Determination of Ni, Co, Mg, Al and Fe in Laterite Nickel Ore by Inductively Coupled Plasma-Atomic Emission Spectrometry
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摘要: 红土镍矿分析没有统一的国家标准,行业标准于2013年初刚制定,其应用处于起步阶段,且行业标准中红土镍矿各元素主要采用化学分析法测定,操作程序繁琐耗时,工作量大,分析效率低。本文建立了电感耦合等离子体发射光谱测定红土镍矿中镍、钴、镁、铝和铁含量的方法。红土镍矿样采用王水溶解,加入氢氟酸和高氯酸,加热至高氯酸烟冒尽,再用盐酸溶解盐类,对消解后溶液中镍、钴、镁、铝和铁等目标元素选择了合适的分析谱线消除干扰。方法检出限镍为2.98 μg/g,钴为1.60 μg/g,镁为1.68 μg/g,铝为3.79 μg/g,铁为9.52 μg/g;方法精密度(RSD,n=11)为1.5%~2.2%;加标回收率为96.0%~102.5%。国家标准物质分析的测定值与标准值和外检值吻合较好。该方法简便快速,单元素不需分别处理,提高了分析效率,能够满足红土镍矿冶炼生产和地质探矿样品测定及时性的要求。Abstract: There is no uniform national assay standard for nickel laterite, and the industry standard has only recently been established in early 2013. The major elements of nickel laterite in the industry standard are tested by chemical analysis with a time-consuming, heavy workload and low efficiency which is unable to meet requirements in laterite nickel ore smelting production. A new analytical method has been established to determine Ni, Co, Mg, Al and Fe in laterite nickel ore by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The samples were digested by aqua regia, hydrofluoric acid and perchloric acid, and heated until the perchloric acid fume was eliminated, then dissolved by hydrochloric acid. The optimum analytical spectral lines were chosen after studying the spectral interferences for the selected elements to eliminate interference. Experimental results show that the detection limits of the method are Ni 2.98 μg/g, Co 1.60 μg/g, Mg 1.68 μg/g, Al 3.79 μg/g and Fe 9.52 μg/g, , respectively. The relative standard deviations (RSD, n=11) are 1.5%-2.2%. The recovery rates of Ni,Co, Mg, Al and Fe are 96.0%-102.5%. The method was verified by the standard sample, and the measured value agrees well with the standard value. The method is simple and fast and can be widely used to guide the exploration and smelting process for laterite nickel ore.
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Key words:
- laterite nickel ore /
- nickel /
- cobalt /
- magnesium /
- aluminum /
- iron /
- acid dissolution /
- Inductively Coupled Plasma-Atomic Emission Spectrometry
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表 1 仪器工作条件
Table 1. Working parameters of the instrument
工作参数 设定条件 射频功率 1200 W 等离子气流量 15.00 L/min 辅助气流量 1.50 L/min 雾室压力 200 kPa 冲洗时间 10 s 观测高度 10 mm 泵速 10 r/min 重复次数 3 表 2 分析谱线及测定范围
Table 2. Analytical spectral lines and measurement range
元素 波长
λ/nm测定范围
w/%Ni 231.604 0.10~2.00 Co 228.615 0.05~0.30 Mg 280.270 0.10~10.00 Al 394.401 0.10~10.00 Fe 238.204 10.00~50.00 表 3 混合标准溶液
Table 3. Mixed standard solutions
元素 ρ/(μg·mL-1) STD 0 STD 1 STD 2 STD 3 STD 4 STD 5 STD 6 Ni 0 1 5 10 15 20 0 Co 0 0.5 1.0 1.5 2.0 2.5 3.0 Mg 0 1 5 10 30 60 100 Al 0 1 5 10 30 60 100 Fe 0 100 200 300 400 500 0 表 4 标准曲线线性相关系数和方法检出限
Table 4. Relative coefficients of calibration curve and the detection limits for the elements
元素 标准曲线的相关系数 检出限/(μg·g-1) Ni 0.99998 2.98 Co 0.99984 1.60 Mg 0.99991 1.68 Al 0.99853 3.79 Fe 0.99966 9.52 表 5 方法准确度试验
Table 5. Accuracy tests of the method
w/% 元素 本实验室 北矿院外检 本法
测定值标准值 相对
误差/%本法
测定值标准值 相对
误差/%Ni 1.96 1.97 -0.51 1.39 1.38 0.72 Co 0.071 0.069 2.90 0.10 0.10 0 Mg - - - 1.16 1.20 -3.33 Al - - - 2.34 2.34 0 Fe 23.29 23.40 -0.47 46.63 47.76 -2.37 注:北京矿冶研究总院测试研究所采用的分析方法为GB/T 6730.5—2007(元素Fe),YS/T 820.20—2012(元素Al),YS/T 820.22—2012(元素Mg),GB/T 14353.5,6—2010(元素Ni、Co)。 表 6 方法精密度试验
Table 6. Precision tests of the method
元素 w/% RSD/% 本法分次测定值 平均值 Ni 1.010 1.020 1.020 1.023 1.055 1.045 1.050 1.031 1.033 1.5 1.029 1.035 1.049 Co 0.088 0.092 0.087 0.089 0.090 0.093 0.091 0.093 0.091 2.2 0.089 0.092 0.093 Mg 1.321 1.335 1.336 1.343 1.369 1.372 1.393 1.349 1.352 1.6 1.340 1.335 1.377 Al 3.384 3.430 3.441 3.461 3.612 3.618 3.541 3.575 3.502 2.2 3.490 3.474 3.492 Fe 44.512 45.083 45.074 45.481 46.552 46.364 46.621 46.566 45.739 1.5 45.571 45.601 45.699 表 7 方法回收率试验
Table 7. Recovery tests of the method
元素 加入量
m/μgw/% 回收率/% 加标前浓度 加标后浓度 Ni 1000 1.053 2.038 98.5 Co 100 0.090 0.192 102.0 Mg 1000 0.783 1.808 102.5 Al 2000 2.317 4.236 96.0 Fe 44500 44.192 89.283 101.3 -
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