CN101717331B

CN101717331B - Method for preparing iron oxalate

Info

Publication number: CN101717331B
Application number: CN 200910310496
Authority: CN
Inventors: 陈祝春; 刘森林; 李哲; 程世华; 黄家旭; 陆平; 李良; 罗建林
Original assignee: Pangang Group Steel Vanadium and Titanium Co Ltd; Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Current assignee: Pangang Group Steel Vanadium and Titanium Co Ltd; Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
Priority date: 2009-11-26
Filing date: 2009-11-26
Publication date: 2013-04-17
Anticipated expiration: 2029-11-26
Also published as: CN101717331A

Abstract

本发明涉及制备草酸亚铁的方法，属于化工领域。本发明所解决的技术问题是提供了一种制备草酸亚铁的方法，该方法可以循环利用钛精矿制取钛白时产生的副产物绿矾。本发明制备草酸亚铁的方法，是以硫酸法制取钛白粉的副产物绿矾为原料，具体步骤如下：a、绿矾加水溶解，得到硫酸亚铁溶液，用氨水调节pH值为5.6～6.5，过滤；b、滤液用P₂O₄萃取，分离得到有机相和水相；c、水相中加入含F的溶液以沉淀Mg²⁺，过滤，滤液中加入草酸溶液，过滤，即得草酸亚铁结晶。本发明方法不仅解决了绿矾堆放的问题，还提高了绿矾的经济利用价值，为硫酸法制取钛白粉的副产物绿矾的处理提供了一种新的选择，具有广阔的应用前景。The invention relates to a method for preparing ferrous oxalate, which belongs to the field of chemical industry. The technical problem solved by the present invention is to provide a method for preparing ferrous oxalate, which can recycle the by-product greenite produced when titanium concentrate is prepared from titanium dioxide. The method for preparing ferrous oxalate of the present invention is to take the by-product green vitriol of titanium dioxide produced by the sulfuric acid method as raw material, and the concrete steps are as follows: a, green vitriol is dissolved in water to obtain ferrous sulfate solution, and the pH value is adjusted to 5.6 to 6.5 with ammonia water , filtered; b, the filtrate was extracted with P ₂ O ₄ , separated to obtain an organic phase and an aqueous phase; c, a solution containing F was added to the aqueous phase to precipitate Mg ²⁺ , filtered, and an oxalic acid solution was added to the filtrate, and filtered to obtain oxalic acid Ferrous crystals. The method of the invention not only solves the problem of the green vitriol stacking, but also improves the economic utilization value of the green vitriol, provides a new option for the treatment of the by-product green vitriol produced by the sulfuric acid method, and has broad application prospects.

Description

The method for preparing Ferrox

Technical field

The present invention relates to prepare the method for Ferrox, belong to chemical field.

Background technology

Take ilmenite concentrate as raw material, when adopting the sulfuric acid process preparing titanium dioxide, the iron in the ilmenite concentrate can dissolve in a large number, generates ferrous sulfate, and when separating with titanium liquid through freezing iron removal step, crystallization goes out FeSO ₄7H ₂O (green vitriol).The TiO of the ilmenite concentrate of China's Panzhihua Region ₂Content is about 47%, and when adopting this kind ilmenite concentrate to produce titanium white, 1 ton of titanium dioxide of every production obtains about 3.5 tons of by product green vitriols.Along with the expansion of Producing Titanium Dioxide ability, the green vitriol problem has become the important factor that the restriction sulfate process titanium dioxide is produced.Because the green vitriol purposes is narrower, be difficult to mass disposal, and green vitriol has stronger solubility, can't air storage store, seriously restricted the Sustainable development of titanium white enterprise.For ferrous sulfate comprehensive utilization, domesticly done a large amount of research, but owing to use quantitative limitation, the present still progress of achieving no breakthrough property.

Ferrox can be widely used in the tinting material of coating, dyestuff, pottery, glassware etc. as a kind of industrial chemicals, and the producing of novel battery material, sensitive materials.Ferrox is just causing people's extensive concern as the raw material of synthesis of anode material of lithium-ion battery LiFePO 4.

Ferrox FeC ₂O ₄2H ₂The common preparation method of O is to synthesize with ferrous ammonium sulphate and oxalic acid.Recent years, report and produce Ferrox with desulfurization slag and rhombohedral iron ore.No matter be adopt slag or ore deposit to produce Ferrox all need be through broken essence, fine grinding, acidleach, removal of impurities, the operation such as synthetic, operation is complexity comparatively, and it is higher to produce cost.

Summary of the invention

Technical problem to be solved by this invention provides a kind of method for preparing Ferrox, the by product green vitriol that the method produces when can the recycle ilmenite concentrate producing titanium white.

The present invention prepares Ferrox FeC ₂O ₄2H ₂The method of O, be by product green vitriol take the sulfuric acid process preparing titanium dioxide as raw material, concrete steps are as follows:

A, green vitriol are dissolved in water, and obtain copperas solution, and regulating the pH value with ammoniacal liquor is 5.6～6.5, filter;

B, filtrate extract with P2O4, separate to obtain organic phase and water;

C, aqueous phase adding contain the solution of F-with precipitation Mg ²⁺, filter, add oxalic acid solution in the filtrate, filter, namely get the Ferrox crystallization.

Further, the above-mentioned method for preparing Ferrox, in the described copperas solution of its a step

Fe ²⁺Concentration is preferably 75～85g/L.Fe ²⁺Concentration is excessively low, and then the oxalic acid utilization ratio reduces, Fe ²⁺Excessive concentration, then crystallization appears in copperas solution easily.

Wherein, the above-mentioned method for preparing Ferrox precipitates as far as possible fully in order to make the impurity such as calcium, aluminium, titanium, and its a step is regulated the pH value with ammoniacal liquor and is preferably 6.

Wherein, the above-mentioned method for preparing Ferrox also adds No. 260 kerosene as thinner during its b step extraction, and wherein, the volume ratio of P2O4 and No. 260 kerosene is 2: 2.5～3.5.Further, better in order to make effect of extracting, comparing during extraction is preferably: O/A=1.4～1.6: 1, i.e. the volume sum of P2O4 and No. 260 kerosene: the volume of b step filtrate=1.4～1.6: 1.

Wherein, above-mentioned c step is at precipitation Mg ²⁺The time, the F of adding and the Mg of aqueous phase ²⁺Mol ratio be preferably 2.08～2.12: 1 (most preferably 2.1: 1).In order to precipitate as much as possible fully, need to add slightly excessive F, if but the F adding is too much, then can lose the ferrous iron in the solution.

Further, in order as much as possible ferrous sulfate to be converted into Ferrox fully, above-mentioned c step is at precipitation Mg ²⁺Add excessive supersaturation oxalic acid solution in the rear filtration gained filtrate, filter, namely get the Ferrox crystallization.Can the Ferrox crystallization whether continue to produce to judge whether oxalic acid is excessive when adding oxalic acid solution, also can be by calculating Fe ²⁺Content is determined the add-on of oxalic acid.Wherein, above-mentioned supersaturation oxalic acid solution is to add excessive oxalic acid preparation in 92～97 ℃ the deionized water to get.

Further, in order to obtain the higher Ferrox of purity, the crystallization of above-mentioned c step gained Ferrox is also through 92～97 ℃ deionized water wash, oven dry and pulverization process step below 100 ℃.

Further, the solution of the described F of containing of above-mentioned c step is preferably NH ₄F solution.Add NH ₄F solution can be so that the washing of Ferrox crystallization reduces the washing difficulty.

Further, in order to save production cost, avoid the wasting of resources, the separating obtained organic phase of above-mentioned b step is also stripped with the sulphuric acid soln of 2～3mol/L, makes organic phase regeneration, for recycling; Wherein, being in a ratio of during reextraction: O/A=9～11: 1.

Because contain more foreign metal ion in the by product green vitriol of sulfuric acid process preparing titanium dioxide, as: Mg ²⁺, Al ³⁺Deng, so can not directly adopt oxalic acid and ferrous sulfate reaction preparation Ferrox, need to remove first impurity.The inventive method removal of impurity effect is better, and prepared Ferrox purity can be up to more than 98%.Because adopting the by product green vitriol of sulfuric acid process preparing titanium dioxide is raw material, raw materials cost is lower, not only solved the reluctant problem of green vitriol, also improved the economic use value of green vitriol, for the processing of the by product green vitriol of sulfuric acid process preparing titanium dioxide provides a kind of new selection, have broad application prospects.

Embodiment

Below in conjunction with embodiment the specific embodiment of the present invention is further described, does not therefore limit the present invention among the described scope of embodiments.

Embodiment adopts the inventive method to prepare Ferrox

1,500 gram green vitriols (by product of sulfuric acid process preparing titanium dioxide) is dissolved in the 800ml boiling water, stirring and dissolving, in situation about stirring, slowly add 1: 1 (V/V) ammoniacal liquor (be commercially available strong aqua prepared in by volume 1: 1 with water), the pH value of regulator solution is 6, filter filtrate for later use;

2, solvent extraction

2.1 extraction: P2O4 and No. 260 kerosene were mixed with organic phase in 2: 3 by volume, and organic phase is mixed with the filtrate 1.5: 1 by volume (being O/A=1.5/1) of step 1, concussion 5min, and concussion progression is 3 grades.Separate and obtain organic phase and water.

2.2 strip: organic phase and concentration are the H of 2mol/L ₂SO ₄Solution 10: 1 by volume (being O/A=10/1) mixes, concussion 10min, and concussion progression is 2 grades.Make organic phase regeneration, for recycling.

3, step 2 extraction gained water stirs also the slowly NH of adding 20% ₄F solution, precipitation Mg ²⁺, NH ₄F and Mg ²⁺Mol ratio be 2.1: 1, filter; Filtrate slowly adds supersaturation oxalic acid solution (95 ℃), obtain the Ferrox crystallization, when not having new crystallization to generate, stop to add oxalic acid solution, filter, obtain the Ferrox crystallization, with 95 ℃ deionized water wash Ferrox crystallization, the Ferrox crystallization after the washing shatters after the cooling in 90 ℃ of bakings 2 hours, inspection by sampling, packing obtain the Ferrox product.The quality of gained Ferrox product sees Table 1, and this Ferrox product 100% is by 400 mesh sieves, and the content of Ferrox is 98.42%.

Table 1 Ferrox quality product

Test event	Content (wt%)
		Al	＜0.01
Si	＜0.01
		Ca	＜0.01
Ti	＜0.01
		V	＜0.01
Na	＜0.05
		Mg	＜0.05
K	＜0.05
		SO4 ^2-	＜0.05
Mn	0.075
		H ₂O	0.35
Fe ²⁺	30.62

Claims

1. prepare the method for ferrous oxalate, it is characterized in that: get the by-product green vitriol of titanium dioxide with sulfuric acid method as raw material, concrete steps are as follows:

a, green vitriol is dissolved in water to obtain a ferrous sulfate solution, and the pH value is adjusted to 5.6 to 6.5 with ammonia water, and filtered;

b, the filtrate is extracted with di-(2-ethylhexyl) phosphate, and separated to obtain an organic phase and an aqueous phase;

c. Add F ^- containing solution to the water phase to precipitate Mg ²⁺ , filter, add oxalic acid solution to the filtrate, and filter to obtain ferrous oxalate crystals.

2. the method for preparing ferrous oxalate according to claim 1 is characterized in that: in the ferrous sulfate solution described in a step, Fe ^{Concentration} is 75～85g/L.

3. the method for preparing ferrous oxalate according to claim 2 is characterized in that: a step adjusts pH value to 6 with ammoniacal liquor.

4. The method for preparing ferrous oxalate according to any one of claims 1 to 3, characterized in that: No. 260 kerosene is also added as a diluent during the extraction in step b, wherein di-(2-ethylhexyl) phosphoric acid The volume ratio of ester to No. 260 kerosene is 2:2.5-3.5.

5. the method for preparing ferrous oxalate according to claim 4, is characterized in that: the ratio during b step extraction: organic phase/water phase=1.4～1.6:1.

6. the method for preparing ferrous oxalate according to claim 1 is characterized in that: the F that c step adds ^- and the Mg in aqueous phase The mol ratio of ²⁺ is 2.08～2.12:1.

7. the method for preparing ferrous oxalate according to claim 1 is characterized in that: c step precipitation Mg ^After , filter, add oxalic acid solution in the gained filtrate, filter, obtain ferrous oxalate crystallization; Wherein, the The oxalic acid solution is added by adding excess supersaturated oxalic acid solution, and the supersaturated oxalic acid solution is prepared by adding excess oxalic acid to deionized water at 92-97°C.

8. The method for preparing ferrous oxalate according to claim 7, characterized in that: the ferrous oxalate crystals obtained in step c also undergo the steps of washing with deionized water at 92 to 97°C, drying below 100°C and pulverizing.

9. the method for preparing ferrous oxalate according to claim 1 is characterized in that: the solution containing ^F described in c step is NH ₄ F solution.

10. the method for preparing ferrous oxalate according to claim 1 is characterized in that: b step separation gained organic phase back-extracts with the sulfuric acid solution of 2～3mol/L, makes organic phase regeneration, for recycling; Wherein, The ratio during back extraction is: organic phase/water phase=9～11:1.