The possibility of using a soda-sulfate mixture - an alkaline waste from the production of caprolactam, as a mineralizing additive in a Portland cement raw mixture containing, as a silica-containing component, flotation tailings of the lead-concentrating plant of Almalyk MMC, has been studied. The effect of this additive on the processes of mineral formation during the synthesis of Portland cement clinker is shown. The possibility of additional recovery of residual non-ferrous metals - lead and copper - by sublimation and trapping of their chlorides has been established.
European "Technical Recommendations" have proposed, in addition to the use of substance concentrations, the use of a pH (≤ 2 or ≥ 11.5) and an acid / base buffering capacity to classify waste into according to their hazardous properties HP 4 'Irritant' and HP 8 'Corrosive'. Buffer capacity refers to a 2018 UK classification guide referring to the 'corrosive' level of a method proposed in 1988 for substances and preparations but not retained in EU regulations. The different methods of classifying products and wastes in terms of corrosivity or irritation are compared. The waste method using pH and buffering capacity is expressed as an acid / base concentration and compared to the product method (CLP). The “corrosive” level of 1988 corresponds to an average acid / base concentration ≥ 14.4Ͽie 14 times less severe than CLP (acid / base concentration ≥ 1Ͽ These methods were applied to five alkaline wastes (pH ≥ 11.5). Minimum pH waste is not classified by both methods, and three higher pH wastes are classified by both methods. Intermediate waste is classified by CLP but not by the proposed waste method. In order not to innovate and create a new divergence between products and waste, it seems preferable to use the product regulations for HP 4 and HP 8. Fortunately, the elimination of the danger HP 4 and HP 8 from acidic or alkaline waste can be obtained by neutralization (possibly by other wastes), including for alkaline wastes by (natural) carbonation by atmospheric CO2.
The main sources of highly concentrated multicomponent technological solutions at thermal power plants (TPPs) are water treatment plants. Analysis of operation of the ion-exchange water treatment plant at the Nizhnekamsk Thermal Power Plant-1 showed that half of alkali supplied to regeneration of the anion-exchange alkali filters is not used, but is discharged for neutralization and then to wastewater. Due to the fact that the cost of alkali used in technological processes is quite high, it is economically feasible to process the alkaline waste with the alkali extraction and its reuse in the production cycle. The article presents the experimental results on the electro-membrane separation of alkaline waste regeneration solutions and wash water after anion-exchange filter regeneration. The revealed differences in the selectivity of various ion transfer through the electrodialysis apparatus membranes, depending on time and amount of transmitted electricity, allowed us to establish the possibility of obtaining an alkaline solution purified from impurities.
Features of The Processes of Clinker Formation When Using Solid Waste From Caprolactic Production As A Mineralizer