Comprehensive Utilization Of The Effective Constituents Of Serpentine

Serpentine is the general term for aquo magnesium-rich silicate minerals.There are abundant serpentine mineral resources in China.Its main components are magnesium silicate,meanwhile it often associated with iron,nickel,cobalt,chromium and a small number of platinum group elements such as platinum,rhodium,iridium,etc.In some serpentine mines,a large proportion of Mg²⁺is replaced by Al³⁺,Ni²⁺,Cr³⁺,Fe²⁺,Fe³⁺,Mn²⁺and other metal ions in the form of isomorphism,forming subspecies such as nepouite and greenalite.The theoretical chemical compositions of serpentine are:???MgO 29.30%⁴4.70%,SiO₂ 44.20%⁵7.37%,H₂O 13.10%,a small amount of FeO,Fe2O3,NiO when Mg displaced by Fe and Ni,associated Pd 0.01%.Serpentine can be produced into many industrial products,it is a highly promising kind of mineral resource.In this paper,the research of experiment and exploration was mainly on extraction and enrichment of serpentine's effective constituent,including the following aspects:1.Acid and alkali resistance of serpentine makes the reaction of acid leaching difficult to proceed.In this paper,the factors that affect the acid leaching reaction were studied in following four experimental schemes:?1?Serpentine powder reacted with different concentrations of hydrochloric acid directly;?2?Reacted with different concentrations of sulfuric acid directly;?3?After mixing with sodium carbonate in a certain proportion and calcining,then reacted with different concentrations of hydrochloric acid;?4?After mixing with ammonium sulfate in a certain proportion and calcining,then reacted with different concentrations of sulfuric acid.Filtered and dried the solid products after the reactions.Compared the progresses of the reactions by measuring the mass of the products.The effects of reaction temperature,concentration of acid and pretreatment of serpentine raw materials on acid leaching reaction were investigated.Considering the reaction conditions,the dosage of raw materials and the requirements of the equipment,scheme?3?was determined to be the best plan.2.A process of extracting and utilizing the elements of silicon,iron and magnesium in serpentine was designed.The effects of heating temperature,pH value,choice of lye and reaction time on the recovery of silicon,iron and magnesium and the purity of the corresponding products were investigated.The optimum reaction conditions to extract silicon,iron,magnesium and prepare high purity silica,iron oxide and light magnesium hydroxide were determined.Finally,the whiteness of silica product was 93.5%,the purity was above 95%,and the recovery rate of SiO₂ was 96.21%;The purity of iron oxide products was 99.72%,and the recovery rate of iron was 96.22%;The whiteness of magnesium hydroxide product was 96.8%,the purity was 99.4%,and the recovery rate of magnesium was 95.04%.The result shows that the scheme was a set of economical,environmental and green production process design.3.Three experimental schemes for extracting palladium from serpentine leaching solution were proposed but the results did not match the expectation.The possible causes of the results were analyzed.In order to investigate the causes,the compensation experiments were carried out with the substitution scheme.The expected results were successfully obtained.According to the results of the compensation experiments,the reason for the failure of the expected experiments might be the loss of palladium element in the early processing of serpentine.