Study On Treatment And Reuse Of High Suspended Solids Circulating Water In Iron Ore Dressing

With the diminishing reduction of high-grade and easily-selected iron ore in China,more and more attention has been paid to the development and utilization of complex and difficult-to-select low-grade hematite in recent years.In order to adapt to the technological mineralogical characteristics of poor grade,complex structure and small grain size,a complex combined mineral processing process is often needed to obtain satisfactory separation technical indexes.The combined process of stage grinding-coarse fine classification-gravity separation and magnetic separation-reverse flotation has been successfully applied by many in a number of hematite ore dressing plants due to its unique technical advantages,and has obtained satisfactory selection indicators.However,the process also has many shortcomings.For example,the long process is not easy to control,the grinding efficiency is not high,the fine-grained iron minerals are not effectively recovered and so on.Especially in the current high requirements for mine environmental protection,the treatment and recycling of high-dispersion suspended solid wastewater has become a key problem related to the survival and development of mining enterprises.Sijiaying Iron Mine belongs to the large-scale Anshan-type iron deposit in China and even in the world.The main ore types are hematite quartzite and magnetite quartzite,all of which are lean iron ore.The total reserves of iron ore resources are 23.48×10⁸ t.In 2003,the company started to build the Sijiaying Iron Mine project,and the ore dressing plant with iron ore oxidizing reverse flotation technology was put into operation in July 2007.Many technical and economic problems such as the separation of oxidized ore,large consumption of water,large stripping ratio,and the stacking of tailings and waste stone are encountered in the production.The difficulties in the treatment of high dispersive suspended solids waste water have always plagued the development of the Sijiaying Iron Mine.The problem is becoming more and more serious in the production process.Under the current strict environmental protection requirements,it is obviously not easy to solve those problems with new water.It is necessary to dispose the existing circulating water to meet the recycling requirements.Based on the theoretical study of high-efficiency flocculation sedimentation of fine-grained high-dispersion silicate minerals,a variety of flocculants and their combinations are used to treat chlorite and quartz,which are the mainly difficult to settle in the high-dispersion beneficiation wastewater of Sijiaying.The flocculation sedimentation test and comparison of single minerals such as kaolinite showed that the anionic flocculants APAM-1 and APAM-2 had good flocculation effect on chlorite and kaolinite under strong dispersion system.However,there is basically no flocculation effect on quartz.Under the strong dispersion system,the cationic flocculant CPAM-1 and the chitosan quaternary ammonium salt HACC-102 have good flocculation effect on chlorite and quartz,but the flocculation effect on kaolinite is weak;Calcium ion promotes flocculation of precipitated silicate minerals of anionic flocculation APAM-1;The amphoteric flocculant C-PAM has certain effects on chlorite,quartz and kaolinite,and is the best for chlorite,followed by kaolinite and then quartz.The combination of yin/yang flocculant have a good effect on chlorite,quartz and kaolinite.The potentiodynamic test showed that the dispersed flocculation sedimentation of chlorite was closely related to its surface dynamic potential.The larger the absolute value of the dynamic potential of the chlorite surface,the stronger the dispersion of chlorite.Crystal structure studies showed that the chlorite fragmentation surface not only has Si-O bonds,but also many metal ion active sites,so that the chlorite has a staggered charged surface,so that anions,cations and amphoteric flocculants can be adsorbed to the surface of the chlorite.Meanwhile,the infrared spectroscopy test results also showed that the anion,cation and amphoteric flocculant all adsorbed on the surface of the chlorite,and the chlorite quickly flocculated and settled.Quartz has a negative charge in a wide range of test pH and no other cationic active sites on the surface,so the cation and amphoteric flocculant can adsorb on the quartz surface,thus promoting the rapid sedimentation of quartz,but the anionic flocculant cannot adsorb on its surface.It cannot promote the flocculation sedimentation of highly dispersed quartz particles,but under the overseas role of the Ca²⁺ion,the anionic flocculant can adsorb on the quartz surface to promote its flocculation sedimentation.The potentiodynamic test and infrared spectroscopy test showed that anion,cation and amphoteric flocculant could adsorb on the surface of kaolinite,but kaolinite sedimentation was also closely related to other factors.Kaolinite formed a dense floc under the treatment of anionic flocculant and the amphoteric flocculation,and the sedimentation speed is faster.Under the treatment of the cationic flocculant,kaolinite formed a loose floc,and the sedimentation is slow or even difficult to settle in this condition.Sijiaying circulating water has a high content of suspended solids.Polyacrylamide?PAM?is used as flocculant in the production.Therefore,there is a certain amount of PAM residue in circulating water.Both substances affect flotation and magnetic separation,and the content of suspended solids in water is well correlated with the flotation results,and the content of PAM content is well correlated with the magnetic separation results.The results of high-dispersion suspended solids circulating water treatment test at Sijiaying Iron Mine showed that the use of anionic flocculant alone has poor effect on flocculation sedimentation of high-dispersion suspended solids in Siejiaying Iron Mine,and high-dispersion suspended solids are enriched in circulating water.The ultra-high circulating water concentration once caused the production to stagnate,unable to operate normally,and caused the water overflow to affect the environment.Therefore,solving the problem of circulating water quality is the key to ensuring the normal production of Sijiaying Iron Mine,improving economic efficiency and protecting the environment.However,the combination of anionic flocculant APAM and CaCl₂ has a good effect on the flocculation sedimentation of the high-dispersion suspended solids of Sijiaying,and the dosage is small.The cationic flocculant has better flocculation sedimentation of the circulating water of Sijiaying high-dispersion suspended solids.Among those cationic flocculants,HACC-102 is the best,but its cost is high;The amphoteric flocculant has a general effect on the flocculation sedimentation of the high-dispersion suspended water circulating water of Sijiaying.In the response surface test,the interaction of suspended solids content,flocculant concentration and calcium ion concentration has a great influence on the beneficiation efficiency.The factors affecting the flocculation of APAM-1 and CaCl2 are:suspended matter content>flocculant concentration>calcium"Ion concentration".The flocculation treatment of circulating water after the overflow tank overflow water test showed that after the flocculation sedimentation treatment of circulating water with the combination of APAM-1 and CaCl2,the circulating water has basically reached the reuse requirements,and the mineral processing index is basically Stable,the annual iron ore concentrate increased by 480,000 tons,and the direct economic benefit reached 260 million yuan.