Abstract

An ultra-stable mineralized soil remediation material for farmland contaminated by heavy metals. The material comprises, in parts by mass, 16-18 parts of limestone, 12-15 parts of gypsum ores, 12-15 parts of bauxite, 4-5 parts of medical stone and 8-10 parts of biochar. Further disclosed is a method for using the remediation material, the method comprising the following steps: 1) taking a soil sample from farmland to be remediated, and measuring the contamination degree of the soil sample; 2) digging furrows; 3) uniformly spreading the material on the furrows by means of a soil conditioner spreading and spraying all-in-one machine; 4) burying and trowelling the furrows, and irrigating same to ensure that the water content of soil is 20-25%; and (5) after 10-15 days, achieving the remediation of soil contaminated by heavy metals. By means of the method, the heavy metal content of soil can keep in line with the soil environment quality standards in China for 5 years or longer, the maintenance cost is reduced, and the maintenance effect is improved.

IPC Classes  ?

• B09C 1/08 - Reclamation of contaminated soil chemically

Abstract

2233 content is not less than 15%. The arsenic-contaminated soil remediation material is spread into contaminated soil, the pH values of both acid soil and alkaline soil can be automatically regulated, the arsenic activity in the soil environment is reduced, the activity of arsenic-resistant bacteria is improved, and the soil environment is stabilized by means of the calcium-aluminum hydrotalcite. The arsenic-contaminated soil remediation material has remarkable effects on repairing and improving soil, reducing environmental pollution, enhancing food safety, and increasing crop yield.

IPC Classes  ?

• C09K 17/40 - Soil-conditioning materials or soil-stabilising materials containing mixtures of inorganic and organic compounds
• C09K 17/08 - Aluminium compounds, e.g. aluminium hydroxide
• C09K 101/00 - Agricultural use
• C09K 109/00 - MATERIALS FOR APPLICATIONS NOT OTHERWISE PROVIDED FORAPPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR pH regulation

Abstract

Provided is a high-purity, high-yield, low-energy consumption and pollution-free method for separating and purifying p-dichlorobenzene, which mainly includes solventing-out precipitation and fractional crystallization steps, wherein the solventing-out precipitation is as follows: putting a p-dichlorobenzene mixture in an ethanol solution, then adding distilled water and controlling the temperature at 5°C-8°C, and standing to obtain p-dichlorobenzene with a purity of 80%-88%; and then fractionally crystallizing (i.e. two-stage and six-section melt crystallizing and refining) the p-dichlorobenzene with the above-mentioned concentration to obtain the p-dichlorobenzene product with a purity of more than 99.9% and a yield of more than 90%. The composite separation and purification method uses ethanol as a main solvent and water as a precipitation agent, and is low in solvent costs, free from pollution, mild in process conditions, and convenient in operation; and in each step of the fractional crystallization process, a DCS system is used to realize the continuous production, reduce the sublimation and loss of the raw material, and then improve the handling capacity and product quality.

IPC Classes  ?

• C07C 17/392 - SeparationPurificationStabilisationUse of additives by crystallisationPurification or separation of the crystals
• C07C 25/08 - Dichloro-benzenes

Abstract

Disclosed is a process for fractional crystallization of p-dichlorobenzene. 80 wt% of p-dichlorobenzene is used as raw materials. In a fractional crystallizer, the raw materials are refined by using a secondary six-section melt crystallization technology to obtain a product with a mass percentage of the p-dichlorobenzene being more than 99.8%. In the present invention, the process has a simple operation, has a high product yield and low energy consumption, and is easy to be popularized and applied.

IPC Classes  ?

• C07C 17/392 - SeparationPurificationStabilisationUse of additives by crystallisationPurification or separation of the crystals
• C07C 25/08 - Dichloro-benzenes