ABSTRACT In the present research work, the influence is evaluated of the sodium hydroxide concentration and the time of operation on the percentage (%) of the removal of arsenic present in a refractory auriferous concentrate from the northern region of Peru, using leaching Alkaline. To carry out of the test, the samples of concentrate of 200 g (20% solids) in a volume of 1 L. and with a grain size of -325 mesh (45um), at a temperature of 80°C, with addition of air and agitation, were subjected to different concentrations of sodium hydroxide 1.25 M, 1.5 M, and 1.75 M., and at different operating time levels of 1.5hrs. 2.5hrs. and 3.5hrs. to obtain the maximum percentage (%) of arsenic removal, using alkaline leaching. The mineralogical study of the sample of refractory gold concentrate concluded that despite having studied three polished sections to have a larger study area, no native go...