阅读说明：本技术 一种粗硒提纯方法 (Crude selenium purification method ) 是由 徐宝强 罗欢 杨斌 查国正 蒋文龙 杨佳 刘大春 王飞 李一夫 田阳 熊恒 孔 于 2019-11-01 设计创作，主要内容包括：本发明公开一种粗硒提纯方法,向粗硒渣中加入调控剂进行调浆至pH值为6.5~7,调控剂对粗硒渣的氧化和调浆同时进行,缩短工艺周期、降低成本,然后抽滤,得到粗硒粉,滤饼再经过真空蒸馏后冷凝得到精硒；本发明通过向粗硒渣中加入调控剂,调控剂为氧化剂和碱的混合溶液,混合溶液与粗硒渣中的杂质元素发生氧化反应,使杂质组元的赋存状态发生改变的同时进行调浆；利用赋存状态改变的杂质氧化物与硒在真空条件下性质的差异,通过真空蒸馏使硒与杂质元素高效分离,降低硒中杂质元素的含量,得到纯度高的硒产品。(The invention discloses a crude selenium purification method, wherein a regulating agent is added into crude selenium slag for size mixing until the pH value is 6.5-7, the regulating agent is used for oxidizing and size mixing the crude selenium slag at the same time, the process period is shortened, the cost is reduced, then, the crude selenium powder is obtained by suction filtration, and the filter cake is condensed after vacuum distillation to obtain refined selenium; adding a regulating agent into the crude selenium slag, wherein the regulating agent is a mixed solution of an oxidant and alkali, and the mixed solution and impurity elements in the crude selenium slag are subjected to oxidation reaction, so that the occurrence state of impurity elements is changed and the pulp is mixed; by utilizing the property difference of the impurity oxide with changed occurrence state and the selenium under the vacuum condition, the selenium and the impurity element are efficiently separated through vacuum distillation, the content of the impurity element in the selenium is reduced, and the selenium product with high purity is obtained.)

1. A method for purifying crude selenium is characterized by comprising the following steps:

adding a regulating agent into the crude selenium slag, mixing the slurry until the pH value is 6.5-7, then carrying out suction filtration, and condensing a filter cake after vacuum distillation to obtain refined selenium.

2. The crude selenium purification method according to claim 1, wherein the mass fraction of Se in the crude selenium slag is 85% to 90%, the mass fraction of Te is 1% to 4%, the mass fraction of Cu is 1% to 2%, the mass fraction of Pb is 1% to 2%, and the balance is unavoidable impurities.

3. The method for purifying crude selenium according to claim 1, wherein the controlling agent is H with a volume ratio of 1:1 to 1:3₂O₂Solution and Na₂CO₃The mixed solution is formed by mixing solutions or H with the volume ratio of 1: 1-1: 2₂O₂Mixing the solution with NaOH solution to obtain mixed solution; wherein H₂O₂The mass concentration of the solution is 15 percent, and Na is added₂CO₃The concentration of the solution is 0.5-1 mol/L, and the concentration of the NaOH solution is 0.5-1 mol/L.

4. The method for purifying the crude selenium according to claim 1, wherein the temperature of the vacuum distillation is 250 ℃ to 280 ℃, the heat preservation time is 1 to 2 hours, and the pressure is 10Pa to 200 Pa.

Technical Field

The invention relates to the field of purification and preparation of rare metals, in particular to a crude selenium purification method.

Technical Field

Selenium, as a rare and dispersive metal, has become a key material for supporting the development of new products of high-tech development and materials (medicines, agriculture and foods). More than 90% of the selenium in industry is produced from the comprehensive recovery and utilization process of the copper anode slime. Copper anode mud is treated by sulfuration roasting, Se is SeO₂The gas is volatilized to remove selenium and then is dissolved in water to obtain SeO₃ ^2-Solution, then SO coated₂Reducing and precipitating to obtain crude selenium powder; or leaching the copper anode mud by adopting sodium hypochlorite solution to obtain SeO₃ ^2-Solution, then SO coated₂Reducing and precipitating to obtain crude selenium powder. The crude selenium powder generally contains more than 65 percent of selenium, more than 20 percent of water, impurity elements such as tellurium, lead, iron, sulfur, rare and precious metal elements and the like, and needs to be purified to produce industrial selenium products. CN1636867 discloses a process for extracting selenium by vacuum smelting, in which a material and a binder are uniformly mixed, dried, granulated, dried to obtain a mixed material, and vacuum distilled to obtain a selenium product, but the purity of the obtained product is not higher than 98%. CN 109336068 discloses a method for removing tellurium from selenium slag to purify selenium, wherein an oxidant is added into crude selenium slag, and the oxidant and tellurium in the crude selenium slag are subjected to oxidation reaction and then are subjected to heating treatment, so that the form of tellurium is changed; tellurium is separated from selenium by vacuum distillation by utilizing the property difference between tellurium oxide with changed form and selenium in vacuum stateRemoving and reducing the tellurium content in the selenium to obtain a selenium product with the purity of more than 99.9 percent. Only the influence of tellurium on the purification of crude selenium is studied, and other impurities are not involved; european rains and the like oxidize selenium in selenium-containing waste into an ionic state by using hydrogen peroxide under a strong acid condition, then add a proper amount of sodium chloride and ammonia water in the reaction process, obtain selenium-containing filtrate through solid-liquid separation, and reduce the selenium-containing filtrate by using hydrazine hydrate to obtain a selenium simple substance, wherein the purity can only reach more than 90%.

Disclosure of Invention

In view of the above, the invention provides a method for purifying crude selenium, which is simple and rapid to operate, does not generate toxic and harmful substances, and has high purity of the obtained refined selenium.

The technical scheme of the invention is as follows:

a method for purifying crude selenium comprises the following steps:

adding a regulating agent into the crude selenium slag for size mixing until the pH value is 6.5-7, oxidizing the crude selenium slag by the regulating agent and carrying out size mixing simultaneously, shortening the process period, reducing the cost, then carrying out suction filtration to obtain filter cake crude selenium powder, and condensing the filter cake crude selenium powder after vacuum distillation to obtain high-purity refined selenium.

The mass fraction of Se in the crude selenium slag is 85-90%, the mass fraction of Te is 1-4%, the mass fraction of Cu is 1-2%, the mass fraction of Pb is 1-2%, and the balance is unavoidable impurities.

The regulating agent is H with the volume ratio of 1: 1-1: 3₂O₂Solution and Na₂CO₃The mixed solution is formed by mixing solutions or H with the volume ratio of 1: 1-1: 2₂O₂Mixing the solution with NaOH solution to obtain mixed solution; wherein H₂O₂The mass concentration of the solution is 15 percent, and Na is added₂CO₃The concentration of the solution is 0.5-1 mol/L, and the concentration of the NaOH solution is 0.5-1 mol/L.

The temperature of the vacuum distillation is 250-280 ℃, the heat preservation time is 1-2 h, and the pressure is 10-200 Pa.

The invention has the beneficial effects that: adding a regulating agent into the crude selenium slag, wherein the regulating agent is a mixed solution of an oxidant and alkali, and the mixed solution and impurity elements in the crude selenium slag are subjected to oxidation reaction, so that the occurrence state of impurity elements is changed and the pulp is mixed; by utilizing the property difference of the impurity oxide with changed occurrence state and the selenium under the vacuum condition, the selenium and the impurity element are efficiently separated through vacuum distillation, the content of the impurity element in the selenium is reduced, and the selenium product with high purity is obtained.

Detailed Description

The invention provides a new process for purifying crude selenium, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.