基于混料设计和响应曲面法的云南某铜尾矿选铋工艺参数优化

Optimizing Process Parameters of Bismuth Flotation for a Copper Tailings in Yunnan Based on Mixture Design and Response Surface Methods

某铜选厂尾矿试样中铋品位为3.94%,铋主要以自然铋的形式存在,其次为黄铜矿、方铅矿中铋。针对试样性质特点,采用浮选工艺流程回收铜尾矿中的铋。为进一步优化浮选指标,首先以乙硫氮和丁基黄药用量为自变量,铋的回收率为因变量建立混料模型,确定组合捕收剂乙硫氮和丁基黄药的最优配比。在此基础上,利用中心复合设计进行响应曲面设计,以磨矿细度、硫化钠用量、碳酸钠用量、组合捕收剂用量为自变量,铋的回收率为因变量,建立4因素5水平数学模型。然后按模型设计试验进行1次粗选浮选试验,对试验结果进行方差分析,验证模型的可靠性。最后依据响应曲面法确定的最佳浮选条件进行"1粗3精2扫"浮选闭路试验。结果表明:(1)在磨矿细度为-0.074 mm占85%、氧化钙用量为4 kg/t、硫化钠用量为150 g/t、碳酸钠用量为900 g/t、25号黑药用量为100 g/t、组合捕收剂总用量为200 g/t的条件下,组合捕收剂乙硫氮和丁基黄药的最优配比为4∶1。(2)方差分析模型的P<0.05,磨矿细度和硫化钠用量对铋的回收率影响显著;响应曲面法确定的最佳粗选条件为磨矿细度-0.074 mm占86%、硫化钠用量140 g/t、碳酸钠用量750 g/t、组合捕收剂用量250 g/t,预测铋的最大回收率为83.77%,实际铋的回收率为83.85%。(3)根据响应曲面法确定的最佳浮选条件,采用"1粗3精2扫"的闭路浮选试验,获得精矿铋品位24.47%、铋回收率79.25%的铋精矿,铋回收率较原浮选闭路流程提高近2个百分点。研究结果表明混料设计和响应曲面法可用于优化铋浮选的工艺参数,具有较高的可信度。

The grade of bismuth in the tailings of a copper concentrator is 3.94%.Bismuth mainly exists in the form of natural bismuth,followed by that in chalcopyrite and galena.According to the characteristics of samples,the flotation process was adopted to recover bismuth from copper tailings.In order to further optimize the flotation indexes,a mixture model was established with the amount of ethylthionitrogen and butyl xanthate as independent variables and bismuth recovery as dependent variables to determine the optimal ratio of ethylthionitrogen and butyl xanthate firstly.On this basis,the central composite design was used to design the response surface,taking grinding fineness,sodium sulfide dosage,sodium carbonate dosage and combined collector dosage as independent variables and bismuth recovery as dependent variables,a four factors and five levels mathematical model was established.Then,a roughing flotation test was carried out according to the model designed test,and the test results were analyzed by variance analysis to verify the reliability of the model.Finally,according to the optimal flotation conditions determined by response surface method,the closed-circuit flotation test of"one roughing-three cleaningtwo scavenging"was carried out.The results show that:(1)under the conditions of grinding fineness of-0.074 mm accounting for 85%,calcium oxide dosage of 4 kg/t,sodium sulfide dosage of 150 g/t,sodium carbonate dosage of 900 g/t,No.25 dithiophosphate collector dosage of 100 g/t and total combined collector dosage of 200 g/t,the optimal ratio of combined collector was diethyldithiocarbamate with butyl xanthate for 4∶1.(2)The P value of the variance analysis model is less than 0.05,and the grinding fineness and sodium sulfide dosage had significant influence on the recovery of bismuth.The optimum rough flotation conditions determined by response surface method were grinding fineness of-0.074 mm accounting for 86%,sodium sulfide dosage of 140 g/t,sodium carbonate dosage of 750 g/t,combined collector dosage of 250 g/t,the maximum predictive recovery rate of bismuth was 83.77%and the actual recovery rate of bismuth was 83.85%.(3)According to the optimum flotation conditions determined by response surface method,Bismuth concentrate with a bismuth grade of 24.47%and bismuth recovery rate of 79.25%was obtained by using the closed-circuit flotation test of"one roughing-three cleaning-two scavenging",the recovery was nearly 2 percentage higher than that of the original closed-circuit flotation process.The results show that the mixture design and response surface method can be used to optimize the process parameters of bismuth flotation,and has high reliability.