本文關(guān)鍵詞： 硅灰石 硅肥 助熔劑 動(dòng)力學(xué) 機(jī)理研究 盆栽試驗(yàn)　出處：《華南理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：硅是農(nóng)作物生長(zhǎng)不可缺少的第四大營(yíng)養(yǎng)元素,是組成巖石礦物的一種基本元素,廣泛存在于自然界中,但是此種硅元素幾乎都以結(jié)晶態(tài)和無(wú)定形態(tài)存在,不能被植物直接吸收。我國(guó)土壤中缺少硅元素的耕地面積約占總面積的50%以上,而目前我國(guó)硅肥的年生產(chǎn)能力不高,遠(yuǎn)不能解決我國(guó)耕地嚴(yán)重缺少硅的問(wèn)題。因此,利用難溶性含硅礦物生產(chǎn)硅肥,滿足國(guó)內(nèi)市場(chǎng)對(duì)硅肥的需求是當(dāng)務(wù)之急。本研究以硅灰石和白云石為主要原料,配伍以為助熔劑制備硅肥,并對(duì)工藝條件如物料配比、焙燒溫度和時(shí)間等因素進(jìn)行了初步探討。實(shí)驗(yàn)利用優(yōu)化后的硅鉬藍(lán)分光光度法測(cè)定硅肥中有效二氧化硅的含量,并采用X射線粉末衍射(XRD)、掃描電子顯微鏡(SEM)、紅外吸收光譜(FTIR)、電子探針(EPMA)、同步熱分析(TG-DSC)等方法詳細(xì)分析了原材料和焙燒產(chǎn)物的物化性質(zhì)。此外,本文對(duì)硅灰石與白云石的反應(yīng)機(jī)理進(jìn)行了探討并利用動(dòng)力學(xué)的方法研究了助熔劑對(duì)硅灰石-白云石反應(yīng)體系的影響。結(jié)果表明:(1)優(yōu)化后的硅鉬藍(lán)分光光度法操作更為簡(jiǎn)便快捷、準(zhǔn)確。溶解樣品時(shí)稱樣量宜低于0.2 g,振蕩頻率宜采用170-190 r/min,用2%的檸檬酸溶液作為浸取劑提取硅肥中的有效硅成分更具有現(xiàn)實(shí)意義。優(yōu)化后的硅鉬藍(lán)分光光度法精密度和準(zhǔn)確度良好,多次重復(fù)測(cè)定的極差小于0.6%,標(biāo)準(zhǔn)偏差小于0.2%,加標(biāo)回收率為98.5%-101.3%。(2)最佳物料配比為n(硅灰石):n(白云石):n(助熔劑)=1:0.3:0.4;最適宜的焙燒條件為1000°C、1 h,在此條件下,有效二氧化硅的含量為21.6%。焙燒后的硅灰石由針狀和短柱狀轉(zhuǎn)變?yōu)槎讨鶢?呈相互交生狀,內(nèi)表面積增大,硅灰石表面被活化。焙燒產(chǎn)物的主要物相為CaSiO3(CS)、Ca2SiO4(C2S)、Mg2SiO4、Ca3Mg(SiO4)2(C3MS2)和Ca2MgSi2O7(C2MS2),它們?cè)? g/L的檸檬酸溶液中,其有效二氧化硅、鈣和鎂等成分幾乎全部溶出,即以它們?yōu)橹饕煞值墓璺始词乖诘蜐舛鹊挠袡C(jī)酸(與土壤環(huán)境相似)條件下也能釋放肥效,技術(shù)上可行,具有實(shí)際指導(dǎo)意義。(3)助熔劑對(duì)硅灰石-白云石反應(yīng)體系有重要的作用,提高了體系的反應(yīng)速率。助熔劑的添加使得白云石的分解溫度和硅灰石與白云石發(fā)生反應(yīng)的初始溫度分別降低了22°C和21°C。從動(dòng)力學(xué)角度,硅灰石-白云石體系在助熔劑作用下熱分解的過(guò)程符合金斯特林格方程,助熔劑將硅灰石-白云石體系的表現(xiàn)活化能從106.89 kJ/mol降低到90.64 kJ/mol。(4)硅肥對(duì)小白菜的株高、根系生長(zhǎng)以及生物量影響較大,施入硅肥量1‰的盆栽比空白組在株高、根重和生物量上分別增加了48.8%、49.6%、102.4%。施入適量的硅肥能夠提高小白菜的發(fā)芽率,但是過(guò)量會(huì)導(dǎo)致燒苗現(xiàn)象,降低發(fā)芽率。從實(shí)際土壤情況和經(jīng)濟(jì)效益方面考慮,可將100 kg/畝的施入量作為農(nóng)田施肥指標(biāo)。
[Abstract]:Silicon is an indispensable nutrient element in the growth of crops and a basic element of rock minerals, which widely exists in nature, but it almost exists in crystalline and amorphous forms. It can not be directly absorbed by plants. The area of cultivated land lacking silicon element in our country accounts for more than 50% of the total area, but the annual production capacity of silicon fertilizer in our country is not high at present. Therefore, it is urgent to use insoluble silicon-containing minerals to produce silicon fertilizer and to meet the domestic market demand for silicon fertilizer. Wollastonite and dolomite are the main raw materials in this study. The mixture is used as flux to prepare silicon fertilizer, and the technological conditions such as the ratio of materials are given. The factors such as calcination temperature and time were preliminarily discussed. The content of effective silica in silicon fertilizer was determined by optimized silicomolybdate blue spectrophotometry, and X-ray powder diffraction (XRD) was used. Scanning electron microscope (SEM), infrared absorption spectroscopy (FTIR), electron probe (EPMA). The physical and chemical properties of raw materials and roasted products were analyzed in detail by simultaneous thermal analysis (TG-DSC) and other methods. The reaction mechanism of wollastonite and dolomite was discussed and the effect of flux on wollastonite dolomite reaction system was studied by kinetic method. The optimized silicon molybdenum blue spectrophotometry is more convenient and rapid. The sample size should be less than 0.2 g and the oscillation frequency should be 170-190 r / min. The extraction of effective silicon from silicon fertilizer with 2% citric acid solution is of practical significance. The precision and accuracy of the optimized silicon molybdenum blue spectrophotometry are good. The range difference of repeated determination is less than 0.6 and the standard deviation is less than 0.2%. The optimum material ratio is n (wollastonite: n) (dolomite: n) (flux 1: 0. 3: 0.4; flux: 1: 0. 3: 0. 4) the standard recovery rate is 98.5- 101.3%, and the optimum material ratio is n (wollastonite: n). The optimum calcination condition is 1000 擄C ~ (-1) h, under which the effective silica content is 21.6. the calcined wollastonite changes from needle-shaped and short column-shaped to short column-shaped, and it is intersected. The surface of wollastonite is activated with the increase of internal surface area. The main phase of calcined product is CaSiO3C2SiO4C2SiO4 and Mg2SiO4. Ca3MgSiO2C3MS2) and Ca2MgSi2O7C2MS2N, which are effective silica in 5 g / L citric acid solution. Almost all the components such as calcium and magnesium are dissolved, that is, silicon fertilizer with them as the main component can release fertilizer efficiency even under the condition of low concentration of organic acid (similar to soil environment), which is technically feasible. The flux has important effect on wollastone-dolomite reaction system. With the addition of flux, the decomposition temperature of dolomite and the initial temperature of reaction between wollastonite and dolomite were reduced by 22 擄C and 21 擄C. The process of thermal decomposition of wollastone-dolomite system under flux action accords with the Kingstringer equation. Flux reduced the apparent activation energy of wollastone-dolomite system from 106.89 kJ/mol to 90.64 kJ / mol 路m.4) the plant height of pakchoi treated with silicon fertilizer. The plant height, root weight and biomass were increased by 48.8% and 49.6% in potted plants with 1 鈥，

本文編號(hào)：1490153