Research On Design Structure,Syntheses And Slurry Stability Of Ddispersant Based On Humic Acid Of CWS

In order to improve the stability of boertai coal pulping,this paper analyzes the structural characteristics of boertai coal,selects humic acid as the research object,modifies it to obtain the structure of dispersant matching with the coal,and synthesizes the designed dispersant through experiments.Compared with the other two dispersants with similar hydrophobic end structure,their pulping stability was studied.The structure model of coal and humic acid was constructed by various methods:the proportion of each element was determined by element analysis,in which N and S elements were not specifically explored;the carbon skeleton structure including benzene ring and connecting branch chain was determined by NMR carbon spectrum;the relative content of each carbon containing functional group was determined by XPS peak fitting;the substitution mode of each benzene ring was determined by IR peak fitting Further,the functional groups are connected with the carbon skeleton structure.Materials Studio(MS)was used to optimize the structure of the model,and the optimized structure of the ball stick model was obtained.Then the adsorption calculation of the optimized results was carried out by using adsorption ractor module,and the structure of dispersant matching with coal was designed through the calculation results.According to the designed dispersant structure,the target product was synthesized by two-step reaction.The first step of sulfomethylation: according to the experience,the reaction temperature is 80 ? and the reaction time is 2.5 h.The optimum molar ratio of formaldehyde to sodium sulfite was 1:5.The second step of graft copolymerization was six factors and five levels orthogonal experiment L25(56)with acrylic acid,allyl polyethylene glycol,initiator,time,temperature and a blank factor Taking the fluidity and stability as the index,the stability as the important object,the fluidity as the secondary object,the comprehensive score method with the weighted score as the index,and the comprehensive balance method as the analysis method to determine the optimal scheme,the optimal experimental conditions were obtained as follows: acrylic acid 0.3g,allyl polyethylene glycol 0.9g,initiator 2%,reaction time 3h.The reaction temperature is 80 ?.The slurry prepared under the optimal scheme had high stability and good fluidity,and the product was characterized by infrared spectrum.Sodium naphthalenesulfonate,sodium lignosulfonate,synthetic sodium humate sulfonate and modified sodium humate sulfonate with hydrophobic end of benzene ring structure were used for pulping,and the mechanism was analyzed.The stability of slurry was characterized by water separation rate,and the reason of stability was explained by viscosity and fluidity.The stability was analyzed by adsorption isotherm curve,zeta potential and contact angle.The results showed that sodium naphthalene sulfonate had the best fluidity,the lowest viscosity,but the worst stability.Sodium lignosulfonate and sodium humate sulfonate were in the middle level in terms of fluidity and stability,while modified sodium humate sulfonate was not as good as the former in terms of fluidity,but still had good fluidity,good viscosity reducing ability at high shear rate,and good stability The results showed that: when the addition amount was 0.4%and the pulp concentration was 62%,the water separation rate was only 2.38%;through the adsorption experiment,the KL value of sodium naphthalene sulfonate was the largest,the adsorption capacity was the strongest,followed by modified sodium humate sulfonate and sodium humate sulfonate,and the sodium lignosulfonate was the weakest;the surface wettability of coal particles modified by reaction dispersant was as follows:modified sodium humate sulfonate better than sodium naphthalene sulfonate better than sodium humate sulfonate better than lignosulfonate Among them,the contact angle between sodium naphthalenesulfonate and modified sodium humate is small,the wetting ability is strong,and the wetting effect of sodium lignosulfonate and sodium humate is poor;zeta potential directly reflects the stability,in which modified sodium humate has the largest electronegativity,followed by sodium lignosulfonate and sodium humate,and sodium naphthalenesulfonate is the highest,which proves the structure The rationality of the introduction of carboxylic acid chain and polyethylene glycol chain plays an important role in the stability.There are 49 pictures,30 tables and 91 references in this thesis.