| Yellow phosphorus is a fundamental raw material in numerous fields.The yellow phosphorus is produced with reduction of phosphorus ore by carbon and depending on electricity to heat using silica as fluxing agent and it is washed and refined to gain elemental phosphorus.In general,the operation temperature is controlled at among 1350 to 1450? and electrical compution is 13000-15000 kW·h to produce 1 t ylow phosphorus,so it is a energy-intensive industry in an electrical furnace.The soluble potassium resource is scarce while insouluble potassium ore especially K-feldspar is abundant in China.Potash fertilizer is essential as a agricultural producer.Based on the principle of production yellow phosphorus,the idea that fluxing agent of silica is substituted using potassium ore in phosphorus furnace is proposed.The way opens up a new way for the comprehensive utilization of yellow phosphorus in electric furnace and potassium ore because it can not only reduce energy consumption of yellow phosphorus production,but also co-produce potash fertilizer that alleviates the shortage of potash fertilizer ascribing to characteristic of forming lower eutectics.To simplify the study,phosphate ore is replaced using CaO based on the forming mechanism of slag in phosphorus furnace.Fluxing agents of SiO2,silica.K-feldspar,nepheline syenite and CaO are mixed according to different acidity values and the melting temperature and vicosity are measured.And the slagging mechanism of phosphorus furnace is initially explored.To verify the superiority of fluxing repacment.high temperature reaction from the mixture of coke,phosphate ore and different fluxing agents is implemented to determine convension rate of yellow phosphorus,gasfication rate of potassium and flow temperature of residue.Thermodynamic study CaO-silica and CaO-potassium ore reveals that potassium ore can reduce reaction temperature of phosphorus furnace slagging.The study of meltbility,indicates that melting point of SiO2 increases by of 49.5?,K-feldspar and nepheline syenite can reduce melting point by of 73.5? and 257.2?.respectively.The results reval that spread-out area of SiO2 is 0.49 times of silica.K-feldspar and nepheline syenite systems are 1.54 and 7.49 times of silica.respectively under the same reaction temperature and time through spread out areas of different flusing agents at high temperature to research the viscosity of slag.Combined with XRD and TG-DSC analysis,CaSiO and Ca2SiO4 are generated for SiO2-CaO,silica-CaO and potassium feldspar-CaO in calcinations temperature of 900?.At 1300?.diffraction peak intensity of calcium silicate salt is strong for SiO2-CaO system and silica-CaO system has a small amount of vitreous body.As for potassium feldpsra-CaO system.CaAl2Si2O8 and Ca2Al2SiO7 are generated at 1000? and residual calcium salt is melted to form a liquid state resulting in main diffraction peak of KAlSiO4 at 1300?.While for nepheline syenite-CaO system,the Ca2Al2SiO7 and Ca12Al14O33 are generated at 900?.peak of KAlSiO4 is main characteristic peak at 1200? and the crystal state of nepheline syenite-CaO system is changed from crystalline to amorphous in 1250 ?.Therefore,potassium ore especially nepheline syenite can reduce melting point in phosphorus furnace.Based on the above study,the convension rate of yellow phosphorus different fluxing agents-coke-phosphate ore is researched.The results reveal that the phosphorus convension rate of silica system is 30.85%at 1300°C.K-feldspar system is 38.7%and 89.62%at 1100? and 1300?.respectively.While it is 86.56%for nepheline syenite system at 1100?.The study of gasfication rate of potassium for potassium ore-phosphorus ore-coke indicates that gasfication rate of potassium of K-feldspar and nepheline syenite systems is 81.57%and 98.57%at 1100?,respectively attributing to the characteristic of easy to sublimate of K2O.The results to study of flow temperature from residue indicat that flow temperature of residue from K-feldspar system is 1405? at 1300?.while it is 1401.7? for nepheline syenite system at 1100?.XRD analysis of residue reveals that Ca5(PO4)3F and SiO2 is main characteristic peaks for SiO2 system,small amount of calcium silicate is formed for silica system,small amount of vitreous body existes for K-feldspar,while the crystal state of nepheline syenite system is changed from crystalline to amorphous at 1300?. |
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