| ABSTRACT:Antimony thioantimonate(SbSbS4), a excellent extreme-pressure and anti-wear lubricant additive, can significantly improve weld point, load capacity and decrease the friction cocefficient of grease, it’s wildely used in mining machinery, shipping and military equipments. it In this article, Sb2O3powder, sulfur, Na2S·9H2O, NaCl and tartaric acid(C4H6O6) as raw material, solution of sodium thioantimonate(Na3SbS4) and antimony(III) tartrates complexes was prepared respectively, then two kinds of solution will be mixed to synthesize the antimony thioanimonate by aqueous precipitation method.Sodium thioantimonate was prepared via antimony trioxide powder reacting with a red polysulfide solution which was a product of elemental sulfur dissolving in aqueous sodium sulfide. Effect of temperature, ratio of liquid to solid, dosage of sodium sulfide and elemental sulfur, reaction time and concentration of sodium hydroxide, crystallization temperature on yield and dissolved quantity of sodium thioantimonate were systematically studied respectively. The results show that yield of Na3SbS4increase with the decrease of ratio of liquid to solid, however, yield gradually increase then become flat with the increase of dosage of Na2S. yield of sodium thioantimonate up to96%by controlling liquid-to solid ration, excess dosage of sodium sulfide and elemental sulfur was6mL/g,20%and5～10%respectively by reacting for30minutes under80℃. Sodium thioantimonate was recovered by crystallizing the filtrate at low temperature and founded that dissolved quantity of sodium thioantimonate decrease with the increase of sodium hydroxide concentration, fastly increase, however, with the increase of temperature, The chemical formula of sodium thioantimonate solid obtained at5℃was Na3SbS4·9H2O with a cubic crystal form.Based on the thermodynamics principle, the hydrolysed products of antimony trichloride solution at neutral condition was analysed, the results indicated that antimony chloride solution will completely hydrolyzed to Sb4O5C12and SbOCl at pH1.5～2.5. However, a solution stable at pH6.5～11.85was obtained when molar ration of tartaric to antimony limited to1.7～2.1and concentration of Sb3+was less than80g/L. Infrared spectrum, DSC-TGA and acid-base titration methods were employed in the analysis of complex solution and it’s crystal, results indicated that the complex crystal have a binuclear quadridentate structure and can be represented by Na2Sb2(C4H2O6)2·H2O, Sb3+simultaneously coordinated the oxygen atom from carboxyl and alcohol group of tartaric acid; Tartrate ion react with Sb3+to produce the [C4H2O6-Sb-OH]2-complex at neutral solution. On the basis, the complex solution was prapared by Sb2O3powder reacting with a mixed solution of C4H6O6and NaCl. Effect of the dosage of tartaric acid, concentration of chloride ion, temperature, reaction time and liquid to solid ratio on leaching rate of antimony trioxide powder was researched, the results indicated that tartaric acid has a lower-capability to leach antimony trioxide powder, but the leaching rate was significantly improved by adding NaCl into the solution; When the molar ratio of C4H6O6to Sb2O3was4, leaching rate increase with increasing temperature and the concentration of chloride ion, but the complex solution will partially hydrolyzed to Sb4O5Cl2when the concentration of chloride ion below2mol/L and temperature was higher than70℃. Sb2O3completely dissolved in30minnutes and hydrolysis reaction can be eliminated when the concentration of NaCl was3mol/L, temperature at the range of40℃and the ratio of liquid to solid was8mL/g.A specific concentration solution of Na3SbS4·9H2O, which prepared using recrystallized sodium thioantimonate,was pumped into a neutral antimony tartrate complex solution to prepare antimony thioantimonate. Effect of pH,temperature,concentration and washing on yield and the content of antimony of SbSbS4was studied. The results indicated that yield of SbSbS4decrease with increasing pH; antimony content of SbSbS4was slightly improved by increasing temperature and decreasing the concentration of reactants. Antimony thioantimonate prepared at pH6.5～8.0under ambient temperature was washed by deionized water and the contents of antimony and sulfur of the product was65.38%and34.26% respectively by controlling Sb3+/[SbS4]3-was1:1and the aqueous antimony concentration of antimony complex was65g/L. pariticles of SbSbS4was well-distributed by adding PVP and a excellently hydrophobic property was obtained by adding CTAB in the praparation process. Finaly, hydrophobic SbSbS4was evenly mixed with lithium-based grease then, the friction coefficient and oil film strength of the grease was tested, the results show that the oil film strength was improved form598N to1048N and the frication coefficient can be decreased from0.0823to0.0694when the mass fraction of animony thioantimonate was2.0%in0#lithium-based grease. On the other hand, oil film strength and fraction coefficient was1048N and0.0703when added a mixture which mass fraction was3.0%and the mass ratio of WS2to SbSbS4was1:2in2#lithium-based grease, results show that SbSbS4has excellent Extreme-Pressure and antiwear performance, as well as a favourable synergistic effect with WS2.公式105条,图45幅,表22个,参考文献90篇... |
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