CS209983B1 - Magnesium source for industrial fertilizers - Google Patents

Abstract

The purpose of the invention is to find a use for magnesite lining of steel furnaces. This was achieved by finding that used magnesite lining from electric and Siemens-Martin furnaces can be used as a source of magnesium for industrial fertilizers, either by direct application or after chemical processing into magnesium fertilizers.

Description

The present invention relates to a novel magnesium source for industrial fertilizers.

A large number of magnesite bricks are used in the construction and repair of Siemens-Martin and electric steel furnaces. This material, worn out by the furnace operation, is replaced at regular intervals with new material. When reconstructing such a furnace, the old magnesium lining is demolished and transported to the boulder, or part of the lining is ground and used as a construction material in the molding shop. Since the magnesite bricks have been exposed to high temperatures of about 1600 ° C for a long period of time, it has been assumed that under these conditions the magnesite bricks burned dead and lost their chemical and agrochemical activity.

It has now been found that the magnesite lining used can be used in agriculture, respectively. in the chemical industry. It is an object of the invention to use spent and mechanically split magnesium lining from electric and Siemene-Martin furnaces as a magnesium source for industrial fertilizers.

The invention is based on the new finding that even in technological conditions during the operation of steel furnaces, a considerable part of the magnesium and calcium of the magnesite lining remains chemically active and, moreover, agrochemically accessible, i.e. it is taken up by plants after incorporation into the soil.

It is known that in many areas of our republic there are acidic soils, which show a lack of magnesium. An advantage of the present invention is that the ground waste raagnesite lining, when applied to the soil, neutralizes its acidity and acts as a magnesium fertilizer, which is absorbed very quickly by plants especially on acid soils. Direct recovery or chemical reprocessing of worthless waste - demolished magnesite linings - reduces the amount of waste material that contributes to environmental sustainability. As experiments have shown, the use of the magnesite lining of the present invention appears to be more advantageous in some cases than the application of kieserite.

It has been found that the magnesite lining used contains 40 to 90 wt. of magnesium oxide, of which 30 to 60 wt. in active form. After grinding to a particle size of less than 1 mm and removal of unsuitable impurities, for example by magnetic separation, they are processed and used according to the invention in various ways such as e.g.

- spread to the field either directly or after mixing with other nutrients, water-soluble magnesium compounds, trace elements, etc.

- decompose with nitric acid and use the solution after separation of the insoluble residue as a liquid fertilizer or as an additive to other types of liquid fertilizers

- directly or after acid decomposition into the process stream of production of multi-component granular fertilizers as a magnesium component

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It is to be understood that the fineness of grinding is governed by the method of further processing and by the type of field spreading device. For example, the fineness of grinding can be characterized by the indication: the sieve residue at 0.315 is 20%.

Examples

Example 1

100 wt. parts of the milled worn magnesite linings from the Siemens-Martin furnace after removal of the iron impurities contained 46.3% by weight. MgO and 17.6 wt. CaO soluble in hydrochloric acid, diluted 1: 1. Fineness of grinding: 48 7 »sieve on sieve 0,2 mm.

The lining thus treated was subsequently leached according to AO No. 161,494 in the presence of 273 wt. % of HNO 3 at a concentration of 34 wt. and 114.3 wt. parts of water. The final pH of the extract was 4.6. After separating the insoluble residue, 415 wt. % of a filtrate containing 31.6 wt. % Mg (H ₂ O) ₂ and 10.2 wt. Ca (H0j) ₂ · This filtrate can be used directly as a liquid fertilizer or mixed with other ingredients, eg nitrogen fertilizer DAM 390 ·

Example 2 A ground magnesite lining of composition and grain size as in Example 1 was tested for agrochemical action on tomatoes and mustard in container speech. The soil used was illimerized, pH / KCl 5.6 with ^a low phosphorus stock and a moderate potassium and magnesium stock. In the bullfinch experiments, the influence of increasing amount of magnesium on the yield of green matter and dry matter of both crops was monitored and the effect of ground lining and kieserite at the same level of basic NPK fertilization in all containers was compared. The results are shown in the following tables. The index in% is a comparison of the milled linings and the kieserite, with the yield of the kieserite fertilized vessels being 100% ·

Table 1

Fertilizing tomatoes. Yield in g / container

Dose MgO g / container Green matter yield Yield of dry matter Kieeerit Lining Index% Kieeerit Lining Index 7 ° 0.5 529 492 95.0 50.8 5 *, 6 107.5 1.0 491 562 11 *, 5 51.7 58.0 112.2 1.5 511 5 * 0 105.8 50.3 58.9 117.1 2,0 * §3 5 * 0 109.5 50.9 60.1 118.1 diameter 506 533 105.7 50.9 57.9 113.7

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Table 2

Mustard fertilization. Yield in g / vessel

Dose MgO g / container Green matter yield Yield of dry matter Kieserit Lining] [ndex% Kieserit Lining Index% o, 5 175 171 97.7 18.3 21.0 114.8 1.0 178 170 95.5 19.6 20.8 106.1 1.5 170 193 113.5 19.4 22.2 114.4 2,0 164 174 106.1 19.6 21.1 107.7 2.5 166 171 103.0 19.2 22.1 115.1 diameter 170.6 175.8 103.0 19.2 21.4 111.6

object of the invention

Claims (1)

Use of spent and mechanically separated magnesite linings from electric and Siemens-Martin furnaces as magnesium sources for industrial fertilizers.