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研究以二水磷酸氢钙为原料,采用煅烧法生产无水磷酸氢钙。通过生成的水蒸汽压,煅烧时间为3h,煅烧温度140℃,产品质量可达孟山都公司食品用无水磷酸氢钙标准。 相似文献
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石灰乳是磷酸氢钙生产所需的原料之一,其制备工艺对磷酸氢钙产品的品质、生石灰消耗量和石灰渣排放量都有较大影响。通过改进生石灰的储存方式、消化工艺以及石灰浆的净化方式,实施后使每吨磷酸氢钙产品的生石灰消耗量降低约33%、石灰渣排放量减少约67%,并提升了石灰乳以及磷酸氢钙产品的品质,取得了良好的应用效果。 相似文献
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梁祖义 《中国石油和化工标准与质量》1998,(4)
HG2636—94《饲料级磷酸氢钙》是在1987年版标准基础上修订的.新标准不仅技术指标有所变动,而且第一章的叙述也有改动,例如:老标准这样写道:本标准适用于磷酸与含钙原料反应生成磷酸氢钙,在饲料加工中作钙、磷的补充剂。新标准则改为:本标准适用于饲料级磷酸氢钙,该产品在饲料加工中作钙、磷的补充剂。两者区别在于:老标准指出了标准的适用范围在于用磷酸为原料生产的磷酸氢钙,而新标准则没有指明用何种原料。看起来似乎新标准比老标准在“最大自由度”方面,更符合标准编写的三大基本原则,是产品标准向商品标准过渡的进步之举… 相似文献
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《无机盐工业》2017,(9)
以湿法磷酸制备的饲料级磷酸氢钙为原料,开发工业级磷酸二氢钾的生产工艺。通过加入适量的磷酸提高磷酸氢钙的分解率,研究了磷酸氢钙与磷酸的预分解反应条件及其与硫酸氢钾复分解反应的条件。优化条件:饲料级磷酸氢钙悬浮液的液固比为4 mL/g,磷酸、磷酸氢钙、硫酸氢钾物质的量比为0.3∶1∶1,反应温度为60℃,硫酸氢钾在反应开始的1 h内均匀加入,反应时间为2 h。在此条件下,复分解反应中饲料级磷酸氢钙中的磷收率达到94.5%,硫酸氢钾中的钾收率达到99.9%。研究提出,以磷酸预分解磷酸氢钙以及结晶母液循环的磷酸二氢钾制备工艺,解决了磷和钾收率低以及生产成本高的问题,同时无废液排放。 相似文献
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以TFT-LCD磷酸蚀刻废液为原料,重质CaCO_3和工业Ca(OH)_2为中和剂,通过二段结晶法制备饲料级磷酸氢钙,考察了结晶温度、搅拌速度、进料速度、一段/二段终点pH、CaCO_3料浆浓度、Ca(OH)_2料浆浓度、一段/二段终点停留时间等因素对磷酸氢钙产品品质的影响。结果表明,制备饲料级磷酸氢钙的优化条件为:结晶温度40℃、搅拌速度200 r/min、进料速度10 mL/min、CaCO_3料浆浓度200 g/L、Ca(OH)_2料浆浓度100 g/L、一段终点pH=3.5、一段终点停留时间0 min、二段终点pH=5.5、二段终点停留时间60 min。在优化的结晶条件下,磷酸蚀刻废液制备得到的饲料级磷酸氢钙可满足《GB/T 22549-2008饲料级磷酸氢钙》中Ⅰ型产品的要求,并且其含水率可控制在30%以下。 相似文献
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Pectins are polysaccharides which are able to gel in the presence of calcium ions if their degree of esterification is lower than 40%. From a purified pectin, a de-esterification was carried out by alkali and by enzymes in order to obtain samples with a different charge density and esterification pattern (random or blockwise distribution of carboxylic acid sites). The pectin-calcium interactions were studied in a dilute solution of calcium pectinates by conductimetry. If the concentration of highly charged polymer is increased, a multichain association can occur: the same process is observed with dilute solutions (cp≤10-3 eq. 1?1) but in the presence of an excess of calcium ions. This first step of the gelation was followed by light scattering and by viscometry. The gelling system can be described by a power law including a critical ratio (equivalent concentration of calcium ions/pectin carboxylic sites) and quasi-critical exponents. The values of these critical parameters have been discussed as a function of charge density of the pectins, their esterification pattern, their concentration, and the nature of the divalent counterion. 相似文献
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钙盐-电凝聚法处理含氟工业废水 总被引:2,自引:2,他引:0
对钙盐-电凝聚法处理含氟工业废水的影响因素和效果进行了试验和分析。试验结果表明,钙盐-电凝聚法处理含氟工业废水的最佳反应条件为:n(Ca2+)/n(F-)为1~2,电流密度为1~5mA/cm2,电解时间t为10min,pH值为6~9,投加的钙盐以CaCl2最佳。现场试验钙盐-电凝聚法处理含氟工业废水比传统药剂混凝好,出水能够达到国家排放标准。 相似文献
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Sunjip Kim Jin-Young Park Yong-Woo Lee Jae-Jin Lee Jeong-Yun Choi Yun-Kyu Choi Philip Vella 《Desalination》2009,249(2):554-559
The Hyperkinetic Vortex Crystallization (HVC) process using hydrodynamic cavitation technology was investigated to remove high calcium levels from the effluent of the fluoride removal process used in a semiconductor manufacturing company. Due to low alkalinity in the effluent of this wastewater, addition of sodium carbonate was necessary. The relatively stable effluent calcium concentration of 8.0-52.8 mg/L was achieved although the influent calcium concentration severely fluctuated in the range of 173-371 mg/L. A calcium removal efficiency of 84.5-97.0% was determined with the HVC process. To confirm the cavitation effect, the calcium removal process was operated with and without the use of the VRTX cavitation system. The calcium removal efficiency increased from 63.5% to 91.7% when the VRTX unit was operating. The change of the calcite shape from plate to a spherical form by VRTX application was also observed. This can enhance calcium removal because of the larger specific surface area for adsorption of newly produced colloidal calcites. The conversion of the calcite shape to spherical would also prevent (limit) formation of calcite scale in the inner wall of pipes and reactors. 相似文献
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由铁矿烧结电除尘灰浸出液制备氯化钾及球形碳酸钙 总被引:1,自引:0,他引:1
采用物理化学表征方法研究了包钢烧结电除尘灰的基础性质,结果表明,该烧结电除尘灰的主要成分为Fe,K,Na,Ca的化合物,其中的钾盐可通过水浸分离回收. 浸出液中含有大量可溶性硫酸钙. 为了在浸出过程中抑制硫酸钙的溶解,考察了硫酸钙在KCl,NaCl,K2SO4及其混合盐中的溶解性能. 结果表明,由于KCl和NaCl的盐溶效应,硫酸钙的溶解性能得到提升. 应采用低液固比,提高浸出液中硫酸根离子的相对含量,利用硫酸根离子的同离子效应抑制烧结电除尘灰中硫酸钙的溶解. 以碳酸钠为沉淀剂,考察其对钙离子沉淀效果的影响. 结果表明,碳酸钠具有较好的硫酸钙沉淀效果. 在沉淀钙离子的同时,研究了沉淀剂的浓度、反应温度、搅拌强度对碳酸钙晶体形貌的影响,制备获得了分散良好,粒径小于10 mm的球形碳酸钙副产品,实现了资源综合利用. 最后设计了从烧结电除尘灰提取国标20406-2006一级氯化钾并联产球形碳酸钙副产品的工艺路线,该工艺具有工业应用潜力. 相似文献
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钛白粉生产过程中硫酸亚铁是其主要的副产品,硫酸亚铁的产生量大,回收利用率低成了制约钛白粉生产的"瓶颈"。文章目的通过采用投加一定量的氯化钙然后调节pH来回收铁的方法对钛白粉生产过程中的副产品硫酸亚铁进行综合利用的实验分析。通过研究发现:氯化钙与硫酸亚铁反应过程中在一定的搅拌强度反应一段时间后,氯化钙的最佳投加量为Ca2+与SO42-的摩尔比1.3;氢氧化钙的最佳投加量OH-与Fe2+物质的量之比2.4,能够将硫酸亚铁中的铁全部转化成氢氧化铁,其中氯化钙溶液在整个系统中循环利用。 相似文献
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Leaching kinetics of calcium vanadate by Na2CO3 solution was studied. Kinetic equation was established according to the variation of VO3-concentration with time during the leaching process. The influences of initial pH value and stirring speed on reaction rate constant were examined and the corresponding apparent activation energy was calculated. The results indicate that the leaching process is a 0.68 order reaction, and the reaction rate constant 8.64×10-6 mol/(L-s). It increases with the increase of pH value and stirring speed. And the dissolution rate of calcium vanadate also increases. The apparent activation energy is 38.98 kJ/mol, and temperature has great influence on the leaching rate of calcium vanadate. 相似文献
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简要介绍了阿托伐他汀钙的性质和药理作用,分析了阿托伐他汀钙的全合成路线,选择以(4R-cis)-6-[2-(2-(4-氟基苯)-5-(1-异丙基)-3-苯基-4-[(苯胺)羰基-1H-吡咯-1-基)乙基]-2,2-二甲基-1,3-二氧己环-4-乙酸叔丁酯(Ⅱ)为原料经酸解、中和得到阿托伐他汀钙(Ⅰ),并对其合成工艺进行了优化。合成过程中使用2 mol/L的盐酸,控制原料和盐酸的摩尔比在1∶2.2时,反应75 min得产物,产率高达91.29%;粗品选择二氯甲烷与正己烷为溶剂进行重结晶可以得到较好的无定形阿托伐他汀钙固体;产品经结构分析确认为阿托伐他汀钙。 相似文献