations contains sodium carbonate and sodium chloride, and optionally other components, depending on the pulp mill system. The smelt is made up into a hot aqueous solution thereof, and is evaporatively cooled to crystallize hydrated sodium carbonate, while avoiding deposition of sodium chloride. After separation of the crystallized sodium carbonate, and other crystallized salts, for example, sodium sulfide and sodium sulfate if a Kraft mill system is employed, the mother liquor is evaporated with heating to deposit sodium chloride in a substantially pure form. The sodium carbonate may be converted into an active pulping chemical for recycle, typically into sodium hydroxide by recausticization.

Impregnation of cellulosic pulp under superatmospheric pressure with waste alkaline oxygan gas bleaching liquor followed by oxygen-alkali bleaching

Abstract: 1. IN THE BLEACHING OF CELLULOSE PULP BY THE ALKALINE OXYGEN GAS PROCESS, IN WHICH A GAS CONTAINING OXYGEN IS INTRODUCED INTO THE PULP IN THE PRESENCE OF ALKALI, WHICH CAN BE SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE AND SODIUM CARBONATE AND WHICH OPTIONALLY MAY CONTAIN SODIUM SULFIDE, THE IMPROVEMENT WHICH COMPRISES FIRST IMPREGNATED UNDER SUPERATMOSPHERE PRESSURE CELLULOSE PULP OBTAINED FROM A CONTINUOUS PULPING OR DIGESTION PROCESS AND CONTAINING SPENT PULPING LIQUOR WITH WASTE ALKALINE OXYGEN GAS BLEACHING LIQUOR IN ORDER TO DISPLACE A MAJOR PORPORTION OF THE PULPING CHEMICALS FROM THE CELLULOSE PULP BUT RETAIN A MINOR PROPORTION OF SUCH CHEMICALS, AND THEN IMPREGNATING UNDER SUPERATMOSSPHERIC PRESSURE THE RESULTING PULP WITH ALKALI TO BE EMPLOYED IN THE ALKALINE OXYGEN GAS BLEACHING.

Synthesis and Substitution of 1,3,4,6-Tetra-substituted-3,6-dihalogeno-2,5-piperazinediones

Abstract: Addition of chlorine to 3,6-dimethylene- (3) and 3,6-dibenzylidene-1,4-dimethyl-2,5-piperazinediones gave isomers of the corresponding tetrachloride, and substitution of 1,3,4,6-tetramethyl-2,5-piperazinedione with bromine also gave tetrabromide (2) of the same type via successive elimination and addition reactions. Treatment of 2 with water and with methanolic sodium acetate gave the corresponding 3,6-dihydroxy and dimethoxy derivatives, respectively, while treatment with sodium iodide, sodium sulfide, sodium thiocyanate, or sodium thioacetate gave only 3 and sulfur in a good yield. Similar results were obtained in the case of octahydro-5H,10H-dipyrrolo[1,2-a: 1′,2′-d]pyrazine-5,10-dione. However, bromination of 6,13-dioxo-6a,7,13a,14-tetrahydro-6H,13H-pyrazino[1,2-a: 4,5-a′]diindole gave rise only to aromatization. Configurations of the isomers obtained and the reaction processes were discussed.

Hydrogen sulfide pretreatment of lignocellulosic materials in alkaline pulping processes

Abstract: DIRECTION OF THE SUPPORT TUBE (8) AND WHICH WHILE THE REACTOR IS IN OPERATION IS SUPPORTED ON THE LOCKING PLATE (5,6), AND WHILE THE REACTOR IS SHUT DOWN IS SUPPORTED ON THE SLEEVE TUBE (3) BY MEANS OF A PAWL DEVICE (14), THE LENGTH OF TRAVEL OF THE AUXILIARY TUBE (12) BEING SUCH THAT WHEN THE PAWL DEVICE IS IN OPERATION THE SUPPORT TUBE (8) IS AT LEAST PARTLY RELIEVE OF THE WEIGHT OF THE MODERATOR COLUMN. 1. IN AN ALKALINE PULPING PROCESS IN WHICH LIGNOCELLULOSIC MATERIAL IS PRE-TREATED WITH HYDROGEN SULFIDE, IN WHICH THE PRE-TREATED MATERIAL IS DIGESTED UNDER HEAT AND PRESSURE IN AN ALKALINE DIGESTING LIQUOR COMPRISING A SODIUM BASED DIGESTING AGENT TO FORM THE PULP, IN WHICH THE DIGESTED PULP IS SEPARATED FROM THE DIGESTING LIQUOR AFTER DIGESTION, AND IN WHICH THE DIGESTING LIQUOR IS PROCESSED FOR RECOVERY OF THE ALKALINE DIGESTING AGENT, THE IMPROVEMENT WHICH COMPRISES: PROVIDING FROM THE DIGESTING LIQUOR PROCESSED FOR RECOVERY OF THE ALKALINE DIGESTING AGENT, A HIGH SULFIDITY LIQUOR CONTAINING AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF SODIUM SULFIDE AND SODIUM HYDROSULFIDE AND HAVING A SULFIDITY OF ABOUT 75% TO 200% AND A WEIGHT RATIO OF SULFUR TO SULFUR PLUS SODIUM OF FROM ABOUT 0.35-0.58; CONTACTING THE LIGNOCELLULOSIC MATERIAL WITH SAID HIGH SUFIDITY LIQUOR IN A PRE-TREATMENT VESSEL PRIOR TO ALKALINE DIGESTION; INTRODUCING CARBON DIOXIDE GAS INTO SAID HIGH SULFIDITY LIQUOR IN SAID VESSEL, IN AN AMOUNT IN EXCESS OF STOICHIOMETRIC TO GENERATE HYDROGEN SULFIDE FROM SAID HIGH SULFIDITY LIQUOR; MAINTAINING THE TEMPERATURE IN SAID PRE-TREATMENT VESSEL WITHIN THE RANGE OF ABOUT 120 TO 165*C. FOR ABOUT 20 TO 200 MINUTES AND UNDER A PARTIAL PRESSURE OF HYDROGEN SULFIDE GAS OF ABOUT 10 TO 80 P.S.I. TO EFFECT REACTION BETWEEN HYDROGEN SULFIDE AND THE LIGNOCELLULOSIC MATERIAL IN SAID PRE-TREATMENT VESSEL TO INCREASE PULP YIELD OVER THAT OBTAINED BY AN ALKALINE PULPING PROCESS IN WHICH THE LIGNOCELLULOSIC MATERIAL IS DIGESTED IN SAID ALKALINE DIGESTING LIQUOR; SEPARATING PRE-TREATED LIGNOCELLULOSIC MATERIAL FROM THE ACCORDING TO WHICH THE SUPPORT TUBES PASS THROUGH THE BOTTOM OF THE REACTOR VESSEL AND ARE PROVIDED AT THE OUTER END WITH AT LEAST ONE PLUG WHICH ACTS AS A RADIATION SHIELD AND A COOLING-GAS SEAL, IN WHICH THE SUPPORT TUBE (8) IS FIXED IN A SLEEVE TUBE (3) BY MEANS OF A LOCKING PLATE (5, 6) SUCH THAT BETWEEN THE SUPPORT TUBE (8) AND THE SLEEVE TUBE (3) THERE IS AN ANNULAR GAP (11) CONTAINING AN AUXILIARY TUBE (12) WHICH IS MOVABLE IN THE AXIAL

Process for producing faujasitic-type crystalline zeolites

Abstract: Faujasitic-type crystalline zeolites X and Y are produced. In one embodiment, sodium sulfide is added to the reaction mixture as a source of sodium and as a buffer. The buffering action of the sodium sulfide provides the basicity required to maintain the alumina hydrate component of the reaction mixture in solution but not a basicity whereby zeolite crystallization is retarded. In another embodiment, a nucleating mixture having the formula 3-10 Na2 S: 5-15 Na2 O: 5-50 SiO2 : 0.4-4.0 Al2 O3 : 50-500 H2 O is added to the reaction mixture to promote crystalline zeolite formation.

Solubilities of Pb + 2 , Bi + 3 , Sb + 3 , and Cu + 1 sulfides in (NaCl+KCl+Na 2 S) melts

Abstract: Solubilities of common metal sulfides have been determined in the (NaCl+KCl) eutectic melt with and without Na2S. A novel gas-phase equilibrium technique has been used for PbS, Bi2S3, and So2S3, and an improved liquid phase equilibrium technique for Cu2S, which eliminates the errors due to physical entrapment of the sulfide phase and segregation on quenching, enabling precise measurements to be made. Solubilities in the (NaCl+KCl) eutectic melt were determined as a function of temperature in the rante 700° to 950°C, and were found to be small. The partial molar heats of mixing of the sulfides in the eutectic melt have been calculated from the solubility measurements, to be 13.3, 31.4, 37.1, and 49.0 kcal for PbSs), Sb2S2(l), and Cu2S(s), respectively. Sodium sulfide addition was observed to enhance these solubilities, the effect being largest for Cu2S followed by Sb2S3, Bi2S3, and PbS. This effect is explained qualitatively. It was observed that PbS and Sb2S3 obey Henry's law up to saturation in (NaCl+KCl+Na2S) melts.

Method of purifying air containing mercury vapor

Abstract: A method for the removal of mercury vapor from air containing same which comprises introducing the air into the top of a first chamber which is larger at its top than at its bottom and subjecting the air therein to a spray of aqueous sodium sulfide solution. The liquid is thereafter collected along the small floor of this chamber in a tank from which the sodium sulfide solution is recirculated to the spray. The air is induced to flow in an undulating path around vertical baffles and through droplet or mist filters which trap (hold back) any residual droplets before being released to the atmosphere.

Coal gasification process

Abstract: A process for coal gasification whereby coal is converted to carbon monoxide, hydrogen and other gaseous products by contact with molten sodium sulfate, said sodium sulfate being reduced to sodium sulfide, which is regenerated with oxygen to sodium sulfate to provide a cyclic process.

Process for purifying industrial gases containing hydrogen sulfide with sulfur production

Abstract: Process for purifying industrial gases containing hydrogen sulfide and for simultaneously producing elemental sulfur, comprising contacting said gases with an aqueous solution of sodium hydroxide and/or sodium carbonate, thereby forming a sodium sulfide solution, contacting said solution with an aqueous solution of ammonium hydrogen carbonate or with a gaseous mixture of CO2 and NH3 so as to precipitate sodium hydrogen carbonate, decomposing the latter to CO2 and neutral sodium carbonate which is recycled, heating the resulting liquid phase to produce NH3 and H2 S and producing sulfur by reacting the H2 S with sulfurous anhydride.

Toxicity of sodium sulfide to common shiners dynamic bioassay

Abstract: Common shiners, Notropis cornutus (Mitchill), were exposed to sodium sulfide in concentrations from 0.33 to 3.95 ppm. A dynamic bioassay procedure was used in order to prevent oxygen depletion in test aquaria and to continually expose the test organisms to fresh chemical. Dilution water was purified by a reverse osmosis unit and did not vary chemically. Dilution water and the test solution (mixed at 300 ppm sodium sulfide) were delivered separately by two mechanical proportioning pumps into 12 aquaria. Median tolerance limits (TL50) were calculated for 24, 48, and 96 hr. They were 2.68, 1.72, and 1.64 ppm, respectively. These figures are approximately one-half of the TL50 values for static bioassays. The apparent decrease in TL50 may be partly attributable to the instability of the sodium sulfide in solution, and the true TL50 values may be somewhat lower than even the measured dynamic values. The observed instability of sodium sulfide would also emphasize the need to consider the extent of conversion or removal of such materials by natural processes when setting ambient river standards.

Synthesis and substitution of 1,3,4,6-tetra-substituted-3,6-dihalogeno-2,5-piperazinediones

Abstract: Addition of chlorine to 3,6-dimethylene- (3) and 3,6-dibenzylidene-1,4-dimethyl-2,5-piperazinediones gave isomers of the corresponding tetrachloride, and substitution of 1,3,4,6-tetramethyl-2,5-piperazinedione with bromine also gave tetrabromide (2) of the same type via successive elimination and addition reactions. Treatment of 2 with water and with methanolic sodium acetate gave the corresponding 3,6-dihydroxy and dimethoxy derivatives, respectively, while treatment with sodium iodide, sodium sulfide, sodium thiocyanate, or sodium thioacetate gave only 3 and sulfur in a good yield. Similar results were obtained in the case of octahydro-5H,10H-dipyrrolo[1,2-a: 1′,2′-d]pyrazine-5,10-dione. However, bromination of 6,13-dioxo-6a,7,13a,14-tetrahydro-6H,13H-pyrazino[1,2-a: 4,5-a′]diindole gave rise only to aromatization. Configurations of the isomers obtained and the reaction processes were discussed.