High-stability magnesium-ferrous composite flocculating agent and production technology thereof

Abstract

The invention provides a production technology of a high-stability magnesium-ferrous composite flocculating agent. The flocculating agent comprises 100 weight parts of brine, 5 to 20 weight parts of industrial grade ferrous sulfate heptahydrate, and 0.2 to 5 weight parts of hydrochloric acid. The production technology comprises the following steps of: putting the industrial grade ferrous sulfate heptahydrate into an anticorrosive tank, and adding the industrial hydrochloric acid which is diluted by 2 to 5 times through the brine for complexing and curing; slowly adding the brine into the cured solution with stirring; regulating the pH value of the solution to be between 1 and 3 by using a salt or a weakly alkaline substance; putting micro iron powder which attracts a magnet and is used as a stabilizer into the solution, performing reduction reaction, and quickly regulating the proportion of divalent iron to trivalent iron; and sealing and preserving the solution. The flocculating agent is high in stability, and can overcome the defects that the solution is foamed and overflows a reactor when the iron powder is added for oxidation resistance and the residue blocks a conveying pipeline in the prior art.

Description

【Technical field】 [0001] The invention relates to a high-stability magnesium-ferrous composite flocculant and a production process thereof. 【Background technique】 [0002] Flocculant is a chemical used for sewage purification. Common flocculants in industry include aluminum salt flocculants, which are suitable for treating sewage with a pH of 5-9, poor decolorization ability, poor ability to remove heavy metals, and high biological toxicity; iron salt flocculants are suitable for treatment PH3-11 sewage has poor decolorization ability and effluent chroma; ferrous salt flocculant is suitable for treating PH8-12 sewage and effluent chroma is very poor; polyacrylamide flocculant is basically suitable for the treatment of all sewage , but it should be used in conjunction with flocculants; aluminum-iron, aluminum-ferrous composite flocculants, etc., and their preparation processes are relatively mature. There are other flocculants, such as biological flocculants, silicic acid fl...

AI Technical Summary

Problems solved by technology

However, the unsolvable problems of this process are: serious foaming of the drug solution during production, more precipitation and hardening of basic ferric sulfate during drug storage, frequent repairs and cleaning of drug storage tanks and drug pumping equipment are required

[0011] The magnesium ferrous flocculant of brine + ferrous ferrous has not yet been commercially used in large quantities. The reason is that: because industrial ferrous sulfate is easily oxidized into insoluble basic ferric sulfate during storage, the medicine directly prepared with water is turbid and has a large number of fine particles. Precipitated yellow-green ferrous sulfate aqueous solution, it is difficult to dissolve these precipitates by conventional methods of adding sulfuric acid to increase acidity

When using brine as a solvent and adding ferrous sulfate to dissolve, a large amount of green precipitates will also be formed. Even if sulfuric acid is added to dissolve, only a brownish-yellow liquid with a large number of turbid particles will be formed. The speed is very fast: Ferrous iron is easily oxidized by oxygen in the air in the brine, and the ferric iron, the oxidation product, quickly reacts with sodium sulfate in the brine and transforms into sodium jaronite precipitation, which leads to the failure of the magnesium-iron composite flocculant for a long time if it is not sealed. Preservation and precipitation are likely to cause blockage of the chemical delivery pipeline; if ferrous chloride is used instead of ferrous sulfate, the amount of precipitation in the chemical can be reduced, but the cost will increase significantly. The use of various pickling wastewater can achieve no precipitation, but heavy metals cannot be guaranteed Therefore, it is difficult to commercialize and store a large amount of magnesium and ferrous flocculants after configuration