The effects of different treatments of blank reagent(quartz sand),weight of quartz sand,weight of soil and digestion temperature on the detection results of soil organic matter by chemical oxidation method are studied.The results show that quartz sand,which is crushed through a 0.250 mm sieve and burned,is more stable,the recommended sample weight is 0.2-0.3 g;When the volume of ferrous sulfate solution consumed by soil samples is more than 1/3 of the volume consumed by quartz sand,there is no significant difference in the influence of soil sample weighing amount and digestion temperature on the determination of organic matter content in soil samples within the experimental range.
The study is conducted in tomato greenhouse in Damiao Town,Songshan District,Chifeng City,Inner Mongolia to evaluate the comprehensive effects of bio-organic fertilizer,saline-alkali resistant soil conditioner and functional water-soluble fertilizer package fertilization technology on tomato yield and soil remediation.The results show that compared with traditional treatment,the soil remediation technology reduces manure input by 25％and decreases soil available phosphorus and EC.It also significantly increases tomato yield by 5.93％-18.30％and promotes tomato quality and income.In conclusion,the combination of bio-organic fertilizer and soil conditioner is more effective for the greenhouse soil remediation.
Plant growth regulators are a class of chemical synthetic substances with physiological activities similar to plant hormones,which can regulate physiology and metabolism of plant,increase crops yield and improve agricultural products quality.However,the recessive addition of plant growth regulators in fertilizer creates a threat to the safety of agricultural products.The types,applications in agriculture,determination in fertilizers and the development trends of common plant growth regulators are reviewed,aiming to provide a new idea for the application of plant growth regulators in agriculture.
Phosphate rock as the main raw material for phosphorus chemical industry,plays an important role in the development of the national economy.The current situation of phosphate rock industry in China in the past 5 years and the development trends of the phosphate rock industry in the future are introduced.The phosphate rock in China is abundant but with low grade,and its distribution is uneven.In 2022,the phosphate rock reserves are 3.69 billion tons,with the reserves in Yunnan,Guizhou,Sichuan and Hubei provinces accounting for 92％;In the past five years,the yield of phosphate rock has steadily increased,reaching 108.114 8 million tons in 2022;The consumption has increased significantly in the past two years,with an apparent consumption of 107.6 million tons in 2022 and a self-sufficiency rate of 100％for phosphate rock;The price of phosphate rock has started to rise significantly in recent years,with the average price of phosphate rock rising to 1 056 RMB Yuan/t in 2022;There are high barriers and fierce competition among enterprises;The phosphate mining technology suitable for its own resource endowment is developed,effectively improving mining and beneficiation rates.China's phosphorus resource reserves will be not lacking in the short term,but the supply of phosphoate rock will still be tight in the short term;In the long run,the supply and demand of phosphate rock will return to normal;The core competitiveness of phosphorus chemical enterprises in future lies in the planning of product chains.
Compound fertilizer industry in China has undergone decades of development,and market recognition of compound fertilizer products has been increasing year by year.At present,the mainstream production processes for compound fertilizers are slurry method,pellet method,high tower method,extrusion method,and other production processes.The granulation mechanism,process flow,advantages and disadvantages of each production process are summarized,and the product quality and comprehensive energy consumption of various processes are compared and analyzed,aiming to provide some ideas for the transformation and upgrading of compound fertilizer production enterprises under the"dual carbon"background in China.
Using calcium formate and magnesium formate prepared by carbonylation of industrial tail gas rich in CO as raw materials,the suspension system of high concentration formate is developed.The types,compounding ratio and dosage of dispersant are studied and analyzed by using flow point method,surface tension method and sedimentation method,combined with Zeta potential and system viscosity.Taking the suspension system prepared in laboratory as the research object,the adsorption characteristics of dispersant on the surface of raw material particles are characterized and analyzed by FTIR.The results show that the optimum dispersant composition of formate suspension system with 60％solid content is carboxylate 7025+methyl methacrylate 1269 with the total amount of 5％(m(7025)∶m(1269)=7∶3).FTIR analysis shows that there is a strong hydrogen bond between the dispersant molecule and the raw material surface.The research results lay a theoretical foundation for the application of dispersant in the research and development of suspension fertilizer,and provid a product basis for the application and marketing of formate,a by-product of industrial tail gas,in the direction of suspension fertilizer.
The phosphorus-containing sludge is treated with mixed waste acid containing sulfuric acid and phosphoric acid.The effects of process conditions on the leaching rate of phosphorus,nickel and copper,the content of sulfate in the leaching solution and the content of moisture and total phosphorus in the leaching residue of calcium sulfate dihydrate are studied.The results show that the optimal conditions for leaching process are as follows:the mass ratio of sludge and acid is 1.25,additive amount of crystallization inducer A is 5％,concentration of phosphorous-containing sludge slurry is 500 g/L,leaching time is 30 min and leaching temperature is room temperature.Under the above optimized conditions,the leaching rates of phosphorus,nickel and copper can reach 98.65％,99.37％and 99.52％respectively.The sulfate content in the leaching solution can be reduced to 2 640 mg/L,the moisture content of calcium sulfate dihydrate is 23.91％,the purity can meet the requirements of class Ⅱ products in GB/T 23456-2018,and the leaching toxicity results are lower than the limit values in GB 5085.3-2007.
Using minerals and solid waste as substitutes for desulfurizers,a deep coupling process of flue gas desulfurization,mineral processing,and solid waste disposal is an effective way to reduce desulfurization costs,achieve solid waste reduction,meet SO2 emission standards,and recycle flue gas and solid waste.The desulfurization slurry is prepared with phosphate rock and waste for flue gas desulfurization.The process technology of phosphate rock slurry desulfurization is described,and the economic advantages are analyzed through case studies,the factors that affect its promotion and application are summarized.
In order to reduce the production cost of DAP,the production process has been improved.By adding by-product ammonium sulfate of thermoelectrics device to replace some sulfuric acid for adjusting product nutrient content,using slag pond water to replace process water and sulfuric acid for supplementing tail gas washing system,and adopting DCS system to accurately control the amount of colorant,the production cost of DAP has significantly decreased.It is expected to save 23.033 million RMB Yuan/a,and the production cost has been decreased by 57.58 RMB Yuan/t,improving the company's market competitiveness of DAP products.
The filter residue is a by-product of industrial MAP with WPA as raw material,and its comprehensive utilization is one of the problems that the phosphorus chemical manufacturer needs to solve.The research status of the comprehensive utilization technology of industrial MAP filter residue is introduced,and some improvement directions on reducing the amount and improving the physicochemical properties of filter residue are proposed based on the existing problems of the utilization technology of filter residue.
In order to improve the production efficiency of wet-process phosphoric acid,reduce the loss of phosphorus resources,and reduce production costs,the application effects of different ionic polyacrylamide on slurry thickening and reaction slurry filtration process are explored through experiments.The results show that nonionic polyacrylamide has the best application effect on the thickening process of phosphate slurry,which can achieve a concentration of 62％-64％in the thickened slurry;The application effect of anionic polyacrylamide on the filtration process of phosphoric acid reaction slurry is the best,the water-soluble phosphorus content of filtered phosphogypsum is 0.10％-0.18％,and the free water content is 24％-27％,all of which are better than the production control indicators.This study provides a reference for selecting additives for slurry thickening and reaction slurry filtration in the production process of wet-process phosphoric acid.
The advantages and disadvantages of common production methods of agricultural ammonium polyphosphate are analyzed.The exploratory experimental research on the production of DAP containing polymerized phosphorus,as well as its agricultural application effects are introduced.The production technology of DAP product containing polymerized phosphorus relying on the existing ammonium phosphate plant is proposed.Its technical route is introduced,and the suggestions for application of this technology are proposed.
Fertilizer grade APP is a new high-end slow release water-soluble fertilizer,which is characterized by high nutrients,full solubility,slow release and increased efficiency.Available phosphorus in fertilizer grade APP is determined by volumetric method quickly,the results are consistent with the standard method,the relative standard deviation is 0.12％.The method is simple to operate,time-saving,and has high accuracy and precision,greatly improving detection efficiency.
In response to the problems of a wet-process phosphoric acid tail gas washing system,such as large footprint,poor washing effect,multiple equipments,high energy consumption,high maintenance costs,and difficulty in management,a new type of environment friendly washing tower with an integrated two tower structure is designed.Its structure and workflow,as well as its application in tail gas washing systems are introduced.This new water-saving and environment friendly washing tower has a compact structure,a small footprint,and a special internal demister structure;By using this tower,the F content in the tail gas is reduced from 10-11 mg/m3 to around 5 mg/m3,meeting environmental requirements.The process water consumption is reduced from 260 m3/h to 245 m3/h.The water-saving effect is obvious,and the goal of water-saving and environmental protection is fully achieved.
During the iron phosphate production with ammonium method,a large amount of mother liquor and washing water are generated,which contain a large amount of NH4+and SO42-.Suspended iron phosphate and metal ions such as iron,magnesium,calcium and manganese are removed through pre-treatment,and then demineralized water with a conductivity≤10 μS/cm is prepared through ultrafiltration and reverse osmosis technology.The demineralized water is used in the iron phosphate device as washing water and raw material dissolution water;The concentrated brine is sent to MVR for evaporation crystallization to separate ammonium sulfate products.The ammonium sulfate products are produced by concentration and crystallization of wastewater from iron phosphate production with ammonium method,achieving zero discharge of wastewater and increasing economic benefits.
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采用电感耦合等离子体发射光谱技术建立了磷精矿中磷、镁、钙、铁、铝、钾、钠、硫元素的测定方法.样品前处理采用微波消解,该方法灵敏度好,检出限在0.003 4～0.064 5μg/mL;标准曲线线性良好,相关系数均高于0.999;精密度好,相对标准偏差≤8.77％(n=6);准确度高,加标回收率在97％～101％.该方法简单、快速、高效,可用于磷精矿中8种元素的同时快速测定.
有效活菌数是衡量颗粒微生物菌剂质量的重要指标.通过实验研究颗粒微生物菌剂水分、储存温度、光照对有效活菌数的影响.结果表明:随着颗粒微生物菌剂水分升高,有效活菌衰减加快,菌剂w(H2O)为5.0％、15.0％、25.0％时,存放60d后有效活菌分别衰减3.6％、9.1％、21.8％;随着储存温度升高,有效活菌衰减加快,在5、20、35℃存放60d后,有效活菌分别衰减3.6％、5.5％、12.7％;当菌剂在室外储存,阳光直射条件下9d有效活菌衰减41.8％,而避光存放则基本不衰减.为了减缓有效活菌衰减,提高颗粒微生物菌剂产品效果,用户应挑选水分较低的产品,同时尽量低温储存,避免阳光暴晒.
云南云天化红磷化工有限公司8万t/a合成氨装置即将停产,届时磷铵装置将无气氨来源,为此公司开展了磷铵装置气氨供给改造.通过计算气氨需求量、液氨蒸发所需热量以及分析热源,确定以磷酸浓缩装置蒸汽冷凝水作为氨蒸发的热源.改造后,在解决磷铵装置气氨供给问题的同时,将生产过程产生的废热有效再利用,提高能源利用效率,每年可节约费用514.61万元,带来较大的经济、环境和社会效益.
