【作者】 王怡；

【导师】 邓荣东；

【作者基本信息】 福州大学 ， 矿物加工工程， 2023， 硕士

【摘要】 铜精矿中砷的存在不仅会影响铜精矿的冶炼,而且还会污染环境,对人体健康造成危害。铜蓝和硫砷铜矿都是硫化铜矿物,物理化学性质相近,在浮选过程中均会进入铜精矿,造成铜精矿砷含量超标。假如能够实现这两种矿物的分离,将铜精矿分为高砷精矿和低砷精矿两个产品,将有助于提高铜精矿的综合计价系数,增加选厂经济效益。本论文以铜蓝和硫砷铜矿为研究对象,探究了两种矿物晶体结构及性质差异。在此基础上开展单矿物试验,考察了常见离子和不同调整剂对铜蓝与硫砷铜矿浮选分离的影响,并在人工混合矿和实际铜精矿浮选试验中进行验证。结合Materials Studio模拟、接触角测量、傅里叶红外光谱、扫描电镜和X射线光电子能谱分析,对铜蓝和硫砷铜矿的表面性质和分离机理展开研究。通过能带结构、态密度、电荷分布、Mulliken布居分析研究了铜蓝和硫砷铜矿体相和常见解理面的相关性质。发现在费米能级附近,铜蓝和硫砷铜矿体相中S参与所有成键,两种矿物解理面中Cu的活性较强,易于与药剂发生吸附。由于硫砷铜矿的表面更稳定,在矿浆环境中晶体重构时铜蓝和硫砷铜矿的表面性质趋同,导致二者分离难度较高。抑制剂筛选试验结果表明,在使用Ca O调浆至p H=10,有机抑制剂木质素磺酸钙用量为5×10^-5mol/L时,铜蓝与硫砷铜矿浮选分离效果最佳,浮选回收率差异达到26.75%。人工混合矿浮选试验表明在p H=10时,木质素磺酸钙用量为5×10^-5mol/L时,可获得含砷4.98%的低砷铜精矿和10.46%的高砷铜精矿。实际矿石浮选试验表明,使用木质素磺酸钙为抑制剂,结合活性炭脱药优化工艺,可获得含Cu 22.92%,As 2.79%,Cu回收率为27.98%,As回收率为48.81%的高砷铜精矿;及含Cu 20.05%,As 0.87%,Cu回收率为72.02%,As回收率为51.19%的低砷铜精矿,实现了铜蓝和硫砷铜矿的有效分离。接触角测试表明,使用氧化钙调整p H至10,经过5×10^-5mol/L木质素磺酸钙处理后,虽然铜蓝和硫砷铜矿表面的接触角均减小,但铜蓝表面接触角降幅更大;吸附量测试试验进一步表明,木质素磺酸钙的加入能够降低丁铵黑药在铜蓝和硫砷铜矿表面的吸附,且在铜蓝表面的降低程度更大。两个试验结果表明氧化钙和木质素磺酸钙的使用能够增大铜蓝和硫砷铜矿表面疏水性差异。结合红外光谱分析、FESEM-EDS分析和XPS分析可知,在氧化钙调浆环境中,铜蓝和硫砷铜矿表面吸附了一定量的Ca位点,木质素磺酸钙加入后不仅能够以化学方式吸附在矿物表面,并且能够通过-SO₃基团与矿物表面Ca位点发生络合。由于铜蓝表面对Ca和木质素磺酸钙的吸附能力强于硫砷铜矿,这使得铜蓝表面吸附的亲水产物要多于在硫砷铜矿表面所吸附的产物,使得硫砷铜矿可浮性受影响较小,铜蓝受抑制较强,二者能够实现浮选分离。本论文研究丰富了铜精矿降砷的相关理论,为实际生产中铜蓝与硫砷铜矿的分离提供了理论依据和数据支撑。更多还原

【Abstract】 The presence of arsenic in copper concentrate will not only adversely affect the smelting of copper concentrate,but also pollute the environment and cause harm to human health.Covellite and enargite are copper sulfide minerals with similar physicochemical properties,both of which will enter into the copper concentrate during flotation causing the arsenic content in the copper concentrate to exceed the standard.If the separation of these two minerals can be realized,the copper concentrate will be divided into two products:high arsenic concentrate and low arsenic concentrate,which will help to improve the comprehensive valuation factor of copper concentrate and increase the economic benefits of the processing factory.In this thesis,the differences in crystal structures and properties of covellite and enargite were studied.On this basis,single mineral tests were carried out to investigate the effects of common ions and different depressants on the flotation separation of covellite and enargite,and validated in artificial mixed copper-arsenic ore and actual copper concentrate flotation tests.The surface properties and separation mechanism of covellite and enargite were investigated by combining Materials Studio simulations,contact angle measurements,Fourier-transform infrared spectroscopy,scanning electron microscopy and X-ray photoelectron spectroscopy analysis.The relevant properties of covellite and enargite bulk and common cleavage plane were investigated by band structure,density of states,charge distribution,and Mulliken analysis.It was found that near the Fermi energy level,S in the bulk of covellite and enargite is involved in all bonding and very active.Cu is more active at the cleavage surface of covellite and enargite which is easily adsorbed with reagents.The surface properties of the two minerals converge when the crystals are reconstituted in the slurry environment due to the more stable surface of enargite,which lead to a higher difficulty in their separation.The micro-flotation tests results of depressants selection showed that the organic depressant calcium lignosulfonate had the best effect on the flotation separation of covellite and enargite when the pulp was adjusted to p H=10 using calcium oxide.And the difference in flotation recovery of covellite and enargite reached 26.75%when dosage of CLS was 5x10^-5 mol/L.Artificial mixed ore flotation tests showed that a low arsenic copper concentrate containing 4.98%arsenic and a high arsenic copper concentrate containing 10.46%arsenic could be obtained under the same experimental conditions.The actual ore flotation tests showed that the use of calcium lignosulfonate as a depressant,combined with the optimized process of activated carbon stripping,resulted in a high arsenic copper concentrate containing 22.92%Cu,2.79%As,with a Cu recovery of 27.98%and As recovery of 48.81%.And low arsenic copper concentrate contained Cu 20.05%,As 0.87%,Cu recovery of 72.02%and As recovery of 51.19%,achieving the effective separation of covellite and enargite.The contact angle measurements showed that the contact angle on the surface of both covellite and enargite decreased after 5x10^-5 mol/L calcium lignosulfonate treatment using calcium oxide adjusted to p H 10,and the contact angle decreased on the surface of covellite was more obvious.The adsorption test further showed that the addition of calcium lignosulfonate was able to reduce the adsorption of Ammonium dibutyl dithiophosphate（ADD）on the surface of both covellite and enargite,and the reduction on the surface of covellite is higher than that of enargite.The results of both tests indicated that the use of calcium oxide and calcium lignosulfonate could increase the hydrophobicity difference between covellite and enargite surfaces.Combined with FT-IR spectroscopy,FESEM-EDS analysis and XPS analysis,it can be seen that in the calcium oxide slurry environment,covellite and enargite adsorbed a certain amount of Ca sites on the surface,and the addition of calcium lignosulfonate not only adsorbed chemically on the mineral surface,but also complexed with the Ca sites on the mineral surface through the-SO₃ group.Because the adsorption ability of covellite surface to Ca and calcium lignosulfonate was stronger than that of enargite,more hydrophilic products were adsorbed on the surface of covellite than those adsorbed on the surface of enargite,which made the floatability of enargite less affected and covellite more inhibited,and then achieved flotation separation.This thesis enriches the theory of arsenic reduction in copper concentrate and provides theoretical basis and data support for the separation of covellite and enargite in practical production.更多还原