改善过磷酸钙物性 缩短熟化期的研究

针对目前过磷酸钙存在熟化期长、易结块的问题,介绍了所需添加的活化疏松剂筛选和应用情况。试验证明,加入合适的活化疏松剂后,鲜肥转化率可提高３％￣１５％,生产的过磷酸钙镁肥堆积重压３５ｄ后仍不结块。     

活化疏松剂用于过磷酸钙生产的性能研究

介绍了在过磷酸钙中添加活化疏松剂的试验情况及运用效果。试验结果表明 :添加活化疏松剂后鲜肥转化率提高 4.0 % ,产品物性得到改善 ,结块倾向明显降低。     

加入活化疏松剂改善过磷酸钙物化性质 缩短熟化期

针对过磷酸钙肥料存在的易结块,熟化期长的问题开展了对过磷酸钙生产工艺进行优化的研究。该文公对添加活化疏松剂筛选试验和应用情况作一介绍。试验结果表明,根据不同矿种和条件,加入合适的活松剂后,鲜肥转化率较对比样,可提高３％－１５％,生产出的疏松过磷酸钙鲜肥堆积重压３５天后仍不结块。     

一种液体活化疏松剂在过磷酸钙生产中的应用

介绍一种由表面活性剂、分散剂和水加工而成的过磷酸钙液体活化疏松剂.生产过磷酸钙时1t产品加入液体活化疏松剂100～ 200 g,其鲜肥中w(P2O5有效)提高0.5～1.0百分点、w(H2O)降低1～2百分点,P2O5转化率提高3～6百分点,减少熟化翻堆次数,熟化时间缩短4～10d.     

活化疏松剂在过磷酸钙生产中的应用

为了解决过磷酸钙产品结块问题 ,采用郑州工业大学开发的过磷酸钙活化疏松剂。介绍活化疏松剂添加装置 ,添加量 (0 .9～ 1.1kg/ t肥 ) ,取得的效果。熟化期缩短至 4天内 ,转化率提高 4%以上 ,产品疏松     

用钛白废酸生产不结块过磷酸钙的研究

针对硫酸法钛白粉生产中废酸排放量大的问题,试验研究对废酸中的铁和钛进行回收并用废硫酸生产过磷酸钙的可能性.在过磷酸钙生产中添加活化疏松剂,可以使过磷酸钙产品疏松、不结块,物性良好,而且减轻了钛白粉厂的环境污染问题.     

过磷酸钙活化疏松剂的应用研究

介绍了在过磷酸钙生产中添加活化疏松剂的试验情况，活化疏松剂由表面活性剂和无机助剂组成。工业化试验结果表明，加入复配型活化疏松剂可使鲜肥转化率提高3％，产品物性明显改善，显著减少了产品结块。     

活化疏松剂在过磷酸钙生产中的应用试验

介绍活化疏松剂在过磷酸钙生产中的应用试验情况 ,基本解决了过磷酸钙结块问题 ,成品转化率提高3个百分点以上 ,鲜肥熟化期缩短至 6天以下     

中低品位磷矿生产不结块过磷酸钙的研究

针对我国磷矿总储量的90％为中低品位矿的现实,通过大量的工业试验研究,提出了利用中低品位磷矿生产不结块过磷酸钙的方法,试验证明：利用这种方法不仅可获得疏松、不结块的SSP产品,同时可节酸降耗,将熟化期缩短3－5天。     

E-35表面活化疏松剂在重过磷酸钙生产中的应用

探讨疏松剂在淤酸生产重过磷酸钙中的应用,主要是为了提高磷酸的活性,加快熟化速度,缩短熟化期.     

过磷酸钙颗粒的溶解动力学研究

过磷酸钙颗粒溶解机制及养分释放过程直接影响磷素利用率。通过研究20、25、30、35、40℃下过磷酸钙颗粒的溶解过程,明确过磷酸钙颗粒溶解过程符合缩芯模型,控制步骤先后为内扩散控制、界面和外扩散联合控制两个阶段,模型方程均达到线性显著水平(P0.05),且扩散控制步骤的转换渐进完成。研究结果对促进过磷酸钙的应用和提高肥料利用率研究具有科学意义。     

Effectiveness of rock phosphate, coastal superphosphate and single superphosphate for pasture on deep sandy soils

The effectiveness of coastal superphosphate and two rock phosphate fertilizers was compared with the effectiveness of single superphosphate for pasture production on deep, humic, sandy podzols in high rainfall (> 800 mm annual average) areas of south-western Australia. The pastures were subterranean clover (Trifolium subterraneum) or mixed subterraneum clover and serradella (Ornithopus compressus). Coastal superphosphate was made by adding rock phosphate and elemental sulphur to superphosphate during manufacture, as it came out of the den before granulation. One rock phosphate was a 50% mixture of apatite rock phosphate from Nauru and Christmas Islands, and which was also used to make the single and coastal superphosphate used in this study, and superphosphate made in Western Australia at the time these experiments started. The other rock phosphate was Calciphos, the fertilizer produced by heating (calcining), at about 500 °C, Christmas Island C-grade ore, a calcium iron aluminium rock phosphate. There were two types of experiments. In the three Type 1 experiments, levels of each fertilizer were applied annually. In the two Type 2 experiments, levels of fertilizer were applied once only to new plots in different years. Coastal superphosphate was the most effective fertilizer in the Type 1 experiments, with both rock phosphates and single superphosphate being equally effective. All fertilizers were equally effective in the Type 2 experiments. There were large variations in fertiliser effectiveness values between yield measurements in the same or different years. It is known that P leaches from freshly-applied superphosphate in these soils. The extent of this leaching probably varies between yield measurements affecting effectiveness values determined for all fertilizers because the effectiveness values were calculated relative to the effectiveness of single superphosphate. The humic, sandy podzols remain wet during the growing season, are acidic, and are known from laboratory studies to possess adequate hydrogen ions to cause extensive dissolution of North Carolina rock phosphate so that rock phosphates are equally or more effective than single superphosphate in these soils. When elemental sulphur in coastal superphosphate is oxidized to SO₄ hydrogen ions are produced which in previous studies has been shown to enhance dissolution of rock phosphate in biosuper, a mixture of rock phosphate and elemental sulphur.     

过磷酸钙含氟废水处理装置的工艺改进

针对含氟废水处理装置试运行过程中中和反应效果不佳、污水沉降时间不足等问题,采用机械搅拌强化中和反应,并投加絮凝剂提高沉降效率,确保了废水达标排放。     

Simulation of Fe-Al compounds developed during single superphosphate manufacture

In order to analyse iron phosphate complexes and gel-like phases encountered in the single superphosphate process, experiments were performed with a free-Al, Fe apatite crystal of Durango from Mexico phosphate rock and sulfuric acid. Reaction products were studied by X-ray diffraction and surface analysis methods namely X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that in a free Al, Fe-system, part of the Ca(H₂PO₄ )₂.H₂O (MCPM) forms before precipitation of any CaSO₄(CS) and gel-like phase such H₂SO₄.yH₃PO₄.xH₂O is formed. When iron is added, the precipitation rate of (CS) and (MCPM) increases and Fe₃(H₃O)H₈(PO₄)₆.6H₂O is formed. When Fe and Al are added, a gel-like phase is quickly formed with a molar ratio that changes with time and develops into crystalline compounds. The composition of this gel may be represented as a mixture of two phases: H₂SO₄.yH₃PO₄.xH₂O and a gel containing Al-Fe-Si.     

Obtaining granular NPK fertilizers from single superphosphate and urea

A laboratory study was conducted to elaborate methods for obtaining granular NPK fertilizers from mixtures of single superphosphate (SSP) with urea and potassium salts. Samples of products of various grades containing 32–39% fertilizer nutrients and some micronutrients (B, Cu, Co, Mo, Mn) were obtained and their characteristics determined. Instead of cured SSP the usage of a fresh den product was recommended to reduce environmental pollution. The best results were obtained by drying den superphosphate and neutralizing it with limestone before mixing it with other components. Granulation of mixtures should be carried out by the thermic method at 80–95°C, on account of the liquid phase from melting urea. The hardness of the granules obtained by this method, when stored in a dry room, remained satisfactory for 3 months.This paper is dedicated to the memory of Edgar Arumeel (1911–1993)     

Influence of calcium sulfate crystal size on the curing time of single superphosphate

Experiments were performed in order to test the influence of calcium sulfate crystal size on the rate of the reactions involved during the single superphosphate manufacturing process. Two different magmatic apatites were used, Durango (MEXICO) and Araxa (BRAZIL). After reaction with sulfuric acid solution, the crystal size was analysed by SEM. The chemical performances of the products were determined according to the fertilizer manufacturing standards. The results show that when 20–40 wt % sulfuric acid solutions were used, calcium sulfate crystal size increased up to 20 m. This fact can explain the reduced time of curing (some hours instead of several weeks) due to the absence of blocking of the reaction, related to a higher porosity of the precipitate and then an easier access of the acidic solution to the surface of the apatite.     

Comparison of single and coastal superphosphate for subterranean clover on phosphorus leaching soils

Coastal superphosphate, a partially acidulated rock phosphate (PARP), is being considered as an alternative fertilizer to single superphosphate for pastures in high rainfall (> 800 mm annual average) areas of south-western Australia. The effectiveness of single and coastal superphosphate, as P fertilizers, was measured in two field experiments using dry herbage yield of subterranean clover (Trifolium subterraneum). The experiments were started in April 1990 and were terminated at the end of 1993. In the years after P applications, soil samples were collected each January to measure Colwell soil-test P, which was related to plant yields measured later on that year, to provide soil P test calibrations.Relative to freshly-applied single superphosphate, the effectiveness of freshly-applied coastal superphosphate and the residues of previously-applied single and coastal superphosphate were less effective in some years (from 3% as effective to equally effective), and up to 100% more effective in other years. This large range in effectiveness values in different years is attributed to different climatic conditions. Soil P test calibrations were different for soils treated with single or coastal superphosphate. The calibrations were also different for different yield assessments (harvests) in the same year, and in different years. Consequently soil P testing can only provide a very crude estimate of the current P status of the soils.     

尿素过磷酸钙复肥生产工艺

介绍了尿素过磷酸钙（USP）复肥的主要生产工艺过程及条件,认为USP复肥是普通过磷酸钙（SSP）生产厂理想的升级产品。     

改善普钙产品质量的几点建议

本文针对目前某些普通过磷酸钙生产厂存在磷矿分解率不高、产品质量欠佳的问题,利用CaO—P_2O_5—H_2O三元体系相图从理论上进行了分析和讨论,并提出了几点改善产品质量的建议。     

增效过磷酸钙肥料的生产及其对钙的缓释作用

以过磷酸钙(SSP)为主要原料,氨化中和后转鼓造粒,在包膜油和包膜粉中添加植物生长调节剂和生物菌剂,进行包膜生产增效过磷酸钙肥料,并对其进行水培及土柱淋溶实验。结果表明,增效肥料在水中的初期(前3 d)溶出率(35.17%±0.41%)显著优于过磷酸钙(33.01%±0.79%),增效肥料的钙累积溶出率(51.22%±0.10%)显著高于过磷酸钙(48.62%±1.57%)。淋溶实验表明,增效肥料包膜后,对钙的初期释放可以起到缓释作用,其中第1天达到了显著水平,包膜前为(19.14%±0.53%),包膜后为(15.20%±1.11%)。缓释增效过磷酸钙肥料可以改善过磷酸钙的理化性质。