DE1257657B - Process for processing clayey raw materials - Google Patents

Description

^ FEDERAL REPUBLIC OF GERMANY lnt.CL:

C04b

GERMAN

PATENT OFFICE German class: 80 b - 12/01

EDITORIAL

Number:
File number:
Registration date:
Display day:

1257 657
J 20920 VI b / 80 b
November 29, 1961
December 28, 1967

It is sometimes necessary to use clayey raw materials, such as clay, slate and kaolin, in the form of suspensions to pump through pipelines. Since the clayey raw materials are known to be very fine Colloidal particles usually also have larger particles of a few tenths or a few hundredths Millimeter in diameter as well as impurities consisting of coarse grains of sand, gravel and stone contain, the transport of such suspensions encounters difficulties, since the coarse particles settle easily, causing the lines to clog, and also as a result of the erosive effect of the larger particles cause increased erosion of equipment such as the pump rotors.

It is known to add small amounts of alkaline compounds to the clay-containing suspension in order to reduce their Increase binding strength and flowability, while adding a small amount of acid increases coagulation and causes the sediment to fall.

The addition of electrolytes to the clay-containing suspension, preferably to thin-bodied suspensions, the concentration of which .an clayey substance is low, is known in the slurry process. To accelerate the flow of the suspension, an alkaline substance such as Na ₈ CO ₃ , more rarely NaOH, is often added, which facilitates sedimentation and the separation of coarser particles, such as sand, from the colloidal clay particles. After sedimentation, the suspension of clay particles is decanted, after which an acidic electrolyte, such as H ₂ SO ₄ , alum or aluminum sulfate, is added as a flocculant to separate it from the liquid, coagulating finer into coarse particles and their settling. A slurried product is obtained from the thus compacted and filtered sludge.

It is also known to add an electrolyte to the clay intended for molding, in particular diluting electrolytes such as Na ₈ CO ₈ or NaOH, which are added to the clay suspension previously mentioned with water. The addition of acidic coagulating electrolytes to such clay suspensions, on the other hand, is generally not customary, because this would make the entire mass rigid and consequently lose the physical properties that are valuable for the ceramic; the use of acidic electrolytes takes place only if such clay masses are subjected to a certain mechanical or physicochemical processing, such as. B. after slurrying or when pressing shaped blocks for hardening.

It is essential that the previously known electrolyte additive is always added to the prepared purely aqueous sus-

Process for processing clayey raw materials

Applicant:

Instytut Chemii Ogolnej, Warsaw

Representative:

Dipl.-Chem. L. Zellentin, patent attorney,

Ludwigshafen / Rhine, Halbergstr. 25th

Named as inventor:

Stanislaw Bretsznajder, Warsaw

Claimed priority:

Poland of July 14, 196] (96 949)

pension should take place. Generally, as with slurry, either the alkaline one went first diluting electrolyte, which makes the colloidal suspension binding, and after slurrying the acidic electrolyte is added, the electrolytes being chosen so that they neutralize each other. Or, as in the preparation of the clay used for molding, it became an alkaline one diluting electrolyte or, as stated above, an acidic electrolyte added.

The invention aims to obtain a homogeneous compacted mixture, its particles show no tendency towards rapid sedimentation. Obtaining a homogeneous, binding suspension by adding acidic electrolytes after prior preparation of a purely aqueous clay suspension however did not succeed '; namely, lumps and so-called "noodles" formed in the solution Pumping the liquid and storing it for a long time made impossible.

It has been found that these disadvantages can be overcome by using the suspension water before the clay is mixed in, certain acidic electrolytes are added in sufficiently high concentrations and then stir the clayey raw material into the solution prepared in this way until it consists of clay particles existing lumps have disappeared. In such a method surprisingly the not too large amounts of the fine clay substance during the transition of clay lumps in suspension immediately after coagulation and form fine, homogeneous in terms of their size, coagulated particles. The result is a

709 710/553

Claims (1)

3 4 very liquid and homogeneous, but at the same time as much as 0.2 percent by weight of sulfuric acid and 0.35 percent by weight Liquid that the percent of aluminum ammonium alum suspended in it (sus- coarser particles have no tendency to. quick break B). show cases. This was not to be foreseen; rather after a very careful stirring if there was unwanted flocculation and sedimentation, 5 each suspension survived for 6 hours of sedimentation. but not to expect homogenization. let what you can sample from their proximity to the ground From the suspension obtained can be removed during and the granulometric consistency of the suspension determined the suspension for a somewhat longer period of time than before. impurities in the form of coarser particles, such as sand, were converted to dry matter using granular Separate gravel and rocks. io lometric analysis grains of the following diameter The new process for preparing clay rough knives found: substances by suspending them in electrolyte solution ^ is _{ln in the suspension A 41} o, _{Q over λ} ^ _n According to the invention, characterized in that the 22 8 ° / from Ibis 01mm Raw materials directly in an aqueous solution, the min- 73I ⁰ / below 0 1 now at least 0 ^ 5 percent by weight H ₂ SO ₄ and at least i _{S ln the SuS} p _eQS ion B 1.3 »/ 0 over 1 mm ' 0.2 percent by weight Al ₂ (SO ₄ ) ₃ or at least 0.3 Ge ^r _{16 Q0} / _from ^ _{to 0} ι _mm contains weight percent aluminum ammonium alum, ei Oo / „„ t., niJm
L. · ι ι. -Ii. jj · u c it -ι οΐ, ο 7q under u, l mm.
mechanically distributed and the coarse particles that may remain, such as sand, gravel and stones, from the comparison of the test results that is sieved off and sedimented. ao the homogenizing influence of the essential thing for suspending is that the sulfuric acid-alum solution used to achieve the desired tone clear effect, the selective coagulation occurs quickly; visible - namely, it is noteworthy in the case of the invention that according to the invention, the sedimentation of the coarse clay grains of a relatively dilute solution of sulfuric acid takes place significantly more slowly than is achieved with the clay suspension with acidic and aluminum salt. In contrast to pure water. even remain suspensions in pure water fairly large particles of the clayey raw materials in the sieving of gravel and rock from the clay before solution suspended and show after a long period of time taken, since the sound used is almost nonexistent no tendency to sediment quickly; these are particles larger than 2 mm in diameter has the consequence that the homogenized suspension contained 30. conveyed through pipelines without the risk of clogging can be. Process for processing clayey raw materials Comparative _{experiment ■ by suspending in} electrolyte solutions, since From 200 kg of clay with a granulometric composition, characterized in that the rough settlement (Grain diameter) substances directly in an aqueous solution that min- over 1 mm at least 0.15 percent by weight H ₂ SO ₄ and at least '.'. '.'. '.'. '.'. '.'. '.'. from 1 to 0 * 1 mm, «* ^ns 0.2 percent by weight A1 ₂ (SO ₄ ) ₃ or min- 28.8 »/ ο from 0.1 to 0.01 mm, ^d ? ^sten , ^s ° ' ³ percent by weight of aluminum ammonium ine 0 /., _._ η «-ι ujc η ηης mm 4 ° containing niumalum, mechanically distributed and the 3 ₇ 70 / under 0 005 mm possibly remaining coarse parts, '' 'such as sand, gravel and stones, sieved or removed a suspension was made in 1000 l of water. be mentored.
(Suspension A). In the same way, a second suspension was produced. by suspending the clay in a solution of German Patent No. 343 044, 689 949. 709 710/553 12.67 O Bundesdruckerei Berlin