DD210819A3 - METHOD FOR RECEIVING MATERIALS FROM USED LECELOCE ELEMENTS - Google Patents

Abstract

The invention relates to a process for recovering materials from spent Leclanche cells. This process makes it possible to recover the chemical elements zinc and manganese, or their compounds, present in the unusable cells in a form for which there is a technical application. According to previously known patents, spent Leclanche cells are processed in such a way that predominantly one element is recovered, or its compounds are present in a low valency after hydrochloric acid digestion, making them unfavorable for further processing. According to the invention, this problem is solved by separating unwanted chlorides as completely as possible after comminution of the cell with an aqueous leaching process, optionally with the addition of ammonia for further processing. The residue is then digested with sulfuric acid, the solution purified, and electrolyzed to produce zinc and manganese dioxide. Fig. 1

Description

Process for the recovery of materials from spent Leclanch elements

Field of application of the invention

The invention relates to a process for the recovery of materials such as zinc and manganese from spent Leclanch & Eleraenten Leelancheelemente are widely used in industry and the household as dry elements, for example for operating flashlights, watches, portable radios, etc .. They are usually after discharge as "used dry elements" discarded ·

Characteristic of the known technical solutions

Various methods are known for recovering materials from spent lecanic elements.

Wake the Indian PS 127 714, the cells are opened and the reaction products are eliminated · The zinc is washed in hot water and melted with addition of carbon at 800 ⁰ C · The process is very laborious; In addition, no manganese is recovered. According to Japanese Patent No. 7560414, the crushed elements are dissolved in hot hydrochloric acid and lower manganese is obtained in the presence of HgOg. According to Japanese Patent No. 74 106 419, the hydrochloric acid solution is adjusted with ammonia to a pH of 5 and precipitated iron (III) hydroxide. Whereas, according to this patent in the preliminary stage, the batteries are comminuted, subjected to wet screening and iron separation, be after

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Japanese PS 75 01 094, the spent dry cells for 8 hours at 750 ⁰ C in the presence of air roasted and dissolved after crushing to a fine powder in 20% hydrochloric acid.

All of these methods have the disadvantage that one either recovers only one valuable substance or does not make use of the possibility of obtaining high-quality products.

Object of the invention

The object of the invention is a simple process for the complex recovery of economically valuable materials such as zinc and manganese from spent leelanche elements,

Explanation of the essence of the invention

The object of the invention is to prepare Leclanche elements consumed by a simple process in such a way that zinc and manganese or zinc and manganese compounds are recovered in the form of valuable recyclables.

According to the invention the object is achieved in that using different crushing processes of the elements and separation of paper, plastic, potting compound, brass and carbon rods and optionally iron-metallic coatings, the crushed parts in aqueous solutions leached first alkaline or neutral and finally with dilute sulfuric acid and the solution of The sulfates can be electrochemically converted to zinc and manganese dioxide or otherwise · The method is particularly cost if the crushed elements are initially on a dump for a long time and exposed to rain or other natural precipitation. The pre-leaching can be neutral or with the addition of slaked lime or lime milk. Especially with heavily used elements, it is recommended that the most

It is also possible to add lime hydrate to the heap only after neutral leaching, to capture the ammonia gas produced and to introduce it into an aqueous solution for alkaline leaching.

For better electrochemical treatment, it is expedient to add reducing agent in the form of zinc or sulfites to the acidic alkaline bath. The acidic lye bath contains exhausted bath solution of the electrolysis.

embodiment

The invention will be explained in more detail in the following exemplary embodiment. In the accompanying drawings, Pig 1 shows a schematic representation of the method

Pig · 2 Technological Process of Process Parts

The shredded, for example, by a Schneidgranulator wastes of Leclancheelementen 1 are advantageously stored first in an orderly landfill and at the same time vorgelaugt by rainwater or irrigation (route A).

The efficiency of this pre-extraction is increased by the addition of alkalis, preferably hydrated lime (eg Ca (OH) ₂ ) or lime milk. This reduces the ammonia consumption in the subsequent alkaline extraction (route B).

The alkaline extraction takes place in an ascending tubular reactor 2 with screw conveyor 3. The tube reactor 2 is constantly charged via a feed shaft 4. By this arrangement, an extraction at elevated temperature without ammonia losses is made possible in the lower part of the reactor 2a. The moist reaction mixture which has been leached neutral according to route A is now subjected to alkaline leaching in the tube reactor after the countercurrent extrusion. For this purpose, water is added in the upper reactor part 2b

for neutral washing or for dissolving the gaseous ammonia fed in the upper third 2c of the reactor. At the upper end of the chute 4 there is provided with a filter 5 overflow 6, the alkaline extract can be removed. The neutral-washed and chloride-poor to chloride-free extraction material obtained at the discharge 2d of the reactor is washed by means of a suction cell filter 7 and predried.

The alkaline pretreated reaction mixture obtained according to route B is subjected to alkaline extraction with the addition of a portion of the resulting alkaline precleaning solution 8 or additional ammonia solution 9 in a similar tubular reactor, but in a direct current variant. For this purpose, located in the upper third of the tube reactor 2c provided with a filter 5 overflow 6, where the alkaline extract is removed. For neutral washing, water is also fed in at the upper reactor end 2b. The extraction material obtained at discharge 2d is further treated as under route A. The neutral or alkaline extracts or solutions of Nachwäschen be alkalized according to the technological scheme of the process (see Fig. 1), if necessary, and released in a vacuum ammonia ("degassing" stage) · The neutral chloride-free extraction material is the second leaching (acid) supplied , As can be seen from FIG. 2, the first leaching can also be carried out without pre-extraction on stockpile either by the countercurrent or direct current method, then with the addition of alkalis and water. It is also possible to work up the alkaline pre-leached reaction mixture by Route A (countercurrent extraction).

Claims (7)

invention claims A process for the recovery of materials such as zinc and manganese from spent Leclanch elements with steps for comminution of the elements and separation of paper, carbon rods, plastics, potting compound, brass and optionally iron-metal sheathings, characterized in that the comminuted parts in aqueous solutions initially neutral to leached alkaline and then with a sulfuric acid-containing aqueous solution and, if appropriate, the resulting sulfate solution is fed to an electrochemical production of zinc and manganese dioxide · 2. The method according to item 1, characterized ^ ^ that the exhausted bath solution of the electrolysis is used for acid leaching. 3. The method according to item 1, characterized in that the crushed parts are initially for a long time on heap ^ leached by natural rainfall and the resulting solution is collected and processed separately » 4. The method according to item 1, characterized in that the comminuted parts are mixed for alkaline leaching with lime or mixed with lime milk, lie on waste heap, are exposed to precipitation and the resulting solution is collected and processed separately · 5 * Process according to item 1, characterized in that reducing agents such as zinc or sulphites are added to the acidic alkaline bath. « 6 * Process according to items 1 and 3 », characterized in that lime hydrate is added to the separately collected solution, the precipitate formed is separated off and the resulting ammonia gas is introduced into water © 7th method according to item 1, characterized in that the acidic solution before the electrolysis so much precipitate or ammonia water or both according to point 6 is added that the solution has a pH of 4 to 5
and iron is thereby precipitated as hydroxide · For this 2 sheets of drawings