Surface Charge Characteristics And Mechanism Of Slime Mineral Particles

Coal is in a dominant position in energy consumption system and its dominance remains unchanged over an extended period in the future. The twelfth Five-Year Plan clearly required:" to use energy resources in reason, to improve energy efficiency of processure, to establish a clean and economy energy industrial system". But coal washing and processing is the technology source of clean usage,and it is necessary to produce3m3coal slurry washing one ton coal,so, it is the key factor for "realizing clean coal usage"to solve the problem of slime water or no.The paper uses SEM、XRD and industry analysis methods to analyse the mineral compositons, occurrence form and clay characteristics of different density and particle level of raw coal from Dingji Preparation Plant in Huainan city to master that the major mineral compositions are kaolinite and quartz with fine particles form scattered in raw coal. It is that raw coal mineral content increases gradually with the increase of coal density and the particles distribution property of mud broken from raw coal presents "two large head and small middle" for raw coal of different density level. For different particle size level raw coal, it is known that mineral content reduces first increases after with the decrease of raw coal particle size and reaches minimum amount in the grain size of0.5mm, and the particles distribution property of mud broken from raw coal presents "big tail, small head".The surface negative charge of slime particles is the main reason to keep highly dispersivity and stability, and the study shows that the main reasons of particle surface charged are priority dissociation(or solution), adsorption and inonization, lattice replac--ement etc. There are a lot of-SiOH with the hydrationon the quartz particle surface, and that the distribution of OH-or H+changes at different pH values will Influence the electrical characteristics of the particle surface. The electrical properties and quantities of the kaoline particle surface are approximatly decided by the charge sum of bedding surface and head face.there are a lot of Si-O and Al-O that can generate Si-OH and Al-OH on the kaoline particle surface, and the electrical properties of the kaoline particle surface are affected by pH value:(1)the electrical properties of bedding surface:①surface positively charges in the acidic medium,②surface negatively charges in alkaline medium;(2) the electrical properties of head face:①hen low pH value, the head face positively charges;②the head face don’t charge in a neutral and weak acid medium;③the head face negatively charges in alkaline medium.The research in the influences of stir intensity, pH value, soaking time, water hardness and different valence cations on particle surface electric potential of coal associated kaolin, quartz, clean coal and theirs mixture shows that the mineral particle surface electric potential absolute value both increases early and then tends to decrease as the stir intensity and soaking time increase, both decreases with the water hardness and cation valence increasing, in addition, the zeta potential absolute value of a single mineral particles surfaces appear the maximum value at pH=8or so, and the zeta potential absolute value of mixture mineral particles surfaces appear the maximum value at pH=10or so with the increase of pH value, subsequently level off. It can perfect slim mineral particles basic dispersion theory in water, and provide a theoretical basis for coal preparation plant tochoose pharmacy, improve pharmacy adding system, better Slime water treatment process,so it is industrial applications.