Study On The Technological Conditions For The Comprehensive Utilization Of Valuable Elements Of Yiyang Jiangxi Serpentine Tailings

In this paper, technological conditions of the preparation of Light magnesiumoxide,Precipitated silica, Yellowironoxide have been studied, using the yiyangJiangxi serpentine tail as raw material. The main conclusions have been obtained asfollows:1. Taking the H₂SO₄of Pure analysis as acid infusions, the first step acidleaching technological conditions were optimized as follows: acid leachingtemperature95°C, acid leaching time5h, weight concentration of the sulfuric acidsolution40%and liquid-solid ratio4.5:1. At this condition, the average leachingrate was99.18%.2. Using the "secondary circulating acid leaching" process, the first step acidof10%H₂SO₄leaching technological conditions were optimized as: liquid-solidratio5:1, leaching time5h, acid leaching temperature95°C; the second step acid of20%H₂SO₄leaching technological conditions were optimized as: liquid-solid ratio6:1, leaching time5h, acid leaching temperature95°C; then, take the20%Titaniumdioxide absorbed as acid infusions, the "secondary circulating acid leaching" routewas feasibility by experiment, the verification results showed that the averageleaching rate of all was96.86%（>95%）, the average free acid quality in acidleaching filtrate was1.45%（<1.5%）.3. The impurity technological of crude magnesium sulfate solution wasoptimized as:25mL diluted10times of crude magnesium sulfate solution for theamount of hydrogen peroxide40mL, the purify pH8.5.4. The appropriate technological conditions of precipitating magnesium reaction was:concentration of the sodium hydroxide solution0.5mol/L, aging time60min, reactingtime25min, reacting temperature95℃； the appropriate technological conditions ofcalcinating reaction was: calcinate temperature500℃, calcinate time4h. The test resultsshowed that each index of light magnesium oxide were in line with national standards（HG/T3928-2007）.5. The appropriate technological conditions of inoculating crystal reactionfor preparing yellowironoxide was: ventilation flow80mL/min, pH value2.5—3.5,oxidation time8h. The iron oxide yellow sample was pure Orthorhombic phase by XRD analysis.6. The appropriate technological conditions of alkaline leaching reaction was:weight concentration of the sodium hydroxide solution25%, reacting time0.5h,liquid-solid ratio6:1, reacting temperature85℃. At this condition, the averageleaching rate of activity silica was99.18%.7. The appropriate technological conditions of precipitating silica reaction was:reacting temperature90℃, aging time60min, ventilation flow of carbon dioxide90mL/min. At this condition, the average yield of silica was99.67%, the test resultsshowed that each index of precipitated silica were in line with national standards（HG/T3061-1999）.8. The Dynamic model of serpentine sulfuric acid leaching process has beenpreliminary studied and determined that its control step was chemical reactioncontrol of Level2reaction model; the apparent activation energy of acidleaching Ea=66.6kJ/mol.