| In the growing process of global population, the fertilizer industry for the protection of grain per capita is identitied by people. While with the people requireing to improve the quality of life and the living environment, eco-functional fertilizers are pursuited by peoples. Eco-functional humic acid fertilizers can not only provide the nutrients which are needed by crops for their growth but also enhance their resistance. But now the production process of eco-functional humic acid fertilizers are still having some problems should be solved, such as the raw weathered coal activation, the low content of water-soluble humic acid in humic acid fertilizers which is readily absorbed and take large physiological effects on crops, the method chosen to analyse water-soluble humic acid in humic acid fertilizers and so on. This paper is prepared to solve these problems.In the study of humic acid liquid fertilizer, humic acid aqueous is prepared by H2O2 as oxidant to oxidation-ammonification the weathered coal, the results show that the presence of H2O2 can improve the content of regeneration humic acid and humic acid ammonium content in liquid products with the increased the amount of H2O2. The study of this part also shows that the addition of ammonium bicarbonate is not conducive to oxidation-ammonification of weathered coal by H2O2. Through the single factor experiment on oxidation-ammonification of weathered coal by H2O2 we can determine the suitable mixture ratio (mass ratio), weathered coal:25% ammonia: 30% hydrogen peroxide:water= 1:1.04:1.5:6.46; and suitable reaction conditions, reaction temperature 60℃, weathered coal particle size less than 0.149mm, reaction time 60min. On this basis, the study of this part also through response surface method (RSM) experiment to optimize the oxidation ammonifica-tion of weathered coal by H2O2. Through the response from the experimental data value we conclude the quadratic regression model which is: Y=24.52＋0.97×X1-0.12×X2＋0.27×X3-0.03×X4＋8.52×10-3×X1×X2-2.02×10-3×X1×X3＋3.44×10-3×X1×X4＋3.23×10-3×X2×X4-2.18×10-3×X3×X4-0.04×X12-5.42×10-3×X22Analyzed by the regression equation we can predict the optimum conditions of oxidation-ammonification of weathered coal by H2O2, the weathered coal consump-tion 10.00g, weathered coal particle size less than 0.149mm, the amount of ammonia 13.68g, hydrogen peroxide dosage of 8.56g, deionized water 67.76g, reaction temperature 80℃, reaction time of 40min, then the maximum of Y value is 44.7013g. Experimental results show that the regression model forecasts are reliable. In addition the fitting equation also shows that the amount of ammonia (Xi) and the reaction temperature (X3) are the most important two factors to affect the oxidation-ammonification of weathered coal by H2O2. Through the evaluation of oxidation-ammonification of weathered coal by H2O2, the presence of H2O2 is conducive to the reaction of weathered coal degradation to humic acid ammonium. Through the study of oxidation-ammonification of weathered coal by H2O2 before and after the change condition, we obtain the mechanism of the reaction that is in the reaction of weathered coal oxidation-ammonification by H2O2, the humic acid's methoxy-fracture structure was tattered and formed more carboxyl, which can be combined with more ammonia.In the study of this part, the preparion of liquid humic acid fertilizer are studyed from the selection of raw materials and production processes, the other aspects are also studyed. In preparation of liquid humic acid fertilizer, humic acid ammonium aqueous solution is made by oxidation-ammonification of weathered coal by H2O2. The humic acid prepared by this method has soluble in water, permeability, easy absorbed by crops and so on. In order to facilitate guidance of liquid humic acid fertilizer production, the study also drawn 0℃, CO(NH2)2-NH4H2PO4-KCl-humic acid ammonium water solubility of the grain boundary curve analysis through the experimental.In the study of humic acid compound fertilizer, the paper first study the preparation of water-soluble humic acid sodium from highly calcium and magnesium weathered coal, the results show that the addition of surfactants and can increase the content of water-soluble humic acid sodium in products. From the experimental we determine the suitable preparation conditions of water-soluble humic acid sodium from highly calcium and magnesium weathered coal which are weathered coal consumption 10.Og, weathered coal particle size less than 0.150mm, SDS dosage 0.6%, NaOH content 20%, Na2CO3 dosage 30%, liquid to solid ratio is 1.2, the reaction temperature is 70℃, the reaction time is 160min, under this optimum conditions the content of water-soluble humic acid sodium in the products is 29.47% (dry basis). On this basis, the paper has also studied the preparation of humic acid compound fertilizer, the analysis of the humic acid in compound fertilizer and humic acid compound fertilizer's controlled release performance test, the results show that the release of nitrogen in humic acid compound fertilizer similar to "S" shape, that is the humic acid compound fertilizer having a certain slow/controlled-release capability. |
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