Bioflocculant's Application During The Process Of The Comprehensive Utilization Of Acid Slag

Acid slag is a solid waste that produced by gold epurating technique—vitriol roasting measure. The comprehensive utilization can not only bring us economic benefits but also control the cinders' pollution. Based on an investigation of present utilization and recovery of Acid slag, compared with the experience of utilizing cyaniding slag and sour slag, according to the real experiment condition, the iron oxide red have been made by calcined iron salt and seed crystal.During the processes of vitriol lixiviating, impurities purging and iron oxide red preparing, we found that there were many suspend granules in the admixture produced by the processes. By added flocculants we can separate the granules from liquid, and then the comprehensive utilization of acid slag could be carried out.The bioflocculant would not do harm to people and environment compared with other flocculants. We obtained a bioflocculant LMBF-1 by fermentable cultivating Aspergillus niger van Tieghem, and have done some experiments to study the flocculating characteristics of it. The flocculating experiment showed that the suitable pH value was acidity, and CaCl₂ facilitated the flocculation activity of the bioflocculant. The temperature has little influence on flocculating efficiency.The flocculating experiment of the admixtures between different flocculants indicated that: The LMBF-1 showed a best perfermance when used to flocculating vitriolic lixiviate admixture, and the best dosage is 3ml/100ml; The bioflocculant should be used associated with chemical flocculant when flocculating impurities purgded admixture, and the dosages are: 15ml Aluminium polychlorid+1ml LMBF-1,10ml Polyferric sulfate+2ml LMBF-1 or 5ml Polyacrylamide+1.5ml LMBF-1.The quality examination showed that the quality of iron oxide red produced by calcined iron salt achieved the standard of GB 1863-89(the third class). The iron oxide red produced by seed crystal achieved the standard of HG/T2574-94(the first class).The XRD indicates that the product crystal isα-Fe₂O₃, SEM proved that the granule of the product is global, and the granules distribute uniformity.In order to have an advanced understanding of LMBF-1, we studied the mechanism of LMBF-1. Analytical experiments approved that the major constitutes of LMBF-1 were polysaccharide but not protein and nucleic acid. The bioflocculant contained carboxyl and it was a anion flocculant. The purification experiment showed that the output of LMBF-1 is about 0.84g/L.The utilization of acid slag to prepare iron oxide red can not only control the cinders pollution but also can supply new technology and new material. When used to flocculating vitriolic lixiviate admixture and impurities purged admixture, bioflocculant LMBF-1 not only had a good performance but also obviously reduced the damages brought by inorganic flocculant and organic macromolecular flocculant. It has preferable social, economic and environmental benefits.