An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows： reaction temperature 85-...An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows： reaction temperature 85-95 ℃, oxygen flow rate 8-12 L/min, reaction time 210 min, the ratio of starch to water 1：5, 3.5 wt% of NaOH and 0.1 wt% of catalyst. The experimental results show that the concentration of hydrolysate-oxidaton product is 16-18 wt%. The powdered products were gained through dehydrated and powdered process using quadruple-effect evaporator, spray drying tower and guide shell mixer. The composting test indicates that the degradability of the oxidized corn starch can reach 76.4%. The complexation capacity of calcium ions reaches 108.5 mg per gram oxidized starch, and the detergency ratio （P） reaches 1.30 as builder.展开更多
Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative ...Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative depressants for a complex lead-zinc(Pb-Zn) ore rich in graphite(Gr-C) on a conventional mini pilot-scale flotation circuit. The reagents used were commercial and industrial grade starch; agro-based waste-sugarcane bagasse and charred(burnt) bagasse powder. The primary evaluation criteria were quality(grades) of lead and zinc concentrates, their recoveries(%), and graphite rejection(%) in the tails.Benchmark tests using nigrosine as graphite depressant showed 94.3% rejection of Gr-C. The results with commercial starch were found as effective with 93.8% graphite rejection. Furthermore, bagasse powder showed potential in improving product quality(36.4% and 65.6% Pb grade and recovery) with an intermediate effectiveness in graphite rejection(85.6%). The order of effectiveness in Gr-C rejection follows nigrosine % commercial starch > bagasse > industrial starch > charred bagasse. In addition, the effect these depressants on silver(byproduct) grade and recovery was also investigated.展开更多
文摘An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows： reaction temperature 85-95 ℃, oxygen flow rate 8-12 L/min, reaction time 210 min, the ratio of starch to water 1：5, 3.5 wt% of NaOH and 0.1 wt% of catalyst. The experimental results show that the concentration of hydrolysate-oxidaton product is 16-18 wt%. The powdered products were gained through dehydrated and powdered process using quadruple-effect evaporator, spray drying tower and guide shell mixer. The composting test indicates that the degradability of the oxidized corn starch can reach 76.4%. The complexation capacity of calcium ions reaches 108.5 mg per gram oxidized starch, and the detergency ratio （P） reaches 1.30 as builder.
基金The author is grateful to the management and staff of Center Research Development laboratory(HZL,Debari),India for their support with this research and permitting to publish the work.
文摘Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative depressants for a complex lead-zinc(Pb-Zn) ore rich in graphite(Gr-C) on a conventional mini pilot-scale flotation circuit. The reagents used were commercial and industrial grade starch; agro-based waste-sugarcane bagasse and charred(burnt) bagasse powder. The primary evaluation criteria were quality(grades) of lead and zinc concentrates, their recoveries(%), and graphite rejection(%) in the tails.Benchmark tests using nigrosine as graphite depressant showed 94.3% rejection of Gr-C. The results with commercial starch were found as effective with 93.8% graphite rejection. Furthermore, bagasse powder showed potential in improving product quality(36.4% and 65.6% Pb grade and recovery) with an intermediate effectiveness in graphite rejection(85.6%). The order of effectiveness in Gr-C rejection follows nigrosine % commercial starch > bagasse > industrial starch > charred bagasse. In addition, the effect these depressants on silver(byproduct) grade and recovery was also investigated.
