CS242449B1 - Waste disposal method - Google Patents

Abstract

The purpose of the invention is to dispose of grinding waste, often containing petroleum substances, without polluting the environment and at the same time utilizing the iron contained therein. The stated purpose is achieved by reducing the liquid phase content, adjusting the granulometric composition and processing the waste by agglomeration.

Description

The invention relates to a method of disposing of grinding waste, reducing the liquid phase content, adjusting the granulometric composition and adding the treated waste to a sintering homogenization pile and then treating it through a homogenized sintering mixture.

Grinding steel produces waste with a high iron content and various chromium contents. The content of phosphorus, sulfur, silicon, magnesium and manganese is very low and is therefore not discussed any longer. The content and composition of the liquid phase vary according to the type of waste. The granulometric composition of waste is also very different. Waste after grinding poses a significant threat to the environment.

So far, grinding wastes have been disposed of in several ways. Landfill disposal is the most prevalent and absolutely prevalent. Another way is disposal by incineration. The disadvantage of both methods is the degradation of the environment and the fact that all iron is irreversibly transferred to worthless waste. Their advantage is simplicity. Another method is the briquetting of waste after grinding with subsequent use of briquettes into the steel batch. The disadvantage of this method is the high operating and investment costs, for which the method is applicable only to highly alloyed materials. Occasionally, the method of waste disposal after grinding was used by separately adding the waste to the sinter batch. The disadvantage is the cost of handling, process control and batch inhomogeneity. The advantage of the process is its operability, the recovery of all iron from the waste, and the fact that the process does not require investment costs.

- 2 242 449

The above-mentioned drawbacks are solved by the method according to the invention, which is based on the fact that the waste is treated by reducing the liquid phase content by physical techniques, the granulometric composition is adjusted for longer by storing under atmospheric conditions The mixture is then screened and added to the homogenisation pile for agglomeration in an amount of up to 2% by weight based on the weight of the pile, and the resulting mixture is agglomerated.

Physical techniques include magnetic passports with pressure rollers, filtration equipment, gutter containers, etc. Storage in atmospheric conditions means a technological dump protected by water management where the material is in bulk, accessible to air flow, precipitation and sunshine. The storage time is individual according to the type of waste and atmospheric conditions.

Sorting means separation of coarse pieces over 50 mm, eg by manual collection.

The amount of waste introduced into the homogenisation pile is the quantity that is limited:

1. Chromium content

2. The content of organic substances using agglomeration with electrostatic precipitators (maximum of 0.05% by weight, based on the weight of the pile, of organic substances)

Agglomeration treatment means defined collection, addition of fuel (coke dust, anthracite) in an amount of 4 to 7% by weight based on the weight of the homogenised mixture, addition of correction limestone and return agglomerate. The resulting mixture was stirred for two steps with simultaneous addition of water to a total content of 6-8% by weight. The resulting mixture is deposited on a baking belt and ignited. The resulting product is crushed, de-dusted and fed into blast furnaces.

The method according to the invention has the advantage that the waste is not landfilled, thereby saving landfill space

- 3,242,449 and environmental contamination is eliminated, all the iron is recovered, part of the coolant is returned to the process, the batch homogeneity is guaranteed and the iron produced in this way is less energy intensive than ore. The process according to the invention does not require investment costs, the operating costs are very low.

Example

The plant produces 1,000 tons of grinding waste per year (in weight%): iron, 60, chromium 2, oil emulsions 20, abrasives and impurities 10, the remainder 8. The waste has a granulometric micro-sponge structure. The liquid phase content is reduced by 50% relative to the gutter containers. The oil emulsion is returned to production. Longer the waste is transported to the technological dump, where it is exposed to atmospheric influences for 20 to 40 days. This results in a modification of the granulometric composition / micro-sponge disintegration due to corrosion processes / and also in the adjustment of the liquid phase content. The waste is sorted and processed on the agglomeration of Třinecké železárny. Due to the high chromium content, a minimum amount of waste is formed, i.e. a continuous layer, which is 0.35% by weight based on the weight of the pile.

600 t of iron is obtained with a significant energy saving of 50 t of oil emulsion

000 aP landfill space

The invention can be used in all plants where waste is generated after grinding of previously defined properties.

Claims (1)

SUBJECT OF THE INVENTION 242 449 A method of waste disposal after grinding of defined properties characterized in that the waste is treated by reducing the liquid phase content by physical techniques, further adjusting the granulometric composition by storing it under atmospheric conditions in a layer of eg 2 m for 10 to 100 days according to waste type and atmospheric conditions they are then screened and added to the homogenisation pile for agglomeration in an amount of up to 2% by weight based on the weight of the pile, and the resulting mixture is treated by agglomeration.