| Solid-liquid reaction is one of the most common methods for rock processing. With phosphate rock decomposing in the course of reaction, some resultants of reaction will diffuse and separate crystals out. The crystals may deposit on the surface of particles of solid reactant, coat the particles, form a layer of solid film and resist further reaction, if the crystallization happens on the surface of particles, which results in a decreasing reaction rate or even stopping reaction.Conventional measures for increasing the rate of solid-liquid reaction between phosphate rock and acid can be sorted into 2 aspects: one is adjusting reactive condition for larger size of crystal resultants to form a porous solid film; the other is decreasing solid-liquid interfacial tension for higher surface irrigation rate. Unfortunately, the measures have too strong correlation with raw material rock properties to extend over whole industry.Microwave, which has absorptivity and penetrativity, is the electromagnetic wave with 300 MHz ~ 300 GHz frequency. Liquid molecules will frequently change their direction with polar shift of microwave field, thus their ionization degree, ionic activity and permeability to solid film are spirited up, when they absorb microwave. The results in microwave "thermal effect" of friction and " non-thermal effect" of agitation among liquid molecules, disturb the crystal course of resultants of reaction, increase diffusion rate of resultants of reaction to liquid phase and contact probability between liquid molecule and particle of phosphate rock.It is the most important solid-liquid reaction that sulfuric acid orphosphoric acid decomposes phosphate rock in phosphate fertilizer production. By contrast with conventional reaction of acid decomposing phosphate rock, the influence of microwave on the reaction is discussed.Main research items include: 1) setting up a set of batch microwave reactor with multi-model cavity and a set of batch reactor by intelligent temperature control system; 2) researching isothermal and non-isothermal kinetic of sulfuric acid decomposing phosphate rock under the condition of microwave or not; 3) determining some properties of liquid reactant in acid -rock system with microwave enhancement; 4) discussing the influence of microwave heating and electric heating on crystal course; 5) simulating experiment of 32P tracer for distinguishing the permeability to solid film with/ without microwave irradiation.The results show that under a certain condition, microwave can prompt the decomposing reaction of acid-phosphate rock, accelerate reactive rate; improve electrical conductivity and ionization degree of liquid reactant sulfuric acid or phosphoric acid, raise the temperature of phosphate rock slurry and drive water evaporating; enhance crystal deposit of resultants of reaction, grain refining and homogenization, and keep original crystal habit, crystal structure and component; increase the activity of molecule and amount of free activated molecule, increase the permeability of phosphoric acid molecule and ion to porous solid media; microwave can also bring "thermal effect" and "non-thermal effect".Based on the data from the experiments of isothermal kinetic of sulfuric acid decomposing phosphate rock under the condition of microwave or not, 2 mathematic models were established: Microwave: Heating: Where, T rreactive temperature, K; t?reactive time, min; x ?percent conversion, % ; R-8. 314 J/(m ?K).Meanwhile, the homotropic effect between activation energy andpre-exponential factor was discovered under the action of microwave, dual control of microwave prompting and inhibiting action on reactive rate influences the acid-rock reactive system. When reactive temperature is more than 40℃, the reactive rate of acid decomposing phosphate rock with microwave is higher than that without one. After reactive temperature is more than 70℃ , the ratio of available diffusion coefficients with and without microw...
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