Preparation and application of chemical derusting cleaning agent

Abstract

The invention provides a chemical derusting cleaning agent for removing iron rust and other iron compounds on the surface of iron and inside iron components, and a preparation method and application thereof. The chemical derusting cleaning agent consists of the following substances in percentage by weight: 4 to 10 percent of oxalic acid, 0.5 to 1.5 percent of triethanolamine, 3 to 10 percent of phosphoric acid, 0.3 to 1.5 percent of thiourea, 0.2 to 0.6 percent of zinc dihydrogen phosphate or zinc oxide, 0.5 to 2 percent of ethylene diamine tetraacetic acid, 0.5 to 1.2 percent of hexamethylene tetramine, 0.05 to 0.1 percent of sodium dodecyl benzene sulfonate and the balance of water. Chemical derusting cleaning solution prevents over-corrosion and hydrogen embrittlement on a filter matrix through combination effects of a passivator, a corrosion inhibitor, a protective agent and other components in the derusting process, the waste liquor discharge frequency is low, acid mist does not overflow in the cleaning process, and the cleaning agent is environmentally-friendly and harmless to the health of an operator.

Description

technical field [0001] The invention belongs to the field of chemical metallurgy, and more specifically, the invention relates to a novel chemical rust-removing cleaning agent for the surface of iron and steel devices. Background technique [0002] The cleaning and regeneration of the wax oil filter in the F-T synthesis system is a problem that plagues production and scientific research workers. Because the wax produced by the F-T synthesis system is insoluble, with a melting point of up to 120°C and a boiling point of up to 500°C, the iron-containing compound mixed with the wax is firmly bonded to the inside of the filter and cannot be mechanically or chemically Clearing between the multi-layer filter screen and the support layer of the wire mesh filter makes it difficult to clean and regenerate the filter of the F-T reaction system. In actual production, there are often wire mesh filters used to filter wax oil, uncoated metal The phenomenon that the sintered filter is scr...

AI Technical Summary

Problems solved by technology

Mechanical methods such as manual shoveling, grinding, sandblasting, etc., but these methods are only suitable for rust removal on the surface of steel with high impact strength, and cannot remove the rust inside the filter medium of the filter; the use of ultrasonic waves to clean the dirt on the solid surface is also a new method in recent years. However, the filtration channel of the filter is complicated and has a small pore size. It is difficult to turn impurities into fine particles by ultrasonic technology, and it is also difficult to leave the filter through the pores of the filter in a directional manner.

The chemical method using rust remover is currently the most widely used method in industry. At present, there are many kinds of products related to iron and steel rust removers at home and abroad. Rust removers are usually various acids. The problem is that almost all rust removers The formula contains strong acids such as hydrochloric acid and sulfuric acid

Sulfuric acid has poor dissolving ability to iron oxide, and it needs to be carried out at high temperature, which is prone to hydrogen embrittlement and damages the main material of the filter; hydrochloric acid will also cause chloride ion corrosion to the stainless steel material of the filter, and damage the main material of the filter. Over-corrosion, use the existing rust remover formula to remove the filter blockage converted into rust, which is easy to cause damage to the filter body and cause harm to the environment and the health of the operator

[0008] The British Fuel Test Center has tested sintered metal and wire mesh filters for the F-T process slurry bed operation environment, but there is a problem that the filter cannot be regenerated after clogging

DOE in the United States has adopted a cross-flow filter on the F-T synthesis pilot plant in La Porte. In actual operation, there is also the problem that the filter is quickly blocked and cannot be regenerated.

[0009] The inventors also found that after the wire mesh filter in the F-T synthesis unit was clogged and failed, the methods of pickling, alkali washing, and ultrasonic oscillation could not remove the solid wax on the filter, nor could it remove the activity wrapped by solid wax. Iron particles, catalyst supports, iron carbide particles, so filter regeneration is not possible

Wax oil filters in domestic F-T synthesis units and petrochemical units have been scrapped due to filter clogging and failure to regenerate. Regeneration of wax oil filters is a difficult problem in the industry

Images