CS246057B2 - Method of industrial waste detoxication with heavy metals' toxic salt complexes content - Google Patents

Description

246057

The invention relates to a process for the preparation of toxic compounds containing heavy metal salt complexes. In particular, it is the oceans that are produced by the industrial skin treatment. In the case of the skin-sludge extraction, 80 to 95% of water is present. Because of its otherwise high organic content, the sludge can be advantageously used as a slurry. 'Fertilizers if they do not contain highly toxic heavy metal, very trapped by chromium ions,' kte ', get there; from chemical compounds used in leather processing. ul ·;

Sludge combustion is uneconomical due to the high water content. There are a number of methods by which colloidal organic materials can be thickened by the addition of flocculants to facilitate their filterability, thereby avoiding the problem of economically removing water. '

High-water sludges are usually stored in tanks or tanks, but due to the very stringent regulations of the environment, it is very difficult to select a suitable site for this purpose.

For the time being, the elimination of toxic materials and valuable waste sludge constituents has not been done, without suggesting a way to solve this problem.

The invention relates to the removal of heavy metal salts, in particular chromium salts, from the wastes mentioned, and the remainder containing organic materials and not to environmental regulations can then be used in agriculture. The present invention is based on the discovery that the heavy metal compounds present in the form of various organic or inorganic complexes or their water-insoluble precipitates can be decomposed by inorganic acids and removed from the sludge in a water-soluble form. SUMMARY OF THE INVENTION The present invention provides a method for detoxifying industrial wastes containing toxic heavy metal salt complexes, particularly wastes, for the treatment of skins containing complexes of heavy heavy metal salts and organic materials, characterized in that the slurry is homogenized with water to form a slurry. containing not more than 100 kg / m 3, preferably 20 to 40 kg / m 3 of solids, is added acid-acidic and / or a mixture of inorganic acids containing hydrochloric acid and / or phosphoric acid containing at least 30% by weight sulfuric acid such that the concentration the acid does not exceed 10% by weight, based on the total weight of the slurry, and the pH of the mixture is less than 1 after completion of the acid treatment, the mixture is stirred at room temperature for at least one hour, the acid-reacting liquid containing heavy metal salts is separated from the sludge and after neutralization of the ky of the mixture with sodium hydroxide, carbonate with sodium or calcium hydroxide, the hydroxides and / or heavy metal carbonates are precipitated at pH 8 to 10, the washing is cleaned, and the organic sludge is eluted for up to 10 minutes free of both metal and acid ions. If the acid or the mixture of acids used to decompose the complexes does not contain sulfuric acid, the separation, sedimentation and filtration of the suspension are considerably more difficult; than'. this is in the presence of sulfuric acid. The decomposition rate of the complexes is sufficient at room temperature, so the reaction is. at the initial temperature of the slurry, with higher temperatures, however, the reaction speed increases.

Upon completion of the temperature-dependent reaction, the suspension is concentrated, for example, by washing heavy metal ions with dilute sulfuric acid, neutralizing the residue with slaked lime, and then separating it from the solution. . . ·· ,, βοΐΐ. heavy ,. metal, separated from the sludge, concentrate! by precipitation and then folding like that. the specified location or reuse. The method according to the invention is shown in the block diagram. . , Example i

The chromium ions are removed from the fermented sludge after treatment with the following skin composition: dry solids content, 200 kg / m 3 organic matter content 100 kg / m 3 chromium ion content · · 12 kg / m 3 kai ηιίηίοίο its content ions zinc and cadmium and a greater amount of iron and calcium ions. The calcium and admixture are mixed with the vapor b in volume 1-6 in the Momogenizer 1 or mixed with the acidic water containing chromium ions from the homogenizer. The resulting homogeneous slurry is fed to dorekatore 2, to which 150 kilograms of sulfuric acid is also added at a concentration of 96% per m 3 of slurry, and the reaction is carried out at the sludge temperature with vigorous stirring for 60 minutes. the slurry feeds into the system 4 washing and separation, and then into the system 5 for neutralization and separation, as a result of the obtaining a heavy metal ion-free g, which is neutralized with slaked lime from the system 4, the washing water f is fed to the homogenizer 1. From the separator 3, the chromium-containing solution is fed to a precipitation apparatus 6 in which metal salts are precipitated at pH 8 to 10 which are treated with slaked lime. The heavy metal-containing precipitate is separated from the alkaline-reacting water in the second separator 7.

Claims (2)

EXAMPLE 2 Chromium ions can be removed by the process of the invention from sludge containing 80 kg / m 3 of dry matter, 60 kg / m 3 of organic substances and 4.5 kg / m 3 of chromium ions, and simultaneously the ceilings of zinc, lead and copper ions. also iron and calcium ions. The sludge a is mixed in the homogenizer 1 with water 1 in a volume ratio of 1: 1 or in a ratio with the liquid leaving the washing and separation system 4, and the suspension is then fed to reactor 2 where it is mixed 1: 1 with acid. sulfuric mixture, which contains 40 kg of sulfuric acid, 10 kg of hydrochloric acid and 10 kg of nitric acid / m 3 of the mixture, the mixture is then left in reactor 2 for 2 hours and then the dry suspension is concentrated in separator 3, concentrated the suspension is washed in system 4 for washing and separation with water or dilute sulfuric acid d until chromium-free, and if it is necessary to keep the pH below 2.5, sulfuric acid may be added, then the washed sludge is fed to the neutralization and separation system 5, where slaked lime is added to the sludge. The washing liquid from system 4 is fed to homogenizer 1 and the chromium-containing solution from separator 3 is passed over the precipitator The apparatus of claim 6 wherein the slaked lime, sodium hydroxide, or carbonate precipitate is precipitated in the form of a heavy ic precipitate. The advantages of the process of the present invention are that it provides a solution to the problem of protecting the environment. the waste ducts of the leather processing industry and avoids the need to use storage equipment for the transport of toxic suspension, allows the use of sludges to contain high levels of organic matter for agricultural purposes, such as soil improvers; it is very easy to isolate valuable components from a high-heavy precipitate. '............. AND SUBJECT MATTER 1.. detoxification of industrial complexes containing toxic complexes, solubilizing metals, especially estimates of the leather processing industry, which contain its complexytoxic heavy metal salts and organic materials, characterized in that it is homogenized with water, optionally acidified, while stirring to form a slurry containing at most 100 kg / m 3, preferably 20 to 40 kg / m 3 of pollutants, is added sulfuric acid and / or a mixture of inorganic acids containing hydrochloric acid and / or phosphoric acid of at least 30 wt. % of sulfuric acid such that the acid concentration does not exceed 10% by weight, based on. the total weight of the slurry and the mixture is less than 1 after completion of the acid treatment, the mixture is stirred at room temperature for at least one hour, the acid-reacting liquid containing heavy cones is separated and the acidic mixture is neutralized with sodium hydroxide; Sodium carbonate or hydroxycalcium hydroxide precipitates the hydroxides and / or carbonate-heavy metals at pH 8 to 10, washing the organic sludge for a long time until it is free of metal ions and acid. | and 2. Method according to claim 1, characterized in that the liquid used for washing is returned and used to homogenize the suspension. 1 sheet of drawings