4results about How to "Reduce leaching concentration" patented technology

This invention discloses an industrial production method for cement clinker that co-processes heavy metal-containing waste, comprising: raw meal preparation: raw meal is prepared according to the following proportions by weight: 84-87 wt% calcareous raw materials, 6.0-7.2 wt% clayey raw materials, 4.8-5.8 wt% corrective raw materials, and 2.0-4.5 wt% heavy metal-containing waste; addition of composite synergist: a heavy metal adsorption-mineralization composite synergist is added to the raw meal; pre-decomposition: the homogenized raw meal is preheated by a multi-stage cyclone preheater and then enters a decomposition furnace for carbonate decomposition; clinker calcination: the decomposed raw meal enters a rotary kiln and is calcined at 1350-1450℃ to form clinker; and rapid cooling of clinker: the calcined clinker is rapidly cooled to room temperature by a grate cooler to obtain finished cement clinker. This invention can achieve a total solidification rate of heavy metals in clinker of 93%, and increase the retention of Pb, Cd and Zn by 13.9 times, 59.1% and 11.5% respectively, and increase the 28-day compressive strength to 61.8 MPa.

The application discloses a solid waste-based cementing material and a preparation method and application thereof, and belongs to the technical field of building materials. After grading pretreatment of industrial by-product gypsums of different sources, the industrial by-product gypsums are dry-mixed with active mineral admixtures, heavy metal stabilization components and sulfate activators, water is added for first-stage hydration and standing, the sulfate activation is preferentially caused to form ettringite and dihydrate gypsum crystal framework, and then silicate activators are added for second-stage hydration to generate C-(A)-S-H gel, so that the ordered generation of hydration products is realized. Through step-by-step cooperative activation, the early compressive strength is increased by 30%-50% compared with one-time addition of activators, the 28d softening coefficient can reach more than 0.76, meanwhile, the heavy metal ion leaching concentration is reduced by more than 80%, the quality standard requirement of underground water is met, and through the design of special pretreatment processes for desulfurization gypsum, phosphogypsum, fluorogypsum and citric acid gypsum respectively, the same set of modifier composition can adapt to various gypsum sources, and the quality stability is greatly improved.

This invention discloses a method for immobilizing multiple heavy metals in heavy metal-containing residual salts using a microcrystalline reinforced glass body, belonging to the field of hazardous waste harmless and resource-based treatment technology. This method targets residual salts containing heavy metals such as Cr, Pb, and Zn. The residual salts are mixed with silica, limestone, soda ash, and fluorite in a specific ratio, and then melted and homogenized to form a base glass with high sulfur and chlorine tolerance. Based on this, a microcrystalline reinforced glass solidified body with coexisting glass and crystalline phases is constructed through controlled crystallization treatment. This method achieves simultaneous and efficient immobilization of multiple heavy metals such as Cr, Pb, and Zn. The leaching concentrations of Cr, Pb, and Zn in the solidified product are below 0.168 mg / L, 0.207 mg / L, and 0.188 mg / L, respectively, significantly lower than the limits specified in GB / T 41015-2021, demonstrating excellent long-term environmental stability.

The invention provides a preparation method of sludge-based biochar for directionally enriching iron phosphate through synergistic modification of ferrous sulfate and sodium persulfate, and belongs to the technical field of harmless treatment and resource utilization of municipal sludge and environmental functional materials. According to the method disclosed by the invention, active phosphorus in the sludge is converted into a stable iron phosphorus compound in advance through oxidation-complexation dual effects of the ferrous sulfate heptahydrate and the sodium persulfate; the phosphorus-rich sludge is converted into more stable phosphorus-rich biochar through two-step heat treatment, the whole process of sludge pyrolysis is cooperatively regulated and controlled through Fe < 2 + > / S2O8 < 2->, integration of phosphorus release, phosphorus fixation and heavy metal passivation is achieved, the problem that in the prior art, the phosphorus retention rate is low is solved, phosphorus resources in the phosphorus-rich sludge are extremely retained and stabilized, and the phosphorus-rich sludge is obtained. The fixed rate of phosphorus in the modified sludge-based biochar with directionally enriched iron phosphate prepared by the method is greater than 99%.