含镍料液中硝酸铵和硝酸镍的分离研究

以分离并回收含镍料液中的硝酸铵和硝酸镍为目的，验证了纳滤和硫化铵沉淀联用技术的可行性，并通过考察纳滤浓水侧压力、纳滤级数、硫化铵沉淀pH值等的影响，获得适宜的工艺路线为：两级纳滤+KLNi-01离子交换除镍+硫化铵沉镍+硝酸溶解回收硝酸镍。操作参数如下：纳滤进水pH=6、浓水侧压力0.8 MPa,经两级纳滤后，产水镍含量降至0.181 g/L,再经KLNi-01树脂吸附后，镍含量降至0.002 mg/L;纳滤浓水在初始pH=6、硫化铵溶液加入量36 mL/L条件下沉镍，此时出水镍含量4.7 mg/L,无硫化物检出；使用硝酸溶解硫化镍沉淀，可获得浓度为258.40 g/L的硝酸镍溶液。物料衡算可得：处理1 m³含镍料液，获得产水0.3 m³,消耗20%～26%的硫化铵溶液25.20 L,消耗浓硝酸37.22 L,消耗水体积109.05 L,可获得258.40 g/L的硝酸镍溶液192.93 L。

Separation of Ammonium Nitrate and Nickel Nitrate from Nickel-Containing Feed Solution

A technique of nanofiltration combined with ammonium sulfide precipitation was verified for its feasibility of separating and recovering ammonium nitrate and nickel nitrate from nickel-containing feed solution. Based on investigating the effects of pressure on the side of concentrate stream in nanofiltration, stages of nanofiltration and pH value of ammonium sulfide precipitate, an appropriate route was determined, including two-stage nanofiltration, KLNi-01 ion exchange to remove nickel, nickel precipitation with ammonium sulfide, and dissolution with nitric acid to recover nickel nitrate. The feed stream with pH of 6 was subjected to a two-stage nanofiltration, with pressure of 0.8 MPa on the side of concentrate stream. The obtained permeate stream with nickel content decreased to 0.181 g/L was adsorbed with KLNi-01 resin, leading to the nickel content therein further reduced to 0.002 mg/L. Then, 36 mL/L ammonium sulfide solution was added into the concentrate stream with an initial pH of 6 for nickel precipitation. The generated solution had nickel content of 4.7 mg/L, and no sulfide was detected, while the obtained precipitate of nickel sulfide was then dissolved with nitric acid, and the nickel nitrate solution was obtained with concentration of 258.40 g/L. The material balance calculation shows that treatment of 1 m3 of nickel-containing feed stream can generate 0.3 m3 permeate, and 192.93 L of nickel nitrate solution with concentration of 258.40 g/L can be generated with the consumption of 25.20 L of ammonium sulfide solution with concentration of 20%-26%, 37.22 L of concentrated nitric acid and 109.05 L of water.