复混肥几种配料体系中的成盐反应

从物理、化学的角度出发分析了几种复混肥配料体系在复混肥生产过程中混合物料间的化学反应.叙述了分别用氨、碳酸氢氨、石灰粉和钙镁磷肥等对普通过磷酸钙(或重过磷酸钙)进行改性处理的过程中发生的化学反应以及这些反应对混合物料的物理、化学性质的影响,这些中和剂在进行普钙(或重钙)的改性处理时各有优劣,应根据生产的实际情况慎重选择;尿素的缩合反应;尿素的水解反应及其影响;有硝铵存在的复混肥配料体系中混合物料间的放热反应;钾盐、复盐的置换反应及其对混合物料物化性质的影响.     

复混肥加工中化学反应的运用

阐述复混肥生产过程中如何恰当利用原料间的各种化学反应。例如提高物料黏性有利造粒;加入某些物质消除反应产生的液相;利用化学反应热蒸发水分减轻干燥负荷等等,以达到消除生产中的不利因素,提高产量、质量,降低消耗的目的。     

蒸汽团粒法复混肥生产中粉尘污染问题及对策探讨

粉尘污染是复混肥生产中普遍存在的问题,分析了蒸汽团粒法复混肥生产中产生粉尘的主要因素,分别是混合后的造粒物料可塑性差或配料不均衡、蒸汽量与造粒物料量的比例不适中、造粒工况和干燥温度控制不当,以及防尘除尘措施不到位,并针对这些因素提出了对策。     

关于中和处理过磷酸钙的计算

关于中和处理过磷酸钙的计算曾曼华（湖北省仙桃市磷肥厂）尿素——过磷酸钙系复混肥料是以尿素和过磷酸钙为基础的粒状肥料。由于过磷酸钙中有游离酸和磷酸一钙，尿素与其混合后发生的主要反应有：Ｈ＿３ＰＯ＿４＋ＣＯ（ＮＨ＿２）＿２＝ＣＯ（ＮＨ＿２）＿２·Ｈ＿３Ｐ...     

混复肥生产过程中的普钙氨化

一、普钙氨化的重要性在以普钙—尿素为基质体系的混复肥生产过程中,普钙改性——氨化是极为重要的工序,普钙氨化不好,甚至影响混复物料不能完成造粒过程;若氨化完善,则造粒顺利,而且可得到不胶结、不松散、不吸湿、不含游离酸的商品性混复肥。普钙不改性,直接与尿素混合,就不可能成粒。这是因为普钙与尿素发生下列反应:     

过磷酸钙预处理对复混肥生产的影响

过磷酸钙预处理对复混肥生产的影响刘运成（湖北天门化工总厂复混肥分厂）干法工艺生产氮磷钾粒状复混肥料的主要原料是尿素、氯化铵、氯化钾、硫酸铵、硝酸铵、过磷酸钙等。各种原料经过破碎、混合、加水造粒，然后干燥、过筛，尺寸过大的颗粒经破碎后再循环过筛，过小的...     

复混肥造粒用海泡石与磁土作为调理剂

复混肥造粒用海泡石与磁土作为调理剂谭丽光欧阳海涛（株洲市湘江氮肥厂４１２００５）中图分类号ＴＱ４４４本文将对团粒法生产尿素、过磷酸钙系列复混肥过程中易出现的几个主要问题进行讨论,以寻求解决的途径。１复混肥生产中易出现的问题对尿素、过磷酸钙系列复混肥,...     

复混肥生产中的原料预处理方法

复混肥料生产常用的基础原料有过磷酸钙、尿素、钙镁磷肥、硫铵、硝铵、硫酸钾、氯化钾等,其中,过磷酸钙和尿素是用的最多,用量最大的复混肥生产原料。目前,国内生产的过磷酸钙(简称普钙)一般含游离水10—18%,游离酸5～10%。这种普钙不适于生产中的破碎和造粒,因此,必须对原料普钙进行予处理,处理方法如下:     

复肥生产过程中缩二脲的生成研究

采用国家化工行业标准(HG 2095-91) - 涂层尿素中缩二脲含量的测定方法系统研究了复混肥生产过程中缩二脲的生成,通过实验研究分析发现,在影响缩二脲生成率的4个因素:物料加热温度、加热时间、物料中水份含量、物料中尿素的质量分数中,影响最显著的是尿素的质量分数.     

我厂复混肥生产中产生结疤的原因及解决措施

以尿素、磷铵、过磷酸钙、硫酸钾等原料用团粒法生产复混肥的过程中，烘干机、斗提机、卧式双辊链条粉碎机常产生结疤，分析产生结疤的原因是物料含水分和游离酸过高所致，并提出相应解决措施。     

Heavy metal contaminants in inorganic and organic fertilizers

Commercial phosphate (P) fertilizers contain small amounts of heavy-metal contaminants which were minor constituents in phosphate rock (PR). Animal manures and sewage sludges (biosolids) are the main organic fertilizers and the latter also may contain heavy-metal contaminants. Heavy metals in biosolids may be found in the inorganic form or may be organically complexed, which could affect their chemical reactions in soil. These heavy metals may accumulate in soil with repeated fertilizer applications. Cadmium (Cd) is the heavy metal of most concern because it may affect human health. Other heavy metals of possible significance are arsenic (As), chromium (Cr), lead (Pb), mercury (Hg), nickel (Ni), and vanadium (V). Some countries have set tolerance limits on heavy-metal additions to soil because their long-term effects are unknown. These limits usually are set for the tillage layer (surface 20–30 cm) of soil where most root activity occurs. Controls on heavy-metal concentrations in sewage biosolids and their maximum total and annual loading rates to soil have been imposed in some countries. Regulations also have been proposed for phased-in limits on maximum heavy metal concentrations permitted in P fertilizers, or they are already in effect. Most of the fertilizer regulations relate Cd limits to P concentrations, so P application rates dictate Cd inputs to soil. Regulations affecting sewage biosolids include a number of heavy metals, while those concerning P fertilizers only include limits on Cd at this time.     

化学肥料的结块及其防止

针对化学肥料结块的现状和危害,在探讨结块机理的基础上,论述了对化学肥料尤其是复混肥料进行防结块处理的必要性和方法,对防结块剂提出了用量微量化、成本低值化、应用多功能、环保无害化的要求.     

Agronomic and environmental aspects of phosphate fertilizers varying in source and solubility: an update review

This review discusses and summarizes the latest reports regarding the agronomic utilization and potential environmental effects of different types of phosphate (P) fertilizers that vary in solubility. The agronomic effectiveness of P fertilizer can be influenced by the following factors: (1) water and citrate solubility; (2) chemical composition of solid water-soluble P (WSP) fertilizers; (3) fluid and solid forms of WSP fertilizers; and (4) chemical reactions of P fertilizers in soils. Non-conventional P fertilizers are compared with WSP fertilizers in terms of P use efficiency in crop production. Non-conventional P fertilizers include directly applied phosphate rock (PR), partially acidulated PR (PAPR), and compacted mixtures of PR and WSP. The potential impacts of the use of P fertilizers from both conventional (fully acidulated) and non-conventional sources are discussed in terms of (1) contamination of soils and plants with toxic heavy metals, such as cadmium (Cd), and (2) the contribution of P runoff to eutrophication. Best practices of integrated nutrient management should be implemented when applying P fertilizers to different cropping systems. The ideal management system will use appropriate sources, application rates, timing, and placement in consideration of soil properties. The goal of P fertilizer use should be to optimize crop production without causing environmental problems.     

Needs for controlled-availability micronutrient fertilizers

Use of micronutrients for agronomic and horticultural crops has increased markedly in recent years. Increased use is related to higher nutrient demands from more intensive cropping practices and also from farming marginal lands. Most of the fertilizers used to correct micronutrient deficiencies are water- soluble inorganic sources or soluble organic products such as synthetic chelates or natural organic complexes. These fertilizers may react with soil to decrease their availability to plants. The rates of such chemical reactions may differ considerably with each micronutrient fertilizer and soil environment.Recommended micronutrient rates have been based on results of numerous experiments, and these rates vary with crop, soil, and other factors. The usual application rates (on an elemental basis) range from 1 to 10 kg ha^–1 for Cu, Fe, Mn and Zn; < 1 kg ha^–1 for B; and < 100 g ha^–1 for Mo.Because the metallic micronutrients (Cu, Fe, Mn, and Zn) generally are sorbed strongly by soil clays, they do not move significantly in soil. Hence, they are not leached readily from the zone of application to lower soil depths or into groundwaters. Mobility of these micronutrient cations is higher in sandy soils, especially with high leaching conditions. Therefore, their movement out of the root zone is possible under some situations. Significant residual effects of soluble Cu and Zn sources greatly reduce the need for controlled-availability Cu and Zn products. Controlled-availability Fe and Mn fertilizers have not been effective because the rapid oxidation of Fe and Mn and reactions with soil reduce their availability upon release.Because soluble B fertilizers form boric acid molecules in soil, they are mobile and subject to leaching conditions. While mobility of B is less than that of NO ₃ ^- -N in soil, field results have demonstrated loss of applied B from the root zone in sandy soils. Slightly soluble B fertilizers, such as colemanite and ulexite, and fritted B products (powdered glass-like materials whose solubility is controlled by particle size) have been used in sandy soils for some crops.Molybdenum requirements are much lower than those of the other micronutrients. Deficiencies generally are corrected by liming the soil or by seed or foliar applications, so there is little need for controlled-availability Mo fertilizers.Little research has been conducted on controlled availability micronutrient fertilizers. While fritted products are considered in this category, they are difficult to handle and only may be of value in supplying B under specific conditions. Coating soluble granular micronutrient fertilizers also has been attempted, but there are few reported results of their relative effectiveness in comparison with conventional fertilizers and application methods. New micronutrient products may be needed for specific conditions such as greenhouse-culture or container-grown crops, but plant needs also may be met by multiple applications of soluble sources.     

世界硫需求及硫肥状况

阐述世界硫肥的需求状况:到2012年世界农业缺硫量预计每年将达1 100万t,而亚洲和美洲将成为全球最严重的缺硫地区。环境污染控制、集约化农业生产以及低硫高浓度肥料的使用,加剧了全球范围内土壤缺硫状况。缺硫日益成为农业可持续发展和提高肥料利用率的限制因素之一,但也刺激农用硫肥的需求,为肥料工业开发新技术和新产品、开拓市场提供了契机。有3种硫肥,分别是:(1)硫酸盐基;(2)硫磺基;(3)液态硫基,其中硫酸盐基占绝大部分,其具有较好的理化特性,可直接、均衡为作物提供多种养分。本文介绍含硫肥料的种类、各种肥料的性能及目前世界上开发多种新型含硫肥料产品来适应和满足不同作物、土壤的需要。     

缓释肥料的开发

缓释肥料的开发途径有:①通过化学反应合成缓释肥料,如脲醛缩合物;②对化肥进行包膜,制成包膜肥料;③掺入阻硝化剂或脲酶抑制剂制成缓释肥。其在土壤中的溶解速度慢,硝化分解时间长,养分利用率高,是环保节能产品。     

聚合物包膜肥料养分控释研究进展

聚合物包膜肥料的养分控释机理研究对包膜肥料的开发与应用起着重要作用,国内外研究学者在Fick扩散定理的基础上建立了包膜肥料控释理论和多种数学模型,探索了影响养分释放的因素。聚合物包膜肥料按扩散机制释放养分。养分释放速度的控制因素主要有两种不同看法,一种是养分扩散速率控制,另一种是水蒸气渗透速率控制。肥料包膜层厚度、包膜材料吸水性、温度、水蒸汽压、土壤含水量等均影响养分释放。     

The role of isotopic techniques on the evaluation of the agronomic effectiveness of P fertilizers

Many isotopic techniques can be applied to determine the relative immediate and residual effectiveness of P fertilizers. Using isotopes as tracers, the percentage of utilization by plants of the P derived from a fertilizer can be determined. However this is only possible during the three or four months after the application. Therefore, the P fertilizers may be classified only according to their relative immediate effectiveness. To also evaluate residual effect, which can be observed when more P is applied than is removed with harvest, isotopes of phosphorus can be used. This residual effect is determined by comparing pool sizes of bioavailable soil P in soils with and without P fertilizer aged in soil. The bioavailable soil P pool may be analyzed according to three isotopic experimental procedures which give access to either the A value, or the E value or the L value. The aims, the similarities and the differences between these three procedures, are examined. Some of the theoretical and practical constraints of each method are described in this paper; they must be followed in order to obtain reliable information for agronomic purposes. A method involves measuring the rate of isotopic exchange of phosphate ions in soil-solution systems maintained in steady-state. It is now possible to predict the effectiveness of P fertilizers, whatever their chemical form when this method is applied on soil samples where P fertilizers were applied.This paper was originally submitted as part of the special issue on Evaluation of the Agronomic Effectiveness of Phosphate Fertilizers through the use of Nuclear Related Techniques edited by F. Zapata     

预中和-单管二次氨化技术生产DAP/NPK复合肥工艺

分析常压两步中和喷浆造粒工艺、预中和-转鼓氨化工艺、管式反应器工艺生产DAP/NPK的弱点,介绍为克服这些弱点而研究开发的预中和-单管二次氨化技术的主要工艺过程及该工艺的技术特点和比较优势.提供了贵溪化肥厂的试生产及其效益情况,若月产NPK产品2.5万吨,每月可增加经济效益140万元.