DD240736A1 - PROCESS FOR PRODUCING CALIDUENIC AGENTS - Google Patents

Abstract

The invention relates to a method for producing Kaliduengemitteln from crude salts containing considerable amounts of carnallite. Their realization is intended to ensure effective processing of such raw materials. According to the invention, comminution to the necessary grain size is to be achieved in a first stage with aggregates which operate by means of an impact effect. This achieves a most extensive and selective enrichment of the carnallite in the fines, which can thus be separated by a Klassierprozess. By treating this fine material with flotation-containing carrying solution, the magnesium chloride can be transferred into the liquid phase and can then be refined. The liberated from the solution magnesium chloride solid can be processed without problems. The magnesium chloride compatibility of the processing method is increased many times over. The invention can be used in all systems for processing carnallite-containing potash salts.

Description

The pulp can be thickened and optionally filtered. The necessary dehumidification is determined by the magnesium chloride content of the feed material, the separating quality of the classification stage and the magnesium chloride compatibility of the subsequent flotation process. The solids containing predominantly fine-grained material can be enriched independently in a known manner or can also be added to the previously separated coarse material after it has been comminuted to processing fineness in any desired manner, and then further treated together.

The described endurance of magnesium chlorides now succeeds in successfully carrying out the processing process.

The desired high rates of product quality and yield are achieved. The required specific collector dose can be minimized.

Another advantage of the separation of the magnesium chloride is the avoidance of Kaliverlusten. This can be further supported by suitable composition of the mash solution.

The enrichment of magnesium chloride in a partial stream of processing and the resulting treatment of this subset allows the apparatus and economic minimization of MgCl ₂ separation.

The realization of the proposed method according to the invention allows both the direct use of potassium chloride contained in carnallite and the further refinement of magnesium chloride to high-quality chemicals by further processing of the resulting liquid phase. An environmental impact due to lye repellency is effectively avoided.

The above invention will be explained in more detail with the following embodiment.

embodiment

A sylvinitic crude salt is processed by a Sylvinflotationsverfahren to high quality potash fertilizers. The process includes comminution, enrichment and product upgrading. For reasons of process economics, the magnesium chloride content in crude salt must be limited to 1.5 percent. This value represents the compatibility limit. It is determined by expenses, costs, throughput capacity and product quality, which do not fall below 60 percent K ₂ O content

The deliberate, forced endurance of higher levels of carnallitic raw salt requires additional mining expenditures and means loss of raw material during extraction and processing.

According to the present invention, a first crushing stage is equipped with an impact mill. In addition to achieving a high proportion of finished product in flotation fineness of less than 1 mm grain size, this comminution makes it possible to enrich at least three quarters of the amount of carnallite contained in the crude salt in this granulation range. This good is by an effective classification process, for example, on ram vibrating screens, separated and with Flotationslauge, which was adjusted to a content of flotation agents, in particular fatty amines of 100 mg / l, mashed. In a dewatering process carried out with hydrocyclones and band cell filters, the solid is largely separated from the magnesium chloride. The solid is added to the flotation feed. The flotation process can now be carried out with high effectiveness despite its increased carnallite content, for example to 10 percent within its magnesium chloride compatibility. Achieving the required chemical and physical product quality no longer causes any difficulties.

By the separation of the magnesium chloride in liquid form, the treatment is a suitable brine available, which is processed into sintered MgO. Environmental pollution no longer occurs. A fiber was converted into raw material.

Claims (2)

Invention claim: 1. A process for the production of potash fertilizers from carnallithaltigen crude salts, characterized in that the crude salt is fed in at least one stage of a dry crushing using the impact principle, whereby it is achieved that accumulate the carnallitic components in the fines and separated with this by a Klassiervorgang be milled the fines in a flotation-containing carrying solution and separated after the passage of magnesium chlorides in the solution of this and the rest of the good is recycled or processed separately. 2. The method according to item 1, characterized in that the separated magnesium chloride-containing liquid phase is fed to a further refinement in a conventional manner. Field of application of the invention The invention relates to the processing sylvinhaltiger raw materials with considerable Carnallitanteil to high quality Kalidüngesalzen. Their application can take place both in the plants operated by the flotation process and in other process principles, such as, for example, the hot-dissolving and electro-sorting processes. Characteristic of the known technical solutions In practical cases, the potash-containing valuable substances are associated with other soluble salts and foreign minerals, which have a disruptive effect on the processing process. The flotation process to be considered here in particular impairs in particular the carnallite as a result of the magnesium chloride obtained during processing and the finely dispersed constituents. The carnallite is a diverse negative influence. Although it contains a significant proportion of potash, its occurrence causes a deterioration of the flotation conditions both due to altered aero-hydrodynamic conditions in the pulp and by reduced efficiency of the flotation reagents. The efficiencies resulting from this complex are mainly reflected in a decrease in the physico-chemical product quality, a decrease in processing capacity and yield, and an increase in reagent costs. There is an upper compatibility limit for the permissible carnallite content in the feed material, which is determined by the requirements of the process codes. Significant losses are incurred in the required repulsion of the final liquors, which also burden the environment as a pollutant noticeably. The previous proposals to eliminate the existing difficulties and problems have been unsuccessful, as they only seek to counteract the harmful effects of magnesium chloride without effectively eliminating their causes. Although the method proposed in DD WP 35 376 envisages enrichment in the decomposition solutions, it is therefore not possible to obtain a product with the desired value of 60% K ₂ O. Although the decomposition to be carried out directly in the flotation apparatus according to DD WP 35 801 and DE PS 880 431 does not lead to apparatus advantages to the solution of the problems indicated, since the carrier liquor is strongly enriched in magnesium chloride. Other recommendations relate to the separate (SU PS 578 109) or stepwise flotation (DD WP 147 059) different grain sizes. Again, the improvements remain unsatisfactory due to the small increase in Magnesiumchloridverträglichkeit. Also, it has not yet been possible by reagent-based measures, such as are the subject of the inventions of DE PS 895 287, DD AP 64 275 or US PS 3 009 575 and US PS 3,640,385, to achieve satisfactory results. Thus, despite a large number of proposals, the flotation of carnallitic raw materials has not yet become an industrial practice, although there is an urgent need and the economic benefit is beyond doubt. Object of the invention It is the object of the present invention to improve the process economy in the production of high quality potash fertilizers from carnallitic crude salts. Explanation of the essence of the invention It is the object, in addition to the solution of the known prior art problems of Sylvinflotation carnallitic crude salt to bring about the use of recyclables contained in carnallite. According to the invention, the crude salt extracted from the pit and containing carnallite is fed to a special comminution, which ensures that the carnallitic material is uncovered. It has been found that under certain conditions, the carnallite can be enriched in the fine-grained Good, which means its depletion in coarse salt at the same time. This can be achieved with an impact-based dry comminution mode. Thus, by a Klassierprozeß, which can also serve for the separation of coarse-grained fractions before further crushing stages, the carnallitic salt largely separately recoverable. The choice of cut size determines the degree of carnallite deposition. However, it is also influenced by other process variables. In the upper limit case, the separation grain size corresponds to the maximum grain size of the flotation task. In the following mashing process with carrying solution, for example in a stirred tank, the magnesium chloride passes completely into the liquid phase, while the suspended solid contains all the potassium-carrying valuable substances. The flotation agent contained in the carrier liquor surprisingly show a positive, process-enhancing effect. The dissolved magnesium chloride can thus be removed according to the invention from the Sylvingewinnungsprozeß.