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.

Nonpoisonous treatment of chromium slag and extraction of calcium and magnesium

Abstract: Chromium slag is extracted by HCl, reducing agent is added to reduce Cr+6 to Cr+++, and then, from the ertract, calcium and magnesium are recovered, so as to comprehensively utilize the chromium slag. The prior art, heated sodium sulfide reducing method, may be replaced by the method of the present invention which has the merits of having the ability to treat large amount of slags with complete obviation of poisonous chromium.

Removal of dissolved chelates from aqueous solutions

Abstract: At least a portion of any iron, copper, nickel and chromium ions are removed from an aqueous liquid in which they are in solution as chelates of an alkylenepolyamine polyacetic acid or salt by (a) adjusting the pH of the liquid to above about 10; (b) adding sufficient sodium sulfide to react with at least a portion of the copper ions; (c) separating precipitated iron and copper compounds; (d) adding nitric acid to adjust the pH to the range of about 6 to 8; (e) adding sufficient sodium nitrite to the liquid to react with at least a portion of the nickel and chromium present; (f) heating the liquid to above about 575°F (302°C) for at least about 15 minutes to facilitate precipitation of nickel and chromium; and (g) separating precipitated solids to leave a non-hazardous filtrate.

Production of aromatic sulfide polymer

Abstract: PURPOSE:To obtain, an aromatic polymer having high molecular weight and useful as a heat-resistant resin in high reproducibility by reacting a dihalogenated aromatic compound in an organic solvent with an alkali metal sulfide such as anhydrous NaS produced by the solid-phase conversion dehydration of hydrated NaS crystal. CONSTITUTION:A dihalogenated aromatic compound (e.g. p-dichlorobenzene) is made to react with an alkali metal sulfide in an organic solvent (e.g. N- methylpyrrolidone) in the presence of 0.2-2.5mol of water (based on 1mol of sulfur atom in the reaction system) under agitation while sufficiently replacing the system atmosphere with nitrogen and keeping the reaction temperature at 240 deg.C for 2hr. The obtained slurry is poured into water and the precipitate is separated, washed and dried in a vacuum drier at 80C for a night to obtain the objective aromatic sulfide polymer having high molecular weight and excellent heat-resistance and useful as an electronic parts, automobile parts, etc., in high reproducibility. The alkali metal sulfide to be used in the above process is e.g. anhydrous sodium sulfide produced by the solid-phase conversion dehydration of hydrated sodium sulfide crystal.

The comparison of acid and enzymatic hydrolysis of pulp obtained from poplar wood (Populus sp.) by the Kraft method.

Abstract: This paper compares the acid and enzymatic hydrolysis in relation to bioethanol production. The pulp obtained from wood of the fast-growing poplar species (Populus deltoides x maximowiczii and Populus trichocarpa Torr. & A. Gray ex Hook) was used as a feedstock. The delignification process by the Kraft method was carried out with 19% and 26% of active alkali (NaOH and Na2S). The obtained sugars (xylose and glucose) were analyzed by a high-performance liquid chromatography. The results concluded that the enzymatic hydrolysis process is better than acid hydrolysis because a higher content of sugars (especially xylose) was obtained. Additionally, after the acid and enzymatic hydrolysis process from Populus trichocarpa pulp, more sugars were obtained than from the pulp of Populus deltoides × maximowiczii. The Kraft pulp from the wood of fast-growing poplar species is a good raw material for the production of glucose. However, in order to obtain a higher xylose content and finally increase the profitability of bioethanol production, a new method should be developed, or the Kraft method should be optimized.