Study On Preparation Of Granular Soil Modifier And Its Disintegration

Soil is the foundation of human survival,there are many soil problems emerging in recent years,which severely restrict the sustainable development of agriculture.Soil conditioner is often used to regulate barrier soil,however the powder modifier exist many problems in the process of actual use,such as difficult to throw uniformly,easy to produce dust hazard,and can not be carried out quickly in accordance with the proportion of allocation in actual situation.Therefore,it is important to solve the problems in the practical use of the powder modifier.In this research subject,the influence factors of granulation process of powder modifier are studied by the disc granulator,and some related factors influencing the disintegration process of granular modifier are discussed through the disintegration instrument.The purpose is to prepare a certain intensity of the granular soil conditioner,and ensure the granular soil conditioner can disintegrate rapidly under the influence of water.In this way,barrier soil can be improved.The main research conclusions are as follows:1、After the grinding treatment,the characteristic particle size of phosphate rock powder is decreased and the specific surface area of phosphate rock powder is increased.Some particles will be reunited in this process.With the extension of milling time,the available phosphorus content of phosphate rock powder is increased,three main mineral phase of the phosphate rock powder,such as fluorine apatite,quartz and hydroxyapatite,have decreased in the characteristic peaks of diffraction intensity.It indicates that the crystallization degrees of mineral are reduced.2、The granulating rate and qualified rate of powder modifier increase with the increase of the rotating speed of the disk,and both of them firstly increase and then decrease with the increase of the disk inclination and the amount of water.When the rotating speed is 35 r/min,the dip angle is 60 ° and the water content is 35%,the granulation effect is best,granulating rate and qualified rate are 83.34%,69.59% respectively;As for granulation effect,phosphate rock powder and dolomite are better than zeolite and organic fertilizer;The granulating rate increases when the fineness of phosphate rock powder become smaller and decreases when the content of zeolite become more;The granulating rate increases when the amount of attapulgite is bigger.And besides,the quantity of bentonite does not affect the result of the granulation;When the content of attapulgite,starch and polyvinyl alcohol all are 10%,starch and polyvinyl alcohol have better granulation effect when compared with attapulgite,and has a significant difference,the granulating rate are increased by 10.40% and 21.05% respectively.3、The fineness of phosphate rock powder is smaller,the corresponding disintegration time become longer.Under the same grinding time,the disintegration time of different proportions of raw materials roughly as follows: 1:15 group>1:30 group>1:0 group;The disintegration time of different particle size are as follows: 5~10mm group>3~5mm group>1~3mm;The disintegration time decreases when the amount of bentonite is bigger,and attapulgite content has no effect on disintegration time;When the content of bentonite,microcrystalline cellulose,sodium carboxymethyl starch all are 5%,the disintegration time are as follows: microcrystalline cellulose group>carboxymethyl starch sodium group>bentonite group,this three disintegrating agents have a significant difference.4、The order of the absorption rate of different disintegrant are as follows: bentonite> sodium carboxymethyl starch > microcrystalline cellulose,the saturated water quantity are as follows: sodium carboxymethyl starch>microcrystalline cellulose>bentonite,microcrystalline cellulose and bentonite has little difference,only 1.75%;The water absorption process of three kinds of disintegrant conforms to the water absorption kinetics equation,the water absorption time lags are as follows: sodium carboxymethyl starch>microcrystalline cellulose>bentonite.Compared with sodium carboxymethyl starch,bentonite and microcrystalline cellulose time lag reduced by 43.00%,12.33% respectively.In terms of water absorption rate,bentonite and carboxymethyl starch increased by 37.20% and 4.71% respectively compared with microcrystalline cellulose.In conclusion,the hydrophilicity of bentonite is the best,and the water absorption rate is the fastest.Therefore The disintegration effect of bentonite is the best.5、The results of the drying test show that this section focuses on the decreasing drying stage due to the relatively shorter or non-existent time of acceleration and constant stage.Among the four selected factors,the effect of drying temperature on the moisture ratio and drying speed is the most significant,followed by the addition of water,the effect of the fineness of ground phosphate rock and the amount of attapulgite are little.In general,the drying rate decreases gradually,and the influence of the factors becomes smaller in the later stage.The influence of drying temperature on the moisture ratio can be simulated by Wang experience model,the results show that fitting effect is good.