Preparation Of Nano-powder

In this paper, the chemical methods to get superfinegold colloidal sols were studied. In an acidic aquamedium, the concentrated chlorate gold solution wasreduced into sphere-shaped superfine gold powder withthe maximal size less than 20nm when using ascorbicacid as reductant. During the reduction process, PVP waschosen as dispersant. First several kinds of reductant werecompared, then the factors that affect the particle size ofgold and reduction efficiency were studied throughsingle-factor and orthogonal experiments. These factorsare the concentrations of reductant and those of thedispersant, pH value, and the way to add reductant. Inaddition, the methods to separate gold from gold colloidalsols were studied.The superfine gold produced with this method canbe used in the biological mark and the measure of proteinconcentration, the modifying of biosensor and the studyof optical material.The advantages of this method possesses are asfollows:1 ) Being produced in room temperature, no agitating,no resolve, no toxicity and pollution.2) High productivity, rapid speed, low cost, easy toindustralize.