Method for removing chromium and nickel in acid washing waste liquor

Abstract

The invention relates to a method for removing chromium and nickel in acid washing waste liquor. The method is implemented as follows: a removal process is specifically divided into the following two steps: adding a proper amount of iron powder into the acid washing waste liquor, performing reaction for a period of time at proper temperature and stirring speed, filtering and separating the acid washing waste liquor and the iron powder, adding a proper amount of nano-iron into the acid washing waste liquor, performing reaction for a period of time at proper temperature and stirring speed, and filtering and separating the acid washing waste liquor and the nano-iron. The acid washing waste liquor from which heavy metals are removed is consistent with the national standard HG / T4200-2011 about a raw material ferrous chloride for polyferric chloride, and can be used for preparing an iron-based coagulant. The method provided by the invention is simple, fast, low in cost and energy consumption and environment-friendly, and has a good removal effect on chromium and nickel ions with a relatively high concentration, a broad application prospect and high industrial application value.

Description

Technical field [0001] The present invention relates to the recovery and utilization of waste pickling liquid containing nickel, chromium and other heavy metal ions, as well as a technology for removing or recovering chromium, nickel and other heavy metal ions in the waste pickling liquid, in particular to a removal of waste pickling liquid The chromium-nickel method. Background technique [0002] In the production process of steel products, in order to make the metal surface clean, improve the surface structure of the steel and process the surface, the steel products are usually pickled with hydrochloric acid or sulfuric acid or a mixed acid solution of hydrochloric acid and sulfuric acid to remove iron oxide on the surface. Rust. As the pickling process progresses, the concentration of metal ions in the pickling solution increases, the acidity decreases, and the cleaning of the pickling solution significantly reduces the corrosion effect, and finally becomes the corresponding ...

AI Technical Summary

Problems solved by technology

Among the currently published patents, Japanese Patent No. 6-127946 proposes an improved method for recovering copper and nickel in ferric chloride waste liquid, adding iron powder to the strong acid waste liquid containing copper and nickel to control the oxidation of waste liquid The reduction potential and the concentration of iron ions make the copper and nickel in the strong acid waste liquid precipitate out to achieve the purpose of removing copper and nickel; Chinese patent CN105668754A proposes to add iron powder / zinc powder, or a combination of iron powder and zinc powder mixture to remove heavy metal ions in the pickling waste liquid, and achieved a good removal effect, but did not remove chromium ions very well; Chinese patent CN101759250A proposes to use ceramic membrane permeate to achieve the separation of acid and salt through diffusion dialysis. The purpose of reclaiming heavy metal salts, but this method is only suitable for processing low-concentration, small-scale pickling waste; China's patent CN104787928 proposes a three-step method to reclaim iron, chromium and nickel in stainless steel pickling waste: first in Separation of trivalent chromium ions under alkaline conditions, and then precipitation of trivalent chromium ions in the form of hydroxides under acidic conditions, and finally separation of nickel and iron elements by ammonia leaching or fractional precipitation. This method is complicated to operate. Simultaneously, adjusting pH also makes the processing time longer and the cost is higher; China's patent CN103484888A proposes to first reduce the hexavalent chromium containing sulfuric acid pickling waste liquid to trivalent chromium, and then add sodium sulfide to form corresponding sulfides to achieve precipitation of copper, For the purpose of nickel and iron, add sulfuric acid pickling waste liquid to release iron ions, add sulfuric acid and sodium bisulfite to the supernatant after solid-liquid separation to reduce the remaining hexavalent chromium, then add sodium hydroxide to form chromium hydroxide precipitation , this treatment method does not remove nickel very well, and the treatment process is cumbersome, and the sulfuric acid and sodium bisulfite used all increase the cost of the treatment process a lot; Chinese patent CN104805291A proposes to use sodium hydroxide solution to control the pH of the solution to reach iron , chromium, and nickel are precipitated step by step, but this makes iron and heavy metals chromium and nickel mixed, and the purpose of recycling iron cannot be achieved, resulting in a waste of resources