CS218641B1 - Method of preparation of the stabilized agent of suspensions - Google Patents

Abstract

A method of preparing a suspending agent stabilizing agent based on an aqueous bentonite suspension in sodium form by reacting bentonite pre-dispersed in water at 60 to 95 ° C, is reacted with Na 2 CO 3 in an amount of 3 to 10 wt. % related to bentonite dry in the presence of lignosulfonic acid acid and / or derivatives thereof in an amount of 0.5 to 5.0 wt. % dry matter.

Description

The invention relates to a process for the preparation of stabilizing agents by suspensions based on an aqueous suspension of bentonite in sodium form.

Suspensions are essentially two-phase systems in which the co-continuous phase is a liquid and the discontinuous solid phase is in the form of micro and macroscopic or coarse-dispersed particles. The discontinuity phase usually constitutes a heterodisperse system of solid particles. Suspensions are subject to sedimentation (particles of 1 to 1000 μιη size) whose velocity is, among other factors, within the meaning of Stockes' law for particles of approximately spherical shape, dependent on the square of the radius of the particles. Agglomeration ¹ (formation of larger secondary particles) can occur as a result of the strong electrolytes causing the sedimentation rate to increase. This phenomenon can be partially prevented by using a suitable type of protective colloid. However, in more concentrated suspensions their stabilization with protective colloid alone is not sufficiently effective. Various stabilizing agents, such as hydrophilic aluminum-ferric aluminum silicate clay minerals of the type montmorillonite, attapulgite, sepiolite and others are used to stabilize them. They are clay minerals from the class of glaserites, which were formed by gradual transformation of volcanic rocks, basalt, tuff, tuffite and similar, under specific geological weathering conditions. These minerals currently find practical application eg. in the preparation of suspension fertilizers, where this creates the conditions for the possibility of producing liquid fertilizers with a substantially higher content of nutrients, which is. particularly pronounced for liquid fertilizers containing potassium.

Although some of the above minerals such as attapulgite, exhibit relatively good stabilizing effects even without special treatment in the natural powder state, most suspension manufacturers use stabilizing agents made by further special treatment of these minerals. It is known e.g. TVA procedure "Fluid clay" type 9,2-0-0, come to the preparation of the stabilizing agent is 19.3% of CO _{(NH2) 2} in the form of a 75% solution of urea, and 25% attapulgite. To improve theological properties, 0.55% Na ₄ P ₂ O _{7 is added} as a 20% solution. The components are dispersed in water by stirring for 10 minutes at 1800 rpm ("New Development in Fertilizer Technology" - 12th Demonstration TVA Oct., 1978). Furthermore, a stabilizer called Attaflow is used to stabilize N, NP and NPK suspension fertilizers, concentrated sludge containing sulfur, calcium suspensions, liquid feed mixtures, seeds of some types of agricultural crops, and pesticide formulations. It is a 26-28% dispersion in water attapulgite ^ prepared for mixing of several minutes at 1600 rpm ^first The liquid stabilizer obtained having a pH of 8.5 with a pH = 8.5 has a viscosity determined by Brockfield viscometer of about 400 mPas.

Due to the fact that attapulgite deposits are found only in some countries and are relatively limited, the possibility of preparing stabilizing agents based on other minerals, especially bentonites, is sought. From the hillfort of the most general properties we can distinguish bentonites that swell in water and bentonites that do not swell in water. they swell very little and sediment quickly. The first group includes the so-called. sodium bentonites such as e.g. Wyoming bentonite, which is relatively few. The second group, which is much more widespread, includes mainly calcium bentonites, which are also present in relatively large numbers in Czechoslovakia. Of these calcium bentonites, the swellable bentonites can be obtained by ion exchange reaction with Na ₂ CO _3, so-called. natrification, which may be dry or wet. Wetting is more effective. A disadvantage of such bentonite-treated water-swollen bentonites is the fact that after natrification they acquire a consistency of gel-like pastes which are difficult to handle. As the viscosity value and thus the gelatinity decreases by decreasing the clay concentration in water, the stabilizing effect of the agent also decreases. When bentonite is simply natrified in water, it also has a significant effect on the properties of the stabilizing agent. natrification time, as evidenced by the different properties of the natrified bentonite suspensions immediately after homogenization with Na ₂ CO ₃ resp. after 2,4 or 24 hours.

It has now been found that stabilization with the aqueous suspension of bentonite sodium suspension prepared according to the invention has largely eliminated these disadvantages. The principle of the invention consists in reacting bentonite pre-dispersed in water at 60-95 ° C with Na ₂ CO ₃ and an amount of 3? 10 wt. bentonite dry parts in the presence of lignosulfonic acid and / or its fluidity enhancing derivatives, inhibiting nucleation, coagulation and crystal growth in an amount of 0.5-5.0% dry matter.

It is preferred that lignosulfonic acid derivatives of technical purity which are devoid of sugars by the alcoholic fermentation of Torula utilis yeast, partially desulfonated and oxidized by oxygen or other oxidizing agents, optionally obtained by the action of Ca (OH) ₂ at 30 to 50 ° C. It has been experimentally confirmed that the derivatives already specified are effective in the form of lignosulfonic acid as well as in the form of its calcium, sodium, potassium or ammonium salt.

An advantage of said process for the production of a stabilizing agent is that the resulting product is obtained in the form of a pumpable, easy-to-handle gelling dispersion which, despite the lower apparent viscosity, exhibits a high stabilizing effect. In the process for the production of the stabilizing agent, a continuous process can be used, which is advantageous for its application in large-scale production processes. The stabilizing agent also exhibits high stability in the environment of coagulating inorganic salts.

The following examples illustrate but do not limit the invention.

Example 1

239.9 g of water at 80 ° C were introduced into a mixing vessel with a saw stirrer and 6.4 g of sulphite liquor containing 47% dry matter and 51.5 g of bentonite from the Jelšový potok locality containing 87.4% were added under stirring. solids. After homogenization, 2.2 g of slurry was added slowly and with stirring. Na ₂ CO ₃ . After the addition, the reaction mixture was allowed to stir for an additional 60 minutes. After stirring, the prepared stabilizing agent was used to stabilize the suspension pesticidal preparation Zeazine S-40.

Claims (1)

4 manufacturing processes. The stabilizing agent exhibits high stability even in the environment of coagulating organic salts. The following examples further illustrate the invention. EXAMPLE 1 239.9 g of water at 80 DEG C. were introduced into a stirring vessel with a stirrer, and 6.4 g of a sulphite liquor containing 47% of dry matter and 51.5 g of bentonite from the site of Jelšový potok with a content of 87.4 were added. % dry matter. After homogenization, 2.2 g of sludge were added to the mixture thus obtained while stirring. Na2CO3. The reaction mixture was allowed to stir for a further 60 minutes. After stirring, the ready stabilizing agent was used to stabilize the Zeazine S-40 suspension pesticide formulation. SUBJECT A method of preparing a stabilizing agent suspension of an aqueous suspension of bentonite in a sodium form, wherein the bentonite is reacted in water at 60 to 95 ° C. Example 2 324.8 kg of H2O were fed to 5001 boilers with anchor stirrer and duplicator, 23.8 kg of sulphite liquor containing 45% dry matter and 77.2 kg of bentonite containing 87.4% dry matter. During the homogenization, the mixture was heated to 95 ° C and dosed at 9.5 kg.min-1 into the mixer. by siphon overflow, into which a 14% Na 2 CO 3 solution is metered in at a rate of 0.5 kg / min -1. The resulting reaction mixture was drained into another anchor stirrer where the reaction continued for 45 minutes of stirring. The prepared stabilizing agents characterized by a viscosity of 350 mPas (to divide the non-pumped gel prepared without lignin additive) were used to produce a stable base suspension of 10-10-30 (N-P2O5-K2O). OF THE INVENTION with Na 2 CO 3 in an amount of 3 to 10 wt. % relative to the bentonite solids in the presence of lignosulfonic acid and / or derivatives thereof in an amount of 0.5 to 5.0 wt. % dry matter. Printed by Moravské tiskařské závody, provoz 12, Leninova 21, Olomouc Price: 2,40 Kčs