CN-118851369-B - Coal gasification coarse slag-based polyaluminium ferric chloride flocculant and preparation method and application thereof

Abstract

The invention provides a preparation method and application of a polymeric aluminum ferric chloride flocculant based on coal gasification coarse slag. The invention adopts a two-stage acid leaching method (hydrochloric acid-sulfuric acid) to leach metal ions such as Al 3+ , fe 3+ and the like in coal gasification coarse slag, and mixes the two leaching solutions in proportion to carry out a large-scale flocculation test, wherein the optimal process conditions are that the hydrochloric acid, the acid and the hydrochloric acid have the concentration of 8mol/L, the liquid-solid ratio is 30:1, the acid leaching temperature is 80 ℃, the acid leaching time is 1.5h, the sulfuric acid and the sulfuric acid have the concentration of 4mol/L, the liquid-solid ratio is 40:1, the acid leaching temperature is 60 ℃, the acid leaching time is 2.0h, the hydrochloric acid leaching solution and the sulfuric acid leaching solution are mixed according to the volume ratio of 1:1, and the polymerization reaction is carried out under the condition of pH value of 1, and finally the coal gasification coarse slag-based polyaluminum ferric chloride flocculant is obtained. The invention not only improves the high value utilization rate of coal gasification coarse slag, but also realizes the effective treatment of coal washing wastewater, and achieves the purpose of treating waste by waste.

Inventors

• LI JIAN
• CHEN BI
• YANG YONGLIN
• SUN LE
• WANG JINLI
• WEN JIALE
• YAN LONG
• YAN QI
• WANG HAIYU
• FAN XIAOYONG
• WANG YUFEI
• ZHANG PENGFENG
• WEI QINGBO

Assignees

• 榆林学院

Dates

Publication Date

20260512

Application Date

20240705

Claims (4)

1. 1. The preparation method of the polyaluminum ferric chloride flocculant based on the coal gasification coarse slag is characterized by comprising the following steps of: (1) Adding HCl solution and gasified coarse slag into a container, placing the container in a constant-temperature water bath, heating and stirring for reaction, standing for layering, taking out supernatant, placing the supernatant in a No.1 reagent bottle for standby, placing the rest reactants in a centrifugal separator for solid-liquid separation, taking out liquid, placing the liquid in a No.1 reagent bottle for standby, washing residues with deionized water for 2 times, placing the washed liquid in the No.1 reagent bottle for mixing to obtain HCl leaching solution, and drying and weighing the residues; (2) Adding H 2 SO 4 solution and gasified coarse slag into a container, placing the container into a constant-temperature water bath, heating and stirring for reaction, standing for layering, taking out supernatant, placing the supernatant into a No. 2 reagent bottle for standby, placing the rest reactant into a centrifugal separator for solid-liquid separation, taking out liquid, placing the liquid into a No. 2 reagent bottle for standby, washing residues with deionized water for 2 times, placing the washed liquid into a No. 2 reagent bottle for mixing into H 2 SO 4 leachate, and drying and weighing residues; (3) Polymerization, namely mixing HCl leaching solution and H 2 SO 4 leaching solution, adjusting the pH value, mixing, ageing, drying, synthesizing flocculant, and grinding into powder for later use; In the step (1), the ratio of the addition volume of the HCl solution to the mass of the gasified coarse slag is mL, g= (28-32) 1, the molar concentration of the HCl solution is 7.5-8.5mol/L, and the heating temperature is 75-85 ℃; In the step (2), the ratio of the added volume of the H 2 SO 4 solution to the added mass of the gasified coarse slag is mL, g= (38-42) is 1, the molar concentration of the H 2 SO 4 solution is 3.5-4.5mol/L, and the heating temperature is 55-65 ℃; In the step (3), the mass ratio of the hydrochloric acid leaching solution to the sulfuric acid leaching solution is (0.8-1.2), the pH value is 0.8-1.2, and the aging time is 22-26h.
2. 2. The method for preparing the gasified coarse slag based polyaluminum ferric chloride flocculant according to claim 1, wherein the leaching efficiency of the hydrochloric acid solution and the sulfuric acid solution on metal ions in gasified coarse slag is calculated as follows: ; wherein: d 0 is the initial mass of coal gasification coarse slag and g; d 1 is the quality g of the gasified coarse slag after acid leaching.
3. 3. A gasified coarse slag-based polyaluminum ferric chloride flocculant obtained by the production process as claimed in any one of claims 1 to 2.
4. 4. Use of the gasified coarse slag-based polyaluminum ferric chloride flocculant according to claim 3 for treating coal washing wastewater.

Description

Coal gasification coarse slag-based polyaluminium ferric chloride flocculant and preparation method and application thereof Technical Field The invention relates to the technical field of flocculating agents, in particular to a coal gasification coarse slag-based polymeric aluminum ferric chloride flocculating agent, and a preparation method and application thereof. Background In recent years, the world faces significant challenges such as environmental pollution, ecological imbalance, and shortage of energy resources. In this context, china regards the sustainable development of environmental protection and resource utilization as a core strategy. The elm in Shaanxi is rich in coal resources, and the coal chemical industry is promoted to rise rapidly. However, due to late start-up, some technologies are still immature, so that a large amount of coal gasification coarse slag cannot be effectively utilized, and is usually treated in a landfill or stacking mode. In the development process of the coal industry, the problems of coal washing wastewater, slime water of coal preparation plants, ground flushing wastewater of coal-fired power plants and the like form serious challenges for the ecological environment. The coal washing wastewater is in a suspension state in water due to the characteristics of high turbidity, tiny particles and carrying negative charges, and meanwhile, the coal washing wastewater is always kept turbid under the influence of factors such as gravity, brownian motion and the like. Particularly, the supernatant of the coal washing wastewater after standing and natural precipitation still contains a large amount of black coal slime solid suspended matters, wherein the black coal slime solid suspended matters comprise various chemical reagents and harmful heavy metal components added in the coal preparation process. If the wastewater is not discharged up to standard, the water source can be seriously polluted, the problems of river channel blockage, coal slime loss and the like can be caused, if the wastewater cannot be reasonably recycled, the water resource shortage in the coal industry can be further aggravated, and the production efficiency and the economic benefit are reduced. Therefore, the method aims at effectively treating the coal washing wastewater and becomes an important research topic for improving the environmental protection level and economic benefit of the coal industry. Aiming at the treatment strategy of coal washing wastewater, a novel treatment technology is integrated in addition to the traditional method. The novel methods mainly integrate various treatment resources and apply innovative means such as microorganism treatment technology, microwave treatment technology and the like to practice. Treatment with flocculants belongs to the chemical method in the traditional methods. Common flocculants can be divided into inorganic flocculants and organic flocculants. Inorganic flocculants mainly include low-molecular or high-molecular iron and aluminum flocculants, and composite flocculants. According to the method, a flocculating agent is added into coal washing wastewater, and fine suspended particles and colloid particles are aggregated into larger particles under the actions of collision, adsorption, adhesion and bridging by utilizing dissociation and hydrolysis products of the flocculating agent, so that wastewater is precipitated and purified. This method can effectively reduce turbidity and chromaticity of wastewater, and treat fine suspended matters and colloidal particles which are generally difficult to remove by a natural precipitation method. The flocculation precipitation treatment process comprises the steps of dosing, mixing, reacting, precipitation separation and the like. The method can be used as an independent wastewater treatment method, can be combined with other wastewater treatment methods, and can be used as pretreatment, intermediate treatment or final treatment for treating coal washing wastewater. In the coal washing process, a large amount of wastewater generated by a coal washing plant needs to be recycled. However, a large amount of flocculant is generally required in this process. Market research has shown that in general, 1 to 3 kg of flocculant is consumed to treat one ton of clean coal. As the throughput increases, the amount of flocculant used increases significantly. This not only results in an increase in the cost of the enterprise, but may also adversely affect the water environment. Therefore, the flocculant with low cost and excellent performance is designed, and has important significance for the wastewater treatment market. The gasification slag is taken from Shaanxi lean chemical groups, is an important byproduct generated in the coal gasification process, and has rich chemical components and potential recycling value. The furnace type used for generating the gasification slag is a Texaco gasification furnace, as shown in FIG. 1. B