胶磷矿酸解反应活性的研究

研究用硫、磷混酸分解贵州福泉和开阳磷矿、四川清平和金河磷矿的反应速度，并比较这几种磷矿被酸分解的活性。研究结果表明，福泉磷矿被酸分解的活性最强，清平磷矿活性最差。此外，还探讨了磷矿的显微结构、比表面积及组成等对其酸解反应活性的影响。     

中低品位磷矿浮选尾矿制备磷镁肥的实验研究

研究开发一种以中低品位磷矿浮选尾矿为原料,采用硫磷混酸直接分解浮选尾矿制备磷镁肥的方法。阐述了浮选尾矿的矿物特性,硫磷混酸分解浮选尾矿制备磷镁肥的基本原理、工艺条件、产品质量,论证了中低品位磷矿浮选尾矿制备磷镁肥的可行性。     

硫磷混酸分解马边磷矿的反应过程动力学特性

采用四川马边磷矿,研究硫磷混酸分解磷矿的反应温度、磷矿粒度与分解率的关系。指出过程属扩散和化学反应的联合控制,并得到了过程传质系数及反应活化能（Ｅａ＝４２．８７ｋＪ／ｍｏｌ）。经归纳整理,提出混酸分解四川马边磷矿生产磷酸的动力学模型Ｋ＝１．０７４８×１０５ｅｘｐ（ｌ－４２．８７）／ＲＴ）,并对模型进行了检验。     

硫磷混酸分解清平磷矿第二阶段酸解特性研究

采用四川清平磷矿，研究了硫磷混酸分解磷矿第２阶段的酸解反应特性。实验结果表明扩散对过程影响严重，在此基础上提出了强化第２阶段反应过程的措施。     

硫磷混酸分解清平磷矿第二阶段解特性研究

采用四川清平磷矿，研究了硫磷混酸分解磷矿第２阶段的酸解反应特性，实验结果表明扩散对过程影响严重，在此基础上提出了强化第２阶段反应过程的措施。     

磷矿浮选尾矿在硫磷混酸中的分解动力学研究

对硫磷混酸分解磷矿浮选尾矿的动力学进行了研究,结果表明,随着反应温度和P2O5浓度的提高,尾矿中MgO和P2O5的浸出率提高,在相同条件下,MgO浸出率高于P2O5浸出率,且由于磷酸的加入,生成了溶解度较大的Ca(H2PO4)2,降低了硫酸钙固体膜层的影响,有效改善了反应物和生成物通过固体膜层的扩散过程.硫磷混酸分解磷矿浮选尾矿的动力学,可用形成致密固体反应物膜的收缩未反应核模型来描述,动力学模型与实验结果拟合直线的相关系数均在0.97以上.通过.Arrhenius方程计算,MgO的表观活化能为9.95 kJ/mol,P2O5的为12.84 kJ/mol,说明硫磷混酸分解磷矿浮选尾矿容易进行,也说明酸解过程属于扩散控制过程.     

鹤峰磷矿在硫、磷混酸中的溶解动力学

对鹤峰磷矿在硫、磷混酸中的溶解动力学进行了研究,考查了硫酸质量分散及反应温度对酸解过程的影响;选用考虑了自阻化因素的德罗兹多夫方程In100/(100-Kp)-βKKp%=kt描述酸解过程的动力学.研究结果表明:鹤峰磷矿在硫、磷混酸中的反应速率常数随温度升高而增加,随硫酸质量分效的增加而减小.该反应属于扩散控制,平均反应活化能约为32.7kJ/mol.     

金河磷矿在硫、磷混酸中的溶解动力学

参考二水物湿法磷酸的生产工艺条件,进行了金河磷矿在硫、磷混酸中的酸解动力学研究．考察了矿粉粒度、硫酸浓度及反应温度对酸解过程的影响;选用考虑了自阻化因素的德罗兹多夫方程描述酸解过程的动力学;利用修改后的Gioia酸解模型求得了磷矿酸解过程的有效扩散系数．     

关于湿法三聚磷酸钠生产过程中脱氟必要性的探讨

生产五钠的湿法工艺是众所周知的。目前国内的工艺过程为:磷矿石粉碎成一定的颗粒度以后,在萃取槽中用硫、磷混酸分解(此过程俗称磷矿的萃取),过滤分离生成的硫酸钙水合晶体,得到湿法磷酸。湿法磷酸静置净化后,经用碳酸钡脱硫、用纯碱中和至一定的中和度,分离去所形成的水不溶性沉淀(俗称中和碱渣),将滤液磷酸钠盐溶液浓缩,再喷雾干燥、聚合即得产品五钠。在用硫-磷混酸分解磷矿石时,原料中的许多杂质进入磷酸溶液中,使湿法磷酸中含有大量的阴离子和阳离子杂质。这种低质     

金河磷矿中磷、铁、铝和镁的酸解动力学研究

研究用大量磷酸分解磷矿的反应过程,并对金河磷矿中的磷、铁、铝和镁的酸解动力学过程进行了分析.研究表明,随着反应温度、磷酸浓度、颗粒细度的增加,磷矿分解速率均有增加,同时揭示了金河磷矿中铁、铝、镁杂质的分解规律.因铁杂质的赋存形态为FeS2,其最大分解率低于20%;而铝杂质分解率较高,其最大分解低于45%,并且它们的分解过程在一定的酸浓度范围内呈负温度效应.     

Comparison between acidulation by sulfuric acid and by phosphoric acid for Saudi phosphate rock

A detailed investigation of two phosphate rock acidulation modes has been carried out in batch acidulators. The classical dihydrate process rate is affected by the coating of the rock particle by gypsum. The clean phosphoric acid process using phosphoric acid as an acidulation agent does not suffer from this inhibitory coating effect, however it is affected by the increasing viscosity of the solution during acidulation. Under practical conditions the rate of acidulation using phosphoric acid is much higher than that of the dihydrate process using sulfuric acid as an acidulation agent.     

脲硫酸分解磷矿宏观动力学研究

以保康矿为基础,对脲硫酸分解磷矿的宏观反应动力学进行了研究,该反应过程中阻化作用对反应速率影响很大,阻化系数β随反应温度升高、矿粉粒度减小而增大,随酸解剂摩尔比而变化。在磷矿粒度为0.110—0.174mm,反应温度为339—359 K和酸解剂摩尔比为n(尿素)∶n(硫酸)=2.0—3.6∶1的条件下,实验得到包含阻化系数的脲硫酸分解磷矿过程的宏观动力学方程,方差分析表明模型可靠,为工艺条件的优化和反应器的设计提供了理论依据。     

Single superphosphate-reactive phosphate rock mixtures. 1. Factors affecting chemical composition

The effect of additon of reactive phosphate rock (RPR — North Carolina) on the degree of acidulation of unreactive phosphate rocks (PRs — Nauru and Christmas Island A) during the manufacture of single superphosphate (SSP) was examined using³²P in isotopic dilution studies. Acidulation of unreactive PR during SSP manufacture continued through denning, granulation and drying. Even after 3 hours drying, between 20 and 30% of the total P remained as free phosphoric acid in the reaction mixture. The addition of North Carolina phosphate rock (NCPR) to ex-den SSP reaction mixture (3:7 NCPR:SSP reaction mixture) preferentially consumed the free phosphoric acid remaining in the reaction mixture. This resulted in reduced acidulation of the unreactive PR in the reaction mixture and partial acidulation (10–23%) of the RPR. Hence the SSP-RPR mixture contains more residual, unreactive PR than is present in SSP.The extent of partial acidulation of the RPR when mixed with SSP was determined by the nature of free acid remaining in the SSP reaction mixture, which in turn is affected by the type of unreactive PR used for SSP manufacture. The free acid in the Christmas Island A reaction mixture contained approximately 8 and 12 times as much Fe and Al respectively as that in the Nauru reaction mixture, and was only half as effective at converting the P in RPR to soluble P. Unless made with extended denning times and carefully chosen PR, SSP-RPR mixtures can contain (a) undesirable amounts of unreactive PR residues, and (b) low quality partially acidulated RPR, both of which have low agronomic value.     

Factors affecting the solubility of phosphate rock residues in 2% citric acid and 2% formic acid

The 2% citric and formic acid solubilities of phosphate rock residues extracted from partially acidulated materials (20 and 35% acidulation) manufactured from two phosphate rocks (both ground and unground) in the presence of monocalcium phosphate, monosodium phosphate, calcium chloride, calcium sulphate, calcium carbonate, sodium carbonate and aluminium and iron sulphates have been examined. Such figures have been compared with previous results obtained for the equivalent unprocessed phosphate rocks. In general the effects of additives on the solubility of the phosphate rock residues were similar to those found for unprocessed phosphate rocks. However, the solubility figures were considerably lower for the 20% acidulated residues, while 2% formic acid solubilities for the 35% acidulated residues were also reduced. This would indicate that some deactivation of the phosphate rock had taken place during acidulation, the degree of which was dependent on the acidulation level and could be more readily observed in changes in 2% formic acid solubility than in 2% citric acid figures.     

An evaluation of the agronomic potential of partially acidulated rock phosphates in calcareous soil

The agronomic potential of four partially acidulated rock phosphates (PARP) made from a moderate reactive phosphate rock at 30 or 60 percent acidulation either by sulfuric acid alone or by combination of sulfuric and phosphoric acids was compared with that of monocalcium phosphate (MCP) and ground rock phosphate (RP) on a calcareous soil (Typic Hapluquent, pH 8.5) in greenhouse. Dry weight and P accumulation of successive cuttings of ryegrass shoots were used to evaluate the relative agronomic potential of these fertilizers. Results indicated that PARPs of higher water-soluble P content had similar immediate effectiveness as MCP at two earlier cuttings, however, they produced significantly less total dry matter than MCP did in overall six successive cuttings. PARPs were constantly inferior to MCP in terms of P uptake by plant in all the six cuttings. When compared to RP, on the other hand, PARPs had markedly higher relative effectiveness. RP itself affected neither the dry matter production nor the P uptake by plant as compared to control treatment.Fractionation of residual inorganic P in the soil samples at two time intervals during plant growth indicated that MCP-P mainly transformed to dicalcium phosphate and octacalcium phosphate, and to a less extent to Fe and Al associated P. These forms of P had significant correlation with P accumulation by plant. Raw RP did not subject to transformation after applied to the soil regardless the duration of culture time. No obvious dissolution of unreacted RP in PARP materials was detected. Plant dry matter production and P uptake were mainly correlated with water-soluble P added with the fertilizers. It is suggested from the experiment that although partial acidulation could substantially improved the effectiveness of rock phosphate and the immediate effect of the fertilizer was competitive with MCP, application of PARP to calcareous soils is only of short-term benefits; in a long run this fertilizer is not considered as a desirable source of P in calcareous soils since the unacidulated part in the fertilizer was unable to be solubilized in the alkaline conditions.     

Processing aspects of production of partially acidulated phosphate rock fertilisers using phosphoric acid

Several factors which could affect the rate of reaction between phosphate rock and phosphoric acid in the production of partially acidulated phosphate rock fertilisers (20 to 50% of stoichiometric) were examined. Fineness of the phosphate rock had predictably the largest effect, with rates increasing markedly with increasing fineness. Quality of the phosphoric acid also had a noticeable effect, especially in the acidulation of unground phosphate rock, where use of poorer quality acids caused reductions in reaction rate and consequent detrimental effects on the physical condition of products. Acid concentration was an important factor in determining the physical condition of the product but had only a small influence on reaction rate.None of the above factors had a major influence on the total or percentages of soluble phosphorus in matured products. Slightly higher phosphorus percentages at the same level of acidulation were obtained with the finer phosphate rock and better quality phosphoric acids, but overall any variations in the phosphorus analyses attained at any specific acidulation level were considered of minor importance in comparison to processing and agronomic limitations of partially acidulated phosphate rock fertilisers in the New Zealand agricultural situation.