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Method for preparing iron phosphate from calcium-free chromic slag

A calcium-chrome slag-free and iron phosphate-free technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as increased stockpiling of chromium slag, inactive cooperative manufacturers, harsh reaction conditions, etc., and achieve high added value , Process parameters are easy to control, and the effect of easy large-scale production

Inactive Publication Date: 2015-06-24
陕西绿泉环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, whether it is used as an additive for cement production or as a sintering agent for steelmaking, it is necessary to cooperate with relevant manufacturers. Often due to problems such as chromium slag transportation, addition process, and cost, the cooperative manufacturers are not active, and the reduced chromium slag cannot be obtained in time. The amount of chromium slag stockpiled by chromium salt manufacturers is increasing day by day, and the pressure on the environment is increasing day by day.
However, there is no relevant literature report on the conversion of iron contained in chromium slag to higher value-added iron phosphate
Patent application number 201010107049.9 discloses a method for comprehensively utilizing calcium-free chromium slag to directly produce chromium-based alloy steel. In addition, patent application number 201210331157.3 also discloses a method for preparing chromium-containing iron powder by direct reduction of calcium-free chromium slag The method of detoxification and comprehensive utilization of calcium-chromium-free slag disclosed in these two patents has complicated process, harsh reaction conditions and high treatment cost

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  • Method for preparing iron phosphate from calcium-free chromic slag

Examples

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Embodiment 1

[0024] A kind of method of preparing ferric phosphate from calcium-free chromium slag of the present embodiment, its specific steps are as follows:

[0025] (1) Crush 100Kg of calcium-free chromium slag (provided by Hubei Zhenhua Chemical Co., Ltd.) to 320 mesh; soak in 300Kg of water for the first time, stir for 2 hours, and filter; soak in 200Kg of water for the second time, stir for 2 hours hours, filter, combine the secondary alkaline soaking solution, and store for future use.

[0026] (2) Heat the alkaline solution stored in step (1) to 60-70°C, add 4.5Kg of newly prepared 30% (mass percent) sodium sulfide solution, and reduce hexavalent chromium to trivalent chromium precipitation until no Cool until precipitation, filter out the chromium hydroxide precipitate, and keep the filtrate for future use.

[0027] (3) Add 200Kg of water to the calcium-chromium-free slag treated in step (1), and add 60Kg of concentrated sulfuric acid dropwise to make the pH value of the acidif...

Embodiment 2

[0030] A kind of method of preparing ferric phosphate from calcium-free chromium slag of the present embodiment, its specific steps are as follows:

[0031] (1) Crush 100Kg of calcium-free chromium slag (provided by Hubei Zhenhua Chemical Co., Ltd.) to 320 mesh; soak in 500Kg of water for the first time, stir for 2 hours, and filter; soak in 400Kg of water for the second time, stir for 2 hours hour, soak and stir with 200 Kg water for the third time for 2 hours, filter, combine three alkaline soaking liquids, and store for future use.

[0032](2) Heat the alkaline solution stored in step (1) to 60-70°C, add 4.5Kg of newly prepared 30% (mass percent) sodium sulfide solution, and reduce hexavalent chromium to trivalent chromium precipitation until no Cool until precipitation, filter out the chromium hydroxide precipitate, and keep the filtrate for future use.

[0033] (3) For the calcium-free chromium slag treated in step (1), add 200Kg of water and drop in 60Kg of concentrated...

Embodiment 3

[0036] A kind of method of preparing ferric phosphate from calcium-free chromium slag of the present embodiment, its specific steps are as follows:

[0037] (1) Crush 100Kg of calcium-free chromium slag (provided by Hubei Zhenhua Chemical Co., Ltd.) to 250 mesh; soak in 400Kg of water for the first time, stir for 2 hours, and filter; soak in 300Kg of water for the second time, stir for 2 hours Hours, combined two times of alkaline soaking solution, stored for later use.

[0038] (2) Heat the alkaline solution stored in step (1) to 60-70°C, add 4.5Kg of newly prepared 30% (mass percent) sodium sulfide solution, and reduce hexavalent chromium to trivalent chromium precipitation until no Cool until precipitation, filter out the chromium hydroxide precipitate, and keep the filtrate for future use.

[0039] (3) Add 200Kg of water to the calcium-free chromium slag after step (1), drop 200Kg of concentrated sulfuric acid to make the pH value of the acidification solution reach betwe...

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Abstract

The invention relates to a method for preparing iron phosphate from calcium-free chromic slag. The preparation method comprises the following steps: (1) crushing the calcium-free chromic slag and adding water to leach, and then carrying out solid-liquid separation; (2) heating a leached solution obtained by separating, and reducing for detoxifying Cr<6+>; (3) acidifying the separated calcium-free chromic slag by steps and filtering to enable the pH value of a final acidifying solution to be 1-2, collecting and combining the acidifying solution, adjusting the pH value to 3-4 to enable iron ions and aluminum ions to generate red sediment to be separated out, filtering and adjusting the pH value of a filtrate to 9-10, and heating to reduce and detoxify the Cr<6+> in the filtrate; (4) gradually adding the red sediment into a diluted phosphoric acid and dissolving, keeping the pH value of the solution to be 3-5, after completely converting the red sediment into white sediment, standing and filtering to obtain an iron phosphate wet material, and drying by microwaves at a constant temperature of 90 DEG C to obtain iron phosphate powder. The method is simple in technological process and low in industrial cost; the calcium-free chromic slag can be completely detoxified and a new way for comprehensively utilizing the calcium-free chromic slag is explored.

Description

technical field [0001] The invention relates to the technical field of solid waste treatment and resource utilization, more specifically, the invention relates to a method for preparing inorganic iron phosphate from calcium-chromium-free slag. Background technique [0002] Chromium salt is an important inorganic salt product. In recent years, under the guidance of relevant government departments, the chromium salt manufacturers in my country have undergone technological transformation, and most of them adopt calcium-free roasting process. Although the amount of chromium slag produced is reduced compared with the calcium roasting process, the chromium slag produced still contains hexavalent chromium. Because Cr(Ⅵ) has excessive water solubility and is highly toxic, it is internationally recognized as the 47 most dangerous wastes. One of them is listed as a national hazardous waste. The main chemical components and contents of the chromium slag discharged during the productio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/37C01G37/00A62D3/37A62D101/43
Inventor 刘瑞华
Owner 陕西绿泉环保科技有限公司