Method for producing poly silicate aluminium ferric flocculating agent by utilizing coal gangue

Abstract

The invention relates to the inorganic macromolecule flocculating agent technical field, in particular to a method for producing poly silicate aluminium ferric flocculating agent by utilizing coal gangue. The method includes the following steps: firstly coal gangue is smashed, roasted and mixed with hydrochloric acid by solid-liquid volume ratio of 1:4-6, reaction is carried out, then the obtained reaction liquid is filtered, the obtained residue is for spare use, and the pH value of the obtained filtrate is regulated to be 3-3.5, thus obtaining the poly aluminium ferric solution; then the obtained residue and sodium hydroxide are mixed for reaction by mass ratio of 2-4:1, and the filtrate obtained by filtration of reaction liquid is sodium silicate solution namely; the prepared sodium silicate solution is added with acid for carrying out activation treatment; then the prepared poly aluminium ferric solution and the activated sodium silicate solution are mixed for reaction by mass ratio of 1:1, thus obtaining the poly silicate aluminium ferric flocculating agent. The invention adopts coal gangue as raw material, cost is low, and meanwhile the poly silicate aluminium ferric flocculating agent prepared by the invention has better stability and flocculation effect.

Description

technical field [0001] The invention relates to the technical field of inorganic polymer flocculants, in particular to a method for producing polyaluminum iron silicate flocculants by using coal gangue. Background technique [0002] In recent years, my country's economy and society have developed rapidly, people's living standards have continued to improve, and water consumption and wastewater discharge have increased dramatically. However, my country's available water resources are very limited, which requires effective purification and recycling of discharged wastewater. At present, the commonly used inorganic flocculants are aluminum-based and iron-based. Polyaluminum chloride (PAC) and polyferric sulfate (PFS) are typical representatives of aluminum-based and iron-based flocculants respectively. There are differences between the two. flocculation properties. [0003] For the treatment of domestic sewage and industrial wastewater, polyaluminum chloride (PAC) has the advant...

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Problems solved by technology

[0003] For the treatment of domestic sewage and industrial wastewater, polyaluminum chloride (PAC) has the advantages of good coagulation performance, large flocs, less dosage, fast precipitation, and wide application range; and it has high chemical oxygen demand for treatment. For papermaking wastewater, printing and dyeing wastewater, etc., the amount (COD), chroma and pH value, the decolorization rate is low, and the application is limited; the biggest disadvantage of PAC is that the residual aluminum ion content in the treated wastewater is relatively high. Excessive intake of aluminum in the human body can lead to Alzheimer's disease, which directly limits the application of PAC in purifying drinking water.

[0004] Polyferric sulfate (PFS) has a good effect in treating fluorine-containing wastewater, high-fluorine drinking water, and heavy metal-containing wastewater. The iron ion content in the treated water is high, which makes the water color, so the application range of PFS is limited

[0005] Therefore, the traditional flocculants cannot meet the existing wastewater treatment process. Therefore, it is necessary to develop green flocculants that are compound, high-performance, multi-functional, low-toxic and pollution-free. Among them, polyaluminum iron silicate is a new type of composite inorganic polymer flocculation agent. It not only overcomes the sensitivity of aluminum salt flocculants to pH and the large amount of residual aluminum, but also overcomes the shortcomings of iron salt flocculants with residual color in the effluent. It not only has the functions of adsorption bridging and electrical neutralization, but also molecular polymerization High degree, multi-component synergy, more superior stability and water purification effect, can be widely used in various types of wastewater treatment, at the same time, because the treated water does not contain aluminum and other harmful components, thus eliminating the harmful effects on the human body There are two types of traditional methods for producing polyaluminum-iron silicate flocculants, one is prepared by introducing polyaluminum and iron into polysilicate, and the other is by introducing polysilicate into polyaluminum and iron These methods all use ready-made chemical raw materials for production, and the cost is high. At the same time, the flocculation effect and stability of the polyaluminum iron silicate flocculant prepared by these methods are poor

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