钾长石-磷矿-硝酸体系球磨反应过程研究

研究了钾长石-磷矿-硝酸体系球磨反应效果,得出较为适宜的工艺参数是:硝酸质量分数为45%,每克磷矿硝酸用量为2 m L,球磨时间为8 h,m(球磨子)/m(物料)为30,球磨机转速为600 r/min。原料配比对钾的溶出率影响最大,在磷矿与钾长石质量比为2时,钾的溶出率可以达到90%以上。     

钾长石-磷矿-盐酸反应体系实验研究

建立钾长石-磷矿-盐酸反应体系,综合利用钾长石和磷矿,全面考察影响该体系磷、钾溶出率的各种因素。用过0．074mm标;住筛的钾长石和磷矿为原料,最适宜反应条件为：磷矿石与钾长石质量比为1,盐酸（1＋1）加入量为5．6mL／g钾长石,反应温度为200℃,反应时间在70min以上,此时钾和磷的溶出率都能达到90％以上。     

钾长石与磷矿磷酸反应机理研究

分析了钾长石、磷矿、磷酸不同组合反应体系的钾、磷溶出率,并用XRD和FTIR对反应物和产物进行了物相分析。实验结果表明:磷酸不能分解钾长石,但加入磷矿以后,钾长石中钾可以被大量提出;反应分二步,首先是磷酸分解磷矿生成可溶于水的Ca(H2PO4)2和HF,然后HF能分解钾长石,但钾长石中钾的提取主要是Ca(H2PO4)2电离的Ca2 与钾长石中K 发生离子交换反应的结果。实验结果还表明,体系中的氟也会以K2SiF6的形式固定钾而降低钾的溶出率。     

钾长石与磷矿共酸浸提钾过程实验研究

参考重钙生产工艺，研究了磷酸用量、磷酸质量分数、磷酸温度、反应时间和矿石质量比对钾长石中钾溶出率和磷矿中磷的溶出率的影响，得出了适宜工艺条件．并对磷矿中氟离子的去向进行了探讨。     

湖北某磷矿反浮选钾长石试验研究

针对湖北某低品位难选硅钙(镁)质磷矿,主要脉石矿物为钾长石,原矿P2O5品位19.84％,SiO2品位27.78％.在磨矿细度-0.074 mm占比80.16％,预先脱除白云石及细泥的情况下,用醚胺类捕收剂T-609反浮选钾长石,可获得精矿P2O5品位33.65％,回收率达72.83％的良好指标,实现了磷灰石和钾长石的有效分离.捕收剂T-609与钾长石主要以物理吸附为主,T-609和消泡剂TOP的搭配使用,可有效改善阳离子捕收剂反浮选钾长石泡沫性能.     

钾长石-萤石-硫酸-氟硅酸体系提钾工艺研究

实验研究了钾长石-萤石-硫酸-氟硅酸体系提钾工艺过程.结果表明,该体系下提钾优化工艺条件为:m(萤石):m(钾长石)=0.35:1,质量分数为60%的硫酸、10%的氟硅酸用量分别按,m(H2SO4):m(钾长石)=1.35:1、m(H2SiF6):m(钾长石)=0.162:1,反应温度为120℃、反应时间为3.5 h,...     

钾长石-磷矿-硝酸脲体系分解钾长石的探讨

详细研究了钾长石与磷矿、硝酸脲反应的提钾新工艺, 验证了钾长石-磷矿-硝酸脲体系分解钾长石提取有效钾的可行性。通过正交实验得到各因素对钾溶出率影响大小依次为：反应温度>硝酸用量>反应时间>尿素与硝酸物质的量比。得到适宜的工艺条件：尿素和硝酸物质的量比为1:1;5.5 mol/L的硝酸用量为4 mL;反应温度为120 ℃;反应时间为2 h。在此条件下有效钾的溶出率可达96.23%,水溶性钾溶出率可达29.65%。通过单因素寻优实验得出钾长石与磷矿、硝酸脲反应提取有效钾的适宜工艺条件：反应温度为105～115 ℃,硝酸用量约为4.7 mL,反应时间约为2 h。     

钾长石作为助熔剂熔融还原磷矿的可行性研究

研究了钾长石对磷矿熔融还原反应的工艺及动力学,考察了反应温度、反应时间、酸度值及焦炭过剩系数对磷还原率的影响.结果表明磷的还原率均随反应温度、反应时间、酸度值、焦炭过剩系数的增大而增大,最佳工艺条件为反应温度1300℃,反应时间40min,酸度值0.85,焦炭过剩系数1.05,磷的还原率达到99.61％.针对不同温度下还原率与时间的变化进行拟合,得到不同温度下的反应速率,再由反应速率对浓度的对数值作图,得到反应级数.结果表明磷矿熔融还原的反应级数不是定值而是随反应温度变化的.利用Arrhenius公式计算得到反应的活化能Ea为100.71kJ/mol.     

我国钾长石利用工艺评述

介绍采用三种不同工艺利用钾长石为主要原料, 生产不同氧化钾含量的钾肥。     

磷石膏、钾长石和碳酸钙体系反应历程研究

利用HSC Chemistry 5热力学计算软件对磷石膏、钾长石和碳酸钙体系进行了热力学计算,并对焙烧产物进行了XRD分析测试。计算和测试结果均表明,当n(CaSO4)∶n(KAlSi3O8)∶n(CaCO3)=1∶2∶6,焙烧产物为CaSiO3和Ca2Al2SiO7时,反应体系的起始反应温度最低,约为320℃,反应最容易进行。     

高能球磨法制备铈锆铝复合氧化物的工艺

采用高能球磨法制备铈锆铝复合氧化物,运用XRD、SEM等方法研究CeO₂-ZrO₂-Al₂O₃复合催化材料分别在不同球磨时间、不同成分含量、不同焙烧温度和不同球磨工艺路线下的组织结构和稳定性能。结果表明：①随球磨时间的延长,各组元晶粒细化效果越来越明显,球磨30h,CeO₂晶粒约20nm,颗粒约200nm,但复合粉末一直未发生机械合金化。②经30h球磨的复合粉体,在1000℃以下具有良好的稳定性能,高温下有少量的ZrO₂溶入CeO₂中形成固溶体,CeO₂-ZrO₂和Al₂O₃之间表现出一定的协同稳定效应,而在1000℃以上相结构变化明显。③质量分数为18%的CeO₂和6%的ZrO₂的复合粉体颗粒比较细小,分布比较均匀,对γ-Al₂O₃的稳定化效果比较理想。④采用先将CeO₂和ZrO₂球磨30h,再添加Al₂O₃并继续球磨30h的高能球磨工艺,可制备出含大量CeO₂-ZrO₂固溶体的复合粉体,CeO₂-ZrO₂与γ-Al₂O₃相互改性作用更加理想。     

Simultaneous wet ball milling and mild acid hydrolysis of rice hull

BACKGROUND: Rice hull, an abundant residue but a big issue for the rice processing industry, has the potential to serve as a feedstock for production of ethanol because of its lignocellulosic composition. Simultaneous wet ball milling and mild acid hydrolysis of rice hull was studied in this work. RESULTS: Ball milling with 150 small stainless steel beads and rotation speed of 600 rpm in citrate solvent of pH 4 was the optimal condition for hydrolysis, and the yield of sugar increased with increased milling time. Corresponding structure transformations before and after milling analyzed by X‐ray diffraction (XRD), environmental scanning electron microscopy (ESEM) and transmission fourier transform infrared spectroscopy (FT‐IR) clearly indicate that this hydrolysis could be attributed to the crystalline and chemical structure changes of cellulose in rice hull during ball milling in mild acid solvent. CONCLUSION: This combined treatment of ball milling and citrate solvent greatly changed the crystalline and chemical structure and continuously generated sites accessible to citrate solvent, thus enabling hydrolysis of the rice hull. Copyright © 2009 Society of Chemical Industry     

Computer-aided reaction system synthesis based on structured process energy-exergy-flow diagram

A computerized thermodynamics-oriented procedure for reaction system synthesis is proposed. First, hierarchy structure of chemical reactions is discussed and the reaction system is categorized into three types; (1) combination with a heat source or sink, (2) combination with a reaction donor, and (3) decomposition of target reaction into subtargets. Then, the algorithm to find subtarget reactions and/or donor reactions is presented.     

机械力化学方法活化矿渣研究

根据机械力化学原理,采用高能球磨技术对3种矿渣进行活化,分别研究了3种矿渣的粒度、密度和净浆小试体抗压强度的变化规律,并初步探讨了机械力化学活化矿渣的机理。结果表明,机械力化学高能球磨能够使矿渣粉体迅速细化,明显提高矿渣的水化活性和水化强度;矿渣本身的抗压强度很低,掺入Ca(OH)2后强度显著提高,最高可达65 37MPa;高能球磨2～4h为最佳处理时间。     

Study of the process of stirred ball milling of poorly water soluble organic products using factorial design

The objective of this work was to investigate the mechanism of very fine grinding in a wet ball mill as a function of process parameters, i.e. rotation speed of the mill and grinding medium bead size. The ball mill used was a Dynomill and the grinding medium consisted of zirconium oxide beads. The product is a poorly water-soluble organic compound. Laser diffraction was used to analyze the particle size distribution.During grinding the average particle diameter of the product was reduced to a minimum size, which was constant within the range of tested operating conditions.The grinding parameters were studied to control the grinding process with respect to the required grinding time for reaching the minimum particle size and wear of the set-up.The grinding time was strongly dependent on the grinding medium bead size and on the rotation speed. The grinding process became faster when the rotation speed increased and the grinding medium bead size decreased. The wear of the set-up, and therefore the contamination of the final product with heavy metals, strongly increased with the rotation speed. A similar trend was observed with an increase of grinding medium bead size. The degradation rate of the product was not significant in the range of grinding parameters studied.     

Synthesis, sintering and characterization of PNZST ceramics from high-energy ball milling process

Pb_0.99Nb_0.02[(Zr_0.60Sn_0.40)_0.94Ti_0.06]_0.98O₃ powders were synthesized from oxide mixtures of Pb₃O₄, Nb₂O_5, ZrO₂, SnO_2, and TiO₂ using a Fritsch P4™ vario-planetary ball milling system. The perovskite structure of PNZST powder can be obtained well after 14 h milling and crystallite size of the powders greatly reduced to 20–30 nm. The resultant powders have better sinterability characteristics to obtain dense ceramic bodies at low temperature. The dielectric constant of samples shows a maximum at 1150 °C and the PE_MC to PE_SC transformation temperature shifts to higher temperature with an increase in grain size. The field-induced strain reaches maximum longitudinal strain of 0.32% and the P–E hysteresis loop shows much higher squareness at 1150 and 1200 °C. The measured dielectric and antiferroelectric properties of the PNZST ceramics were found to be comparable to those from other processing techniques.